:A*f , ,7* > *r QE C64- L8 lv9IO J r nC -. . V.W U 'V* --V '.Ml '. -jju » ^4^ * tyamtll Imwraitg ffithratg Sttfaca, SJem $otlt BOUGHT WITH THE INCOME OF THE SAGE ENDOWMENT FUND THE GIFT OF HENRY W. SAGE 1691 The date shows when this volume was taken. To renew this book copy the call No. and give to the librarian. HOME USE RULES All Books subject to Recall All borrowers must regis- ter in the library to borrow books for home use. All books must be re- turned at end of college year for inspection and repairs. Limited books must be re- turned within the four week limit and not renewed. Students must return, all books before leaving town. Officers should arrange for the return of books wanted during their absence from town. Volumes of periodicals and of pamphlets are held in the library as much as possible. For special pur- poses they are given out for a limited time. Borrowers should not use their library privileges for the benefit of other persons. Books of special value and gift books, when the giver wishes it, are not allowed to circulate. Readers are asked to re- port all cases of books marked or mutilated. Do not deface books by marks and writing. Cornell University Library QE 264.C64L8 1910 The geology of East Lothian including pa 3 1924 004 026 443 Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924004026443 33 MEMOIRS OF THE GEOLOGICAL SURVEY. SCOTLAND. THE GEOLOGY OF EAST LOTHIAN, INCLUDING PARTS OP THE COUNTIES OF EDINBURGH AND BERWICK. (EXPLANATION OF SHEET 33, WITH PARTS OF 34 & 41.) Second Edition- revised AND RE-WRITTEN BY C. T. CLOUGH, M.A.; G. BARROW; C. B. CRAMPTON, M.B., CM.; H. B. MAUFE, B.A. ; E. B. BAILEY, B.A. ; and E. M. ANDERSON, M.A., B.Sc. WITH CONTRIBUTIONS ON THE SILURIAN TABLELAND by B. N. PEACH, LL.D., F.R.S. and JOHN HORXE, LL.D., F.R.S. PUBLISHED BY ORDER Or THE LORDS COMMISSIONERS Off HIS MAJESTY'S TBEASUEY. EDINBURGH : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE By MORRISON & GIBB LIMITED, At Tanpteld. And to be purchased from E. STANFORD, 12, 13, and 14 Long Acre, London; W. & A. K. JOHNSTON, LIMITED, 2 St. Andrew Square, Edinburgh; HODGES, FIGGIS & CO., Grafton Street, Dublin. From any Agent for the sale of Ordnance Survey Maps ; or through any Bookseller, from T. FISHER UNWIN, 1 Adelphi Terrace, London, W.C., who is the sole Wholesale Agent to the Trade outside the County of London. 1910. Price Four Shillings and Sixpence. LIST OF PUBLICATIONS OF THE GEOLOGICAL SURVEY OF SCOTLAND. Geological Map (25 miles to the inch) of the British Islands. Price, Coloured,. 2s. ; Unooloured, Is. Maps on One-inch Scale. (New edition. Colour-printed.) 33. Haddingtonshire and parts of Edinburghshire and Berwickshire, is. 6d. (See reference to First Edition under Hand-coloured Maps.) Maps on One-inch Scale. (Hand coloured.) 1. Wigtownshire, South-Western Districts. 2s. 3d. 2. Wigtownshire, South-Eastern Districts. 2s. 3c?. 3. Wigtownshire, Western Districts. 5s. 9c?. 4. Wigtownshire, East Part ; Kirkcudbrightshire, portion of S.W. Division. 9s: 6c?. 5. Kirkcudbrightshire, Southern Districts. 13s. 3d. 6. Kirkcudbrightshire, E. margin ; Dumfriesshire, S. margin. 3s; Gd. 7. Ayrshire, South- Western Districts. 7s. 3c?. 8. Kirkcudbrightshire, Ayrshire, and Wigtownshire (parts of). 16s. 3d. 9. Kirkcudbrightshire, N.E. ; Dumfriesshire, S.W. lis. 9d. 10. Dumfriesshire. 10s. 3d. 11. Roxburghshire and Dumfriesshire (parts of). 5s. 9c?. 12. Argyllshire (Kintyre, S. half of), lis. 13. Ayrshire, Turnberry Point, and S. part of Arran (Solid and Drift editions). 7s. 3c?. 14. Ayrshire, Central Districts. 14s. 15. Dumfriesshire, N.W. ; Ayrshire, S.E. ; and Lanarkshire, S. lis. 16. Dumfries, Selkirk, Peebles, Lanark, and Roxburgh shires (parts of), lis. 17. Roxburghshire, Selkirkshire, and Dumfriesshire (parts of). 10s. 3c?. 18. Roxburghshire, E. part. 2s. 9c?. 19. Argyllshire (S. part of Islay). 10s. 3c?. 20. Argyllshire (Kintyre, Gigha I., part of Islay). 9s. 6c?. 21. Argyllshire ; Arran, Central and N. part ; Bute, S. part ; Cumbraes, Ayrshire (part of N.W.) (Solid and Drift editions). 16s. 3c?. 22. Ayrshire, Renfrewshire, Lanarkshire (parts of). 14s. 9c?. 23. Lanarkshire, Central Districts ; Ayrshire (part of W.). 19s. 3c?. 24. Peeblesshire, Lanarkshire, Edinburghshire, Selkirkshire (parts of). 8s. 9c?. 25. Berwick, Roxburgh, Selkirk, and Edinburgh shires (parts of). 8s. 9c?. 26. Berwickshire and Roxburghshire (parts of). 3s. 3c?. 27. Argyllshire ; parts of Islay and Jura, Oronsay. 8s. 29. Argyllshire, Ayrshire, Buteshire, Dumbartonshire, and Renfrewshire (parts of). 21s. 6c?. 30. Renfrewshire ; parts of Dumbarton, Stirling, Lanark, and Ayr. 16s. 3c?. 31. Lanarkshire, Stirlingshire, Linlithgowshire, Dumbartonshire, Edinburgh- shire (parts of). 16s. 3c?. 32. Edinburghshire, Linlithgowshire, Fifeshire, Peeblesshire (parts of). 13s. 3c?. 33. Haddingtonshire and parts of Edinburghshire and Berwickshire (first edition). 10s. 3c?. 34. Eastern Berwickshire. 3s. 6c?. 36. Seaboard of Mid Argyll (Solid and Drift editions). 16s. 3c?. 37. Mid Argyll (Solid and Drift editions). 25s. 3d. 38. Perthshire, Stirlingshire, Dumbartonshire, Argyllshire (parts of). 14s. 9c?. 39. Perthshire, Clackmannanshire, Stirlingshire, and Fifeshire (parts of). 17s. 9c?. 40. Fife and Kinross. 14s. 9c?. 41. Fife, East part ; Haddingtonshire, North part. 5s. 9c?. 45. Argyllshire, Country near Oban and Dalmally (Solid and Drift editions). 25s. 3c?. 46. Perthshire, Argyllshire (parts of). 19s. 3c?. 47. Perthshire. 16s. 3c?. 48. Perthshire, Forfarshire, and Fifeshire (parts of), lis. 49. Forfarshire and Fifeshire (parts of). 5s. 55. Perthshire (Solid and Drift editions). 22s. 3c?. and 25s. 3c?. 56. Perthshire, Forfarshire (parts of). 22s. 3c?. 57. Forfarshire and Kincardineshire (parts of). 10s. 3c?. 57a. Kincardineshire, S.E. corner. Is. 9d. 60. Rum, Canna, Eigg, Muck. 10s. 3c?. 65. Aberdeenshire, Forfarshire, Perthshire (parts of). 25s. 3c?. 66. Kincardineshire, Forfarshire, Aberdeenshire (parts of). 23s. Sd. 67. Kincardineshire and Aberdeenshire (parts of). 5s. 9rf. 70. Inverness-shire (West-Central Skye, with Soay). J19s. 3c?. 75. Inverness-shire, Elginshire, Banffshire, Aberdeenshire (parts of). 19s. 3c?. 76 Aberdeenshire, Kincardineshire (parts of). 13s. 3c?.. 77. Aberdeenshire, S.E. part; Kincardineshire, N.E. corner. 8s. 81. Ross-shiro, S.W. ; Islands of Raasay and Rona, part of Skye. 14s. 9c?. 33 MEMOIRS OF THE GEOLOGICAL SURYEY. SCOTLAND. THE GEOLOGY OP EAST LOTHIAN, INCLUDING PARTS OF THE COUNTIES OF EDINBURGH AND BERWICK. (EXPLANATION OF SHEET 33, WITH PARTS OF 34 & 41.) Second Edition revised and re-written by C. T. CLOUGH, M.A.; G. BARROW; C. B. CRAMPTON, M.B., CM.; H. B. MAUFE, B.A. ; E. B. BAILEY, B.A. ; and E. M. AXDKRKoX, M.A., B.Sc. WITH CONTRIBUTIONS ON THE SILURIAN TABLELAND, by B. K PEACH, LL.D., F.R.K. and JOHN HORNE, LL.D., F.R.S. PUBLISHED BY OKDER OF THE LORDS COMMISSIONERS OF HIS MAJESTY S TREASURY. EDINBURGH : PRINTED EOR HIS MAJESTY'S STATIONERY OFFICE By MORRISON & GIBB LIMITED, At Tanfield. And to be purchased from E. STANFORD, 12, 13, and 14 Long Acre, London: W. & A. K. JOHNSTON, LIMITED, 2 St. Andrew Square, Edinburgh; HODGES, FIGGIS & CO., Grafton Street, Dublin. From any Agent for the sale of Ordnance Survey Maps; or through any Bookseller, from T. FISHER UNWIN, 1 Adelphi Terrace, London, AV.C, who is the sole Wholesale Agent to the Trade outside the County of London. 1910. Price Four Shillings and Sixpence. PliEFACE This memoir describes the geology of the area included in sheet 33 of the one-inch map of Scotland, together with a strip of coast-line on either side of North Berwick in sheet 41, and the coastal belt extending south-east from Dunglass to the base of the Carboniferous Rocks beyond Cockburnspath, in sheet 34. The previous edition of this memoir, published in 1866, was written by H. H. Howell, (Sir) A. Geikie and Dr. John Young. The present edition contains the results of the revision of the Carboniferous areas, which was carried out in 1902, 1903 and 1904 by C. T. Clough, G. Barrow, C. B. Crampton, H. B. Maufe, E. B. Bailey and E. M. Anderson, who have furnished descriptions of their respective districts. Mr. Clough revised the coastal belt between Cockburnspath and Dunbar, and, as district geologist, was in charge of the revision of the rest of the area ; Mr. Maufe revised a small tract between Dunbar and Tynemouth ; Mr. Barrow, the volcanic area of the Garleton Hills and the shore section from Tynemouth round by North Berwick to Gullane ; and Mr. Bailey, the fertile tract south of the Tyne at Haddington and a belt of country flanking the Lammer- muir Hills between Stenton and Fala. In the western district Dr. Crampton completed the revision of an area occupied by the Carboniferous Limestone series from Aberlady south by Salton Hall to Pathhead ; Mr. Anderson, the coal field stretching from Preston- pans south-east by Tranent to Pencaitland ; and Mr. Bailey, a small strip along the coast between Cockenzie and Longniddry. In the preparation of the descriptions of the Carboniferous rocks, the materials published in the previous edition have been freely used, but these have been largely supplemented and, in certain cases, replaced by fuller and more recent information. Perhaps the most important economic result of the recent revision was the discovery by Mr. Bailey and Mr. Tait of a tract of Coal-Measures overlying the Millstone Grit at Port Seton. The area is small, but its occurrence implies the presence of the Carboniferous Limestone coals in ground where they have not hitherto been worked. The Silurian region in sheet 33 was revised by Dr. Peach and Dr. Home, with the assistance of Mr. Macconochie, previous to 1897, and the results of that revision were embodied in the memoir on " The Silurian Rocks of Scotland," published in 1899. No re-examina- tion of that region has since been made, and the description of it is reproduced from that memoir. The glacial and post-glacial deposits have not been systematically revised, but considerable attention has been paid to their develop- ment on the flanks of the Lammermuirs. Before the revision was begun Professor Kendall had devoted some time to the study of the Ill remarkable dry valleys in that region, and his investigations were continued by Mr. Bailey. The results of their observations, which have been published in a joint paper in the Transactions of the Royal Society of Edinburgh, are summarised in this memoir. The chapter on the Petrology of the Carboniferous Igneous Rocks has been contributed by Mr. Bailey, and the rock analyses in connection with the revision of these rocks have been made by Dr. Pollard and Mr. Radley. The lists of fossils in the Palaeontological Appendix have been prepared by Mr. A. Macconochie under the supervision of Dr. Peach. A brief description of the interesting assemblage of organic remains found in the band of oil-shale near Gullane has been furnished by Dr. Peach, and a note on the Vertical Distribution of the Carboniferous Fossils has been contributed by Dr. Lee. The photographs reproduced in Plates I. to VI. and VIII. and IX. were taken by Mr. R. Lunn, and the micro-photographs in Plates X., XI. and XII. by Mr. T. C. Hall. The list of publications relating to the Geology of the district was prepared by Mr. Tait. J. J. H. Teall, Director. Geological Survey Office, 28 Jermyn Street, London, 20th September 1909. CONTENTS CHAPTER I. INTRODUCTION. EAQE Synopsis of Rock Groups, and their Distribution . . 1 Explanation of Horizontal Section . • 4 Glacial Deposits 5 Physical Features . . 5 History of the Landscape ... 8 Geological Environment and Population 10 CHAPTER II. SILURIAN ROCKS. Introduction . . . 12 Arenig, Llandeilo, and Caradoc Rocks . 13 Tarannon . . 19 CHAPTER III. INTRUSIVE IGNEOUS ROCKS IN SILURIAN AREAS. 22 CHAPTER IV. UPPER OLD RED SANDSTONE. Introduction . 25 I. The Sandstones South-East of Fala . . 28 II. The Great Conglomerates . .28 III. Sandstones and Marls, etc., passing up into the Car- boniferous System . . . . . 30 Uneven Surface upon which the Upper Old Red Sandstone was deposited . . 36 CHAPTER V. THE CARBONIFEROUS ROCKS. Introduction .... 37 Comparison of Carboniferous Limestone Series of Scotland and England, based on East Lothian and Northumberland sections . . . .... 37 PAGE East Lothian limestones paralleled with those of Fife . . 38 Calciferous Sandstone Series . . 39 Carboniferous Limestone Series . 40 Coals underlying limestones . 41 Millstone Grit and Coal-Measures 41 CHAPTER VI. CALCIFEROUS SANDSTONE SERIES. District between Dunbar and Cockburnspath 42 Dunbar to Traprain Law .... 51 Area South and West of Haddington 53 CHAPTER VII. CALCIFEROUS SANDSTONE SERIES (cont), North Berwick and Garleton Area. i. the rocks below the volcanic sheets .... 58 (a) Red marls and sandstones, which pass up insensibly into(b) ... . 60 (6) Great mass of green ash . . .63 (c) The limestone horizon . . ... 66 (d) Marls, sandstone, etc., with some pyroclastic material overlying (c) . . . . . . . . .68 CHAPTER VIII. CALCIFEROUS SANDSTONE SERIES {cont.). The North Berwick and Garleton Area (cont.). ii. the volcanic sheets and pyroclastic rocks between them 69 The Basaltic Lavas ... 70 Trachydolerites ..... 74 Trachytes 75 (a) The non- porphyritic and inconspicuously porphyritic trachytes 76 (b) The porphyritic trachytes . . ... 78 (c) The fine compact trachytes ... 79 Inclusions of sediment in the lavas ... .79 Clastic beds associated with the trachytes . 80 in. beds above the volcanic sheets ... 81 Various Isolated Areas op Volcanic Rocks. 1. Oldhamstocks and Fernylee Area . . .86 2. Coast a mile east of Dunbar . . 87 3. Railway cutting south of Broxmouth . 88 4. The Upper Keith Area ... 88 CHAPTER IX. ASH NECKS AND INTRUSIONS CONNECTED WITH THE VOLCANIC EPISODE. Ash Necks ... Stocks, Laccolitbs and Sills connected with the Volcanic Episode the early basic intrusions mugearite trachytic stocks and laccolites North Berwick Law The Bass Rock .... The Traprain Law Laccolite Pencraig and Garvald Laccolites . basic sills and stocks connected with the volcanic centre but later than the pinal surface manifestations Sedimentary Dykes 95 95 97 97 97 97 98 99 99 101 CHAPTER X. PETROLOGY OF THE VOLCANIC ROCKS AND ASSOCIATED INTRUSIONS. Introduction ..... Later Intrusions i. analcite basalts and monchiquites Monchiquites, doubtful Nepheline Basalts and Analcite Basalte Kidlaw Type ......... II. TESCHENITES AND ALLIED ANALCITE OLIVINE DOLERITES Lower Gullane Head Sill ....... Gosford Bay Olivine Analcite Dolerite . ... iii. the craigleith essexite or essexite-dolerite . Basalts op the Effusive Period I. craiglockhart type ii. dunsapie type iii. markle type Trachydolerites ... i. mugearites ii. kulaite Trachytes .... i. the phonolitic trachytes Traprain Law ... Hairy Craig .... Bass Rock ....... North Berwick Law ..... II. TRACHYTES PROPER AND QUARTZ BANAKITES (a) The Quartz Banakites .... (6) The Porphyritic Trachytes (c) Non-Porphyritic Trachytes (d) The Quartz Trachytes . 103 105 105 107 111 114 114 115 116 118 118 119 120 123 123 125 127 128 128 129 129 130 131 131 132 132 132 Vll CHAPTER XL CARBONIFEROUS LIMESTONE SERIES. Lower Limestone Group. PAGE DISTRICT SOUTH-EAST OF DUNBAR . .... 134 AREA FROM ABERLADY TO 1'ATHHEAD .... 138 LENNOXLOVE OUTLIER . .... 146 CHAPTER XII. CARBONIFEROUS LIMESTONE SERIES (cont.). Edge Coal Group. introduction ... . . 147 tranent district . 147 ormiston to pathhead .... . 153 The Hauchielin Coal ... ..... 1 53 The Tranent Splint and Parrot Rough Coals . . . 154 The Great Seam ....... 154 Upper Limestone Group . 154 CHAPTER XIII. MILLSTONE GRIT AND COAL-MEASURE*. MILLSTONE GRIT . .157 LOWER COAL-MEASURES ... . 159 CHAPTER XIV. INTRUSIVE IGNEOUS ROCKS LATER THAN THE COAL- MEASURES 162 CHAPTER XV. FAULTS. THE LAMMERMUIR FAULT THE DUNBAR-GIFFORD FAULT . . . . . THE OLDHAMSTOCKS, INNERWICK AND BROXMOUTH N.N.W. FAULTS FAULTS IN THE CATCRAIG QUARRIES FAULTS ON THE COAST NEAR NORTH BERWICK 165 166 166 167 167 Vlll CHAPTER XVI. PLEISTOCENE AND RECENT. PAGE Stage of Maximum Glaciation .168 Highland Erratics 169 Southern Upland Erratics . . . . . . . .169 Strice and Ice-Moulding ........ 170 Boulders and Boulder Clay . . . . . . .171 Gigantic Erratics . . . . . . . . . .171 Coal near Oldhamstocks . . . . . . . . 172 The Retreat of the Ice Sheet . . . . 172 lammermuir area. Glacial Drainage Channels . . . . . . . .173 The Lammermuir Terrace and the Coastal Spread . 174 Local Glaciers 177 An Upper Limit to possible Submergence . . . .177 Corroms ........ . 178 the garleton area. High Level Channels 178 Low Level Channels 179 Englacial Streams .... . . 180 Raised Beaches 181 upper raised beaches ... ... 181 Prestonpans to Aberlady ........ 181 Aberlady to Tyne Mouth 181 East of Tyne Mouth 183 the 25-ft raised beach 183 Blown Sand 184 Freshwater Alluvium 185 Peat .... .186 CHAPTER XVII. ECONOMICS. Coals. CALCIFEROUS SANDSTONE SERIES . 187 LOWER LIMESTONE SERIES . 187 EDGE COAL GROUP . 188 Hauchielin Coal . 188 Splint and Rough Coals 189 Five-Feet Seam 189 Four-Feet Seam 190 Three-Feet Seam 190 Parrot Coal . . 191 Splint Coal . 191 First Fireclay Seam 192 Great Seam . 192 COAL-MEASURES 193 Fireclays 193 Black-band Ironstone 194 Other B Iinerals . 195 IX Building Stones. pa °e old red sandstone 195 calciferous sandstone series 196 edge coal group 196 igneous rocks 196 Sand . .... 197 Limestones. calciferous sandstone series 197 lower limestone group 197 Road Metal . .198 Agriculture . 201 Water Supply . 202 APPENDIX. pal^eonto logical, prefatory note . ... ... 206 lists of fossils ... . 207 note on fossils from " cheese " bay . . 215 vertical distribution of the carboniferous fossils . . 217 Bibliographical, list of writings 218 INDEX 221 LIST OF FIGURES IN TEXT. Fiu. 1. Section in Papana Water, Garvald ,, 2. Map of Coast near Cove Harbour ., 3. Sketch-map of North Berwick Area 4. Map of Shore near Belhaven Point, west of Dunbar ,, 5. Eye-sketch (Ground-plan) of Neck of Ash. Beach east of Dunbar ........ ,, 6. Composition-Diagram of the East Lothian Basaltic Lavas „ 7. Coast section near Aberlady ..... „ 8. Diagram of the General Vertical Section of the Edge Coal Group in the East Lothian Basin . ,, 9. Map of Port Seton Section . . . . ,, 10. Map showing the direction of the Ice-movement in East Lothian at the period of Maximum Glaciation „ 11. Diagram of " Marginal Footing " .... 17 42 59 89 93 122 139 148 158 168 179 LIST OF PLATES. Plate I. Frontispiece. Bass Rock. An intrusive stock of Phonolitic Trachyte, ,, II. Folded shales (Calciferous Sandstone series). Shore J mile W.S.W. of Weak Law, near Fidra Light- house (to face) 83 „ III. Dunbar Castle Rocks from the south-west. Ruins of Dunbar Castle standing on a mass of basalt in- truded into Upper Old Red Sandstone. On the extreme left is a neck filled with basic tuff. The Dove Eock — a conspicuous stack in the fore- ground—is a plug of basalt filling a neck pierced through Upper Old Eed Sandstone . (to face) 91 Plate IV. LongCraigMiddleLimestone,withZ/^os«rota'. 361. i " The Limestones of Aberlady, Dunbar, and St. Monans," Trans. Edin. Oeol. Soc.', 1905, vol. viii. p. 374. § E. B. Bailey and D. Tait, " On the Occurrence of True Coal Meisures at Port Seton, East Lothian," Trans. Edin. Oeol. Soc., 1905, vol. viii. p. 351. |! Summary of Progress of the Geological Survey for 1903, p. 118. 4 Introduction. Later than the Coal-measures preserved in the district, and probably connected with the great suite of Permo-Carboniferous movements, one may notice the east and west quartz dolerite dykes of Prestonpans and other districts. They are very sharply distinguished in petro- graphical character from the Calciferous Sandstone lavas and associated intrusions. EXPLANATION OF HORIZONTAL SECTION. The general tectonic structure of the solid rocks in the area is illustrated by the diagrammatic horizontal section at the bottom of the map, which is drawn from the coast near Port Seton in a general east-south-easterly direction through the Lammermuirs to Long- formacus. The extraordinary reduplication of the Silurian strata is clearly illustrated by the part of the section south-east of the great boundary fault that lets down the Carboniferous rocks. Prom Longformacus north to the crest of the Lammermuirs the strata exposed at the surface are mainly of Tarannon age, which are repeated by innumer- able inverted folds, whose axial planes dip towards the north-west. Beneath these Tarannon sediments, the shales of the Moffat series (Birkhill = Llandovery, Hartfell = Caradoc, Grlenkiln = Upper Llandeilo, shown by thick black lines) are represented as sharing in this com- plicated system of folding, but they reappear, partly in a modified form, along the northern margin of the tableland. Even in this northern belt the dip of the axial planes of the folds is generally towards the north-west. Hence, in that region, between the crest of the Lammer- muirs and the boundary fault, the Arenig, Llandeilo and Caradoc rocks appear at first sight to succeed or overlie the Llandovery and Tarannon strata. But by means of the graptolite zones it can be shown that this deceptive sequence is due to inversion. The section further shows the relations of the intrusive mass of granite at Priestlaw. At the northern and southern limits of the tableland, in the fine of section, the folded and eroded Silurian rocks are covered unconformably by the Upper Old Ked Sandstone. The Carboniferous rocks are only preserved on the north-western or downthrow side of the Lammermuir fault. They are not known to be affected by any other important dislocation except the Dunbar - Gifford fault, which runs parallel to the Lammermuir fault and has a similar direction of downthrow. Their general angle of inclination is gentle, and is in most places towards the north-west, so that as we proceed in this direction, we pass from the Calciferous Sandstone series into that of the Carboniferous Limestone, and finally reach the small outlier of Millstone Grit and Coal-measures at Port Seton. The Carboniferous Limestone series is represented in its three divisions — the Lower Limestone group, the Edge Coal group and the Upper Limestone group. The Calciferous Sandstone igneous rocks in the line of section are only exposed at the surface in the strips between the Lammer- muir and Dunbar-Gifford faults referred to. They consist of con- temporaneous and intrusive rocks. The former are the continuation Explanation of Horizontal Section. 5 of the Garleton Hill volcanic pile, here greatly diminished in bulk and to some extent split up by intercalation with normal sediment. In consequence of rapid thickening towards the west, the volcanic rocks come very near the surface again at a locality about a mile east of Gladsmuir Church, and have been encountered in boring for water not far from this point. The little outlier of Carboniferous Limestone at Lennoxlove, nearly three miles east of the Gladsmuir outcrop, is so small that it might escape observation unless specially mentioned. The two dykes of quartz dolerite at and near the western end of the line of section run slightly south of west, and their true breadths, taken at right angles to the strike, are not so great as shown. GLACIAL DEPOSITS. The glacial deposits are very widespread but have not been sys- tematically resurveyed, except along the north-western and northern slopes of the Lammermuirs, where the combined work of Prof. P. F. Kendall and Mr. Bailey * has satisfactorily explained the origin of those dry valleys which so long ago attracted attention. f These observers show that the dry valleys belong to an earlier drainage system developed at a time when the margin of the retreat- ing ice sheet stood some distance up the slopes referred to, and that they are of essentially the same character as those already described by Prof. Kendall in other districts. J C. t. c. PHYSICAL FEATURES. A line drawn from the south-west to the north-east corner of the one-inch map 33 divides the district into two nearly equal but very distinct portions. Geologically, this line is the course of the great Lammermuir fault ; geographically, it is the boundary between the Central Valley and the Southern Uplands of Scotland, as developed in this eastern district. The geographical divisions are of course dependent upon the fact that the Lammermuir fault has brought rock groups into juxtaposition with one another which have very diverse capacities for resisting erosion. To the north-west lies an area occupied by sediments of Carboniferous and Old Red Sandstone age with associated igneous rocks. The former have yielded somewhat readily to denudation, and have thus left the more durable igneous masses standing in an isolation which is occasionally very remarkable. To the south-east of the great boundary fault, on the other hand, the predominant rocks are greywackes and shales of Silurian age ; so hardened are these older sediments, by the mountain-making move- ments which preceded the formation of the Old Red Sandstone, that * " The Glaciation of East Lothian South of the Garleton Hills," Trans. Roy. Soc. Edin., 1908, vol. xlvi. p. 1. f John Young, " Geology of East Lothian," Mem. Oeol. Survey, 1866, pp. 63-04. j Special reference should be made to his paper, " On a System of Glacier Lakes in the Cleveland Hills," Q.J.G.S., 1902, vol. lviii. p. 471. See also Prof. P. F. Kendall and H. B. Maufe, " On the Evidence for Glacier-dammed Lakes in the Cheviot Hills," Trans. Edin. Oeol. 8oc„ 1905, vol. viii. p. 226. 6 Introduction. erosion has made comparatively slow progress in its attack upon them, and they now rise abruptly from the general slope of the country lying to the north, and give rise to the long undulating chain of the Lammermuir Hills. In fact, as Sir Archibald Geikie has said, the line of demarcation between the two areas is almost as sharp as the corresponding boundary between the geological colours on the map. The full significance of the contrast can best be gathered from the description given by the same author : " Standing on the north- western verge of the heights, on such an eminence for example as Lammer Law (1733 feet), the spectator sees below him, to the north and west, a rolling plain of woodland and cornfields, dotted with villages and mansions down to the edge of the blue frith, and stretch- ing westwards beyond the crags and hills of Edinburgh. But he has only to turn round to the south and east to look over a dreary expanse of bare hill top and bleak moor — wide lonely pastoral uplands, with scarce any further trace of human interference than here and there a sheep drain or grey cairn. Far away south, beyond the limits of this solitary region, the Eildon Hills, Euberslaw, and all the long line of the Border Hills eastwards to the Cheviots, rise up with a softened outline from the green vale of the Tweed." * Looking northwards once more across the Central Valley the geologist perceives that every one of the many rocky hills, which diversify the plain between the Lammermuirs and the Highlands, consists of igneous material. Each mass stands out in accordance with its ability to resist erosion. The eye wanders to the Pentlands, to Arthur's Seat and across the Forth to the hills of Fife, but back again to East Lothian, where it rests upon the Garleton Hills and the three sister intrusions, Traprain Law, North Berwick Law and the Bass Bock. Without doubt these three intrusions are the most noteworthy landmarks for many a long mile. They all consist of phonolitic trachyte or phonolite, and Traprain Law presents the typical dome-form so well known among rocks of this type in the Auvergne and other districts. Here we can trace the origin of the form, since it proves, in this East Lothian example, to be merely the subterranean contour of the laccolitic intrusion, made manifest now that the arched covering of sediment has been stripped away by denudation. The Garleton Hills are of wider extent, consisting in the main of the trachyte lavas which form the upper portion of the East Lothian volcanic sequence. One cannot help contrasting the rounded ap- pearance presented by these hills with the terraced outlines of the basaltic plateaux of like age in the West of Scotland. The various sediments of the lowland tract appear to differ too little in their relative durability to make independent features pro- jecting above the general cover of glacial drift. In the case of the massive beds of Carboniferous Limestone in the Lower Limestone group, there is, indeed, a suggestion in places of a degraded escarp- ment along their southern outcrop which might perhaps be recognisable enough if the drift accumulations were to be removed. It may not be without significance that the outcrop of the same group in the map to the west is marked by a low undulating ridge separating the East Lothian drainage basin from that of Mid-Lothian. * "Geology of East Lothian," Mem. Geol. Survey, 1866, p. 6. Physical Features. 7 The streams which traverse the lowland portion of the county, for the most part, rise in the hills to the south and unite to form the Tyne Water, which runs through Haddington. The most im- portant tributaries of this system are the Coalston Water, coming from GiSord, and the Birns Water, which joins the main stream farther to the west. Above this point the Tyne Water is of rather insignificant volume, in marked contrast with the size of the valley in which it flows beneath the Pathhead viaduct and through Ormiston and Pencaitland. The valley was in fact fashioned by a much larger river which, in glacial times, was temporarily diverted into the Bast Lothian drainage basin, through a now deserted channel close to Borthwick Castle (one-inch map 32). So far we have considered only the main distribution of lowland and upland as denned by the course of the Lammermuir fault. This simple division persists almost to the North Sea, when a series of cross-faults throw down a coastal strip of Carboniferous strata, thus carrying the lowland district some eight miles south-east across the strike of the Southern Uplands. This encroachment upon the Silurian belt due to cross-faulting must not be confounded with the transverse outcrop of Old Red Conglomerate, shown on the map, which reaches from side to side of the upland district. The contrast of the geological relations in the two cases is as striking as it can be, for the conglomerate lies, where it was formed, filling up an ancient valley of erosion in the heart of the hill country. It may be observed, also, that topographically the conglomerate belongs to the upland and not to the lowland district. When the down-faulted coastal Carboniferous strip is followed south - eastward, a gradually descending sequence is encountered. Near Cockburnspath the Upper Old Red Sandstone emerges at the surface and, farther on, this deposit is seen resting in violent uncon- formity upon the eroded edges of the contorted Silurian strata. The section is classical in the development of geological thought,* and is also noteworthy as the only one in our area which shows the Old Red Sandstone in unfaulted relationship with rocks of Silurian age on the one hand and Carboniferous on the other. The drainage system of this coastal belt is simple in its main outlines. Several independent streams, each with its network of tributaries, start a short distance back in the hill country and reach the coast by valleys which trend in a general north-easterly direction. The Lammermuir Hills can be very shortly dealt with. Their abrupt termination to the north - west has already been noticed. They form an undulating tableland which reaches its maximum eleva- tion in Lammer Law (1733 feet), and is inclined gently towards the south-east. The watershed is situated along the crest of the ridge looking down on to the Bast Lothian plain, and the more important streams therefore drain with the general slope of the tableland, towards the south-east. They gather to form the Leader and the Whiteadder Waters, and so eventually join the Tweed. The northward draining streams have less volume, but their steep gradient has in several cases enabled them to cut picturesque gorges. Most of the valleys- * See references to Hutton and Playfair on p. 26. 8 Introduction. that intersect the tableland are deeply excavated, those which originate around Lammer Law, whichever way they drain, being particularly remarkable in this respect. " The surface of the Lammermuir Uplands is singularly smooth. It is coated with short heath or coarse grass, save where a mantle of peat covers the hollows, or where the streams keep open their channels through the bare drift or hard rocks. Except along the sides of the water-courses, such a thing as a crag is unknown through- out the district. Even a knoll where the rock comes to the surface is rarely seen. It is only along the banks of the brooks and rivulets that the geologist meets with sections of the Silurian strata of which they are composed." * HISTORY OF THE LANDSCAPE. Up to the present we have avoided reference to certain important characters both of the lowland and the upland districts, reserving them for a connected treatment. One cannot wander through a district such as East Lothian without realising how complex a history finds expression in the features of many a simple looking landscape. It is a pleasing task to attempt an analysis in such cases, picking out the modern elements in the topography from the old fashioned, and noting at the same time the changes and development which have affected the latter class. Passing over the modification of the East Lothian landscape by human agency, it may be said that the groundwork of the country re- mains as it stood when the glaciers of the ice age retired, for the only important modifications which have been since accomplished are restricted to the vicinity of the coast. Here one may notice the large tracts of blown sand, especially at Gullane, North Berwick, and Dunbar, and the marine erosion accomplished during the long interval when the land stood about 25 feet lower relatively to the sea than at present. But, as already said, most of the topography of East Lothian is glaciated. The ice scratches have been worn off the exposed surfaces and that is about all. Roughly speaking, we can trace the effects of two distinct phases of glaciation in the features presented by the landscape. There was the period of maximum glaciation when the whole country was covered by a great ice sheet following a course roughly determined by the trend of the Central Valley. To this stage is due much of the flowing contour so characteristic of the scenery of the district as a whole, and also the definite grooving of the rocky framework of the county, especially well seen in the neighbourhood of Haddington. The ubiquitous boulder clay was deposited during this period, and there is reason to believe that the limestone hill at Kidlaw was also carried forward into its present position by the great ice sheet. During this phase of the glaciation both the Central Valley and Southern Uplands were blotted out of the landscape. All was smothered under ice. Then the great ice sheet dwindled, and with the appearance of the southern hills above its surface commenced the * Sir A. Geikie, " The Geology of East Lothian,'' Mem. Oeol. Survey, 1866, p. 6. History of the Landscape. 9 second phase which we have alluded to. This was the period of waning, and its duration seems to have been very prolonged. The geographical conditions were peculiar. There was now a Southern Upland range, but no Central Valley into which the drainage might escape. The streams descending from the hills were checked on arriving at the ice margin'. They were forced in a general way to flow along in the hollow between the ice cliff and the hillside much as rain-water from a house roof is conducted away by side channels. Lakes and overflow channels were of frequent occurrence. This period has left its mark on the scenery in the form of great mounds of sand and gravel stretching round the northern and eastern faces of the Lammermuirs, and in deeply-cut river channels, now often quite dry, which also reach a maximum development along the flanks of this southern range. The valleys themselves are so narrow and trenchlike that in a distant view of the landscape they may easily be overlooked ; but this very feature makes them appear all the more striking when closely approached. Great as were the modifications in topography brought about by the glaciation of the country, it is still obvious that the broader features of the landscape endured until the end of the period of ice, and have thus been preserved to us. The distribution of drift in the present river valleys, as those, for instance, of the Tyne and (xifford Water and the many deep glens of the hills, shows that these hollows pre-existed the glacial period. They speak of prolonged subaerial erosion anterior to the advent of the ice. For a time we know that the land stood much higher than at present, and that the Forth Valley * was excavated by the agency of running water. In fact the Firth of Forth is merely a drowned river valley, and we may con- jecture from analogy with the South of Ireland f that the submer- gence had probably been accomplished before the country was buried under ice. Many features would seem strange to us no doubt if this old, pre-glacial landscape were restored. For example, the various sedimentary groups very probably exhibited distinct features and escarpments, now obliterated as a result of the glaciation of the country. But though the Central Valley was fully developed before the glacial period, it does not appear to have existed in early Tertiary times. Mr. H. J. Mackinder J has pointed to the suggestive manner in which some valleys, e.g. the Tweed-Clyde valley, run right across the hill country. He hints at the possibility that in early Tertiary times, later than the N.W. basalt dykes, the ancient valley feature separating the Highlands and the Southern Uplands was completely blocked with sediment and that the Highland rivers flowed freely into English territory. Subsequent development of the Central Valley, through the comparatively rapid removal of the soft sedi- ments occurring within its borders, broke up this drainage system. The through valleys have, however, been preserved in certain cases, especially where they traversed the harder rocks. Perhaps the railway-pass south of Tynehead, separating the Lammermuir and the * Croll, " On Two River Channels buried under Drift, belonging to a Period when the Land stood several hundred feet higher than at present," Trim*. Oenl. Soc. lidin., 1870, vol. i. p. 330. t Of. Wright and Maufe, " The Pre-Glacial Raised Beach of the South Coast of Ireland," Sci. Proc. Roy. Dublin Soc, 1904, vol. x. partii. pp. 250-324. J " Britain and the British Seas," 1907, p. 132. 10 Introduction. Moorfoot Hills, should be regarded as one of these survivals. It is interesting to notice that, when in the glacial period the Central Valley had again temporarily vanished, now blocked by ice instead of sediment, the ancient drainage system was revived, and for a time a powerful river coursed through the hill country escaping into the Gala Water on the south. These speculations lead to the conclusion that the development of the East Lothian landscape is mainly of Tertiary age, though highly modified during the glacial conditions of early Quaternary times. But we have now to refer to a feature of special interest presented by the hill country. Allusion has already been made to the great transverse valley choked with Old Red Conglomerate, which crosses from side to side of the eastern extension of the Lammermuirs, where the infilling conglomerate stands as high as the surrounding tableland of Silurian greywacke. It is otherwise with Lauderdale (one-inch map 25) and the GifEord and Fala valleys, for here the deposits of Old Red Sandstone age have been in large measure stripped away, revealing once again the ancient topography.* While Lauderdale drains south, the Gifford and Fala depressions appear to be the heads of streams which flowed out northward from the hills. They take us back, probably, to the time when the Central Valley was originated as a structural feature directly influencing the scenery, a true rift valley in fact, recalling that which at the present day includes the Great Lakes of Africa. It must be admitted that this hypothesis regarding the early history of the Central Valley cannot be based upon any evidence included within the limits of the area described. But Dr. Peach has obtained evidence in the adjoining Mid-Lothian district that some important post-Carboniferous faults, which are comparable with the Lammermuir fault, have followed the lines of much earlier pre- Carboniferous disturbances. GEOLOGICAL ENVIRONMENT AND POPULATION. Brief reference may now be made to the influence which the geology of the district has had upon the distribution of the population. The agricultural division of the area into pastoral uplands and arable lowlands has been sufficiently insisted upon. The Lowlands are famous for their high farming, and Haddington is connected with the important improvements in wheat culture,f effected by Shirreff about the middle of the last century. Two particular districts may be noticed where geological conditions have led to specialisation. The first is the coastal strip behind Port Seton, the continuation of the well-known Musselburgh area, where deposits, referred provision- ally to the 100-foot beach, have been turned to account in the develop- ing of a market garden industry. The second is the rich belt of glacial sands and gravels about Dunbar, where potatoes are grown on a very extensive scale. The rocky coasts have furnished convenient sites for small fishing havens. At Port Seton the harbour is situated in the natural hollow * Sir A. Geikie, " Geology of East Lothian," Mem. Qeol. Survey, 1866, p. 26. t Cf. Hugo De Vries, " Species and Varieties," 1906, pp. 107-120. Geological Environment and Population. H excavated in the heart of a small basin of Coal-measures, while the harbour walls are built out on protective wings of massive Millstone Grit. At Cockenzie again, a little to the west, the haven lies sheltered behind an east and west dolerite dyke. Several of the fishing villages have become popular resorts among summer visitors, especially where large tracts of blown sand attract the golfing enthusiast. North Berwick is specially well known in this connection. The coalfield of East Lothian, though not so important as that of Mid-Lothian, supports a considerable industrial population. Some of the seams he at comparatively shallow depths and were consequently worked in very early times. One of the modern pits — Preston Links — is extending its workings under the Forth, where a large virgin field lies ready for future development. The seams worked belong to the Edge Coal group of the Carboniferous Limestone series, and, looking down upon the plain from one of the southern hills, the location of the pits serves as a rough indication of the extent of the outcrop of this group. The coal industry is the only one in which the rocks of the county are extensively worked. Most of the old limestone quarries are now abandoned, and road metal and building stones are in no cases ex- ported, although local needs are for the most part adequately supplied from local sources. e. b. b. CHAPTER II. THE SILUEIAN EOCKS. The strata belonging to the Silurian system occupy the greater part of the area included in the south-east half of the map. They form a portion of the ancient Silurian tableland of the Southern Uplands, and embrace representatives of the various divisions of the system ranging from Arenig to Tarannon time. This part of the tableland, comprising the prominent chain of the Lammermuir Hills, is bounded along its northern margin by the powerful fault already referred to, that brings down the Carboniferous and Old Red Sandstone strata underlying the fertile tract to the north. It is also divided into two unequal portions by a narrow belt of Upper Old Red Sandstone that crosses the uplands from the village of Spott, near Dunbar, south to Longformacus and the south-east corner of the sheet. These rocks have a prevailing strike from south-west to north-east, parallel to the long axis of the tableland, and are usually inclined at high angles. They have been thrown into innumerable sharp folds, the tops of the arches having been removed by denudation, and hence the same beds are repeated across a broad belt of territory. There is little variation in the lithological characters of the dominant types of strata, and fossils are of rare occurrence in the coarser sediments. But, notwithstanding these unfavourable features, the order of suc- cession and stratigraphical relations of the rocks have been worked out by means of the zonal distribution of the graptolites, so firmly established by the researches of Professor Lap worth.* A glance at the map will show that the greater portion of the Silurian area is occupied by strata of Llandovery and Tarannon age, extending from the southern border of the map northwards to the crest of the Lammermuir Hills south of Garvald. They form part of the great central belt of Tarannon rocks — about twenty-five miles in width, — which is such a prominent feature in the geological structure of the Southern Uplands. Rising from underneath these Upper Silurian sediments along their northern margin, we find representatives of Caradoc, Llandeilo, and Arenig rocks, repeated by innumerable folds, and containing bands of black shale, charged with graptolites, characteristic of some of these divisions in the Moffat region. They occupy the whole of the area between the base-line of the Tarannon strata and the great fault that bounds the northern margin of the Silurian tableland. In this region, as elsewhere throughout the northern belt of the uplands, there is evidence of the change in the nature of the sedi- mentation as we pass from the central Moffat region northwards to the margin of the tableland, to which attention was first directed by * A detailed account of Professor Lapworth's researches is given in the Geological Survey Memoir on " The Silurian Rocks of .Scotland," 1899, chap. ii. 12 Arenig, Llandeilo and Caradoc Rocks. 13 Professor Lapworth.* The Glenkiln black shales (Upper Llandeilo) with their zonal forms are represented at various localities in the Lammermuir Hills in association with the underlying radiolarian cherts (Lower Llandeilo, Upper Arenig). Nowhere within the limits of the map have the Arenig lavas been recorded, but they appear not far to the south-west in the Hope Burn in the Moorfoot Hills, beneath the Glenkiln black shales and radiolarian cherts. f The Hartfell black shales (Lower Caradoc) with some of their characteristic graptolites also occur, but they are succeeded by grey- wackes, flags, and a large development of grey shales with an occasional band of fossiliferous conglomerate (Channelkirk), which indicate a marked departure from the phase of the Barren Mudstones (Upper Hartfell group, Upper Caradoc) to be found in the Moffat region. Still more noteworthy is the disappearance of the Birkhill shales (Llandovery), but this feature is characteristic of the northern margin of the Tarannon belt throughout the uplands. In certain localities along this horizon between the Lammermuir Hills and the Wigtownshire coast-line, thin dark seams or films, charged with Birkhill graptolites, are intercalated in grits, conglomerates, grey- wackes, and shales. These modifications furnish conclusive evidence of the transport of coarse sediment during Llandovery time from the ancient land area which lay to the north-west of the Silurian sea. But though of special interest as throwing light on the conditions of deposition, they increase the difficulty of fixing the northern limits of the Upper Silurian area of the central belt. ARENIG, LLANDEILO AND CARADOC ROCKS. In the sequel, descriptions will be given of those sections which have furnished fossils characteristic of the Glenkiln and Hartfell black shales of the Moffat sequence. These occur partly on the southern and partly on the northern slopes of the Lammermuir Hills. Kelphope Burn and its tributaries. — The Kelphope Burn drains the southern declivity of the Lammer Law (1732 feet) and the adjoining heights, traversing in its course the lower divisions of the system and the overlying Tarannon rocks. An interesting section of the Glenkiln black shales may be seen in a tributary of this burn which joins the main stream from the west, about half a mile north from Kelphope shep- herd's house. About 600 yards up this tributary, after passing grey shales, the observer encounters a small exposure of flinty black shales on the east bank, from which the following forms have been collected : — Didymograptus superstes Lapw. Nemagraptus gracilis (Hall) [Cceno- graptus auct.]. Nemagraptus pertenuis (Lapw.) [Ccenograptus auct.]. Dicellograptus sextans (Hall). Dicellograptus moffatensis (Carr.). Diplograptus (Mesograptus)e/. foliaceus (Murch.). Diplograptus (Amplexograptus) anti- quus (Lapw.) [Climaoograptus auct.']. Glossograptus hincksi (Hopk.). Lasiograptus bimucronatus (Xich.). Climaoograptus bicomis (Hall). Climacograptus scharenbergi Lapw. Dicranograptus ramosus (Hall). Cryptograptus tricornis (Can.). * See " The Moffat Series," Quart. Jour. Geol. Soc, vol. xxxiv. p. 323 ; and " The Ballantrae Rocks of South Scotland and their place in the Upland Sequence," Geol. Ma;/., New Series, Dec. iii. 1889, vol. vi. p. 59. t " The Silurian Rocks of Scotland," 1899, p. 268. 14 Silurian. The specimens of D. swperstes are especially abundant and well preserved. A few yards farther up the stream, on the same bank, a small exposure of black shales has furnished specimens of Climacograptus caudatus in fine preservation, together with Diplograptus cf. foliaceus and Corynoides in the same seam, belonging to the Lower Hartf ell group. On the opposite bank, the black shales have afforded Diplograptus cf. foliaceus, Corynoides calicularis, and fragments of Climacograptus. Grey barren shales succeed, which are truncated by a fault, followed by much smashed black shales veined with quartz. About 10 yards farther up some black shales have yielded — Glossograptus hincksi (Hopk.). Climacograptus bicornis (Hall). Climacograptus peltifer Lapw. Climacograptus scharenbergi Lapw. Cryptograptus tricornis (Carr.). Dicranograptus ramosus (Hall). Diplograptus (Mesograptus)c/. foliaceus (Murch.). These shales are succeeded by grey shales with dark strains, and after a blank in the section, black shales with the grey cherts occur, while in a side rivulet, that joins this tributary from the west, the black shales again appear. Friar's Nose, Lammerlaw Burn. — At the Friar's Nose, where the Kelphope Burn bifurcates, its north-east branch, named Lammer- law Burn, furnishes evidence of the existence of the Pleurograptus linearis zone in the Moffat Shales. Greywackes and shales appear at intervals in the stream as far as a point about 700 yards north from the Friar's Nose, where a fine exposure of black platy shales runs along the banks of the stream for a distance of 100 yards. On the north-west bank, and within two or three feet of the grey shales, the following assemblage of fossils characteristic of the highest zones of the Hartfell black shales was obtained : — Leptograptus flaccidus (Hall). Leptograptus capillaris (Carr.). Diplograptus (Mesograptus) cf. foliaceus (Murch.) Diplograptus (Orthograptus) quadri- mucronatus (Hall). Climacograptus sp. Dicellograptus forchhammeri (Gein.). Dicellograptus elegans (Carr.). Dicellograptus pumilus Lapw. Dicellograptus morrisi (Hopk.). Neurograptus fibratus Lapw. [Retio- lites auct.J. Pleurograptus linearis (f'arr.). A peculiar feature of this section is the abundance of Leptograptidce in certain seams close to the grey shales. On the south-east bank, a few yards farther up, Climacograptus, Diplograptus cf. foliaceus, arms of Dicellograptus and Dicranograptus have been found. In a small tributary which drains the Eed Scar Rig, black shales appear with grey cherts pierced by a dyke. A few yards above its foot Climacograptus bicornis occurs in dark seams in grey shales. Again, the north branch of the Lammerlaw Burn lays bare stained grey flints, and the south branch, black shales and black flints. Headshaw Burn (Head of Lauderdale). — Important evidence is obtained in this stream to show the relation of the Hartfell black shales to the overlying sediments. About a mile to the north of New Channelkirk, at the northern margin of the map, the Headshaw Burn is joined by the Windycleuch Arenig, Llandeilo and Caradoc Rocks. 15 Burn, which, opposite a bend in the road, exposes thin platy black shales, including thin worm-piped barren ribs with black shale partings. From the shales the following fossils were obtained : — Dicellograptus sp. i Diplograptus (Mesograptus) cf. foliaoeus Corynoides curtus Lapw. (Murch.) Corynoides sp. Retiolites sp. Climacograptus bicornis (Hall). Above this outcrop the fossiliferous black shales graduate upwards into flaggy shales with dark seams, followed by grits and mudstones, all much reddened. Below it a blank occurs in the section, till, at a point 70 yards above the culvert, the grey worm-piped ribs with black shale partings are again laid bare and contain Diplograptus cf. foliaceus, Climacograptus bicornis, and Corynoides. In the Headshaw Burn, above its point of junction with the Windy - cleuch Burn, a succession of grits, greywackes, flags, and shales, all much reddened and repeated by folding, may be traced up the stream. Between the foot of the Windycleuch and the foot of the second small tributary of the Headshaw from the north, two arches bring up repre- sentatives of the Hartfell shales. The one farther down the .stream only reveals the higher sandy bands with thin leaf-like dark scams, the other, about 500 yards up from the foot of the Windycleuch, near the junction of a second stream from the north, shows alternations of thin hard flinty ribs with black shale partings. The black seams have yielded Diplograptus cf. foliaceus and Climacograptus. Farther up the stream, jointed grits and shales appear, and at a point 700 yards from the foot of Windycleuch, much crushed black shales seen on the north bank contain Climacograptus, Diplograptus cf. foliaceus and Cori/noides. From this point upwards for a distance of 100 yards in an almost continuous section, grey sandy ribs alternate with black shale seams. At a point about 800 yards from the foot of Windycleuch, the bands occurring on the south side of the stream yield Plenro- graptus linearis, dip to the south, and display certain distinctive characters, for they here consist of grey sandy siliceous ribs with black shale partings from an eighth to an inch thick. From these partings the following fossils have been obtained : — Pleurograptus linearis (Garr.). Climacograptus bicornis (Hall). Diplograptus (Mesograptus) cf. folia- ceus (Murch.) Dicellograptus sp. Retiolites sp. Corynoides calicularis Xirh. Higher in the valley these beds pass outwards into more sandy bands with dark strains, which are succeeded by stained grits and shales. Where the burn takes a bend to the north, and where a stone fence crosses the stream, the Hartfell shales are repeated along another arch composed of two minor compound folds, the more northerly of which has afforded the following forms : — Pleurograptus linearis (Carr.). Dicellograptus sp. Climacograptus bicornis (Hall). Diplograptus (Mesograptus) cf. folia- ceus (Murch.). Corynoides calicularis Nich. On the slope of the Headshaw Hill, black shales with radiolarian cherts in the centre are traceable on the surface by means of debris. Grey shales appear on the south side of this exposure, followed by grit. Southwards, beyond a development of grey shales of Lowther 16 Silurian. type, the large quarries on the hill-slopes E.N.E. of New Channelkirk farmhouse have been opened along a band of conglomerate and grit. The conglomerate only a few feet thick, forms a ridge in the quarry, bounded north and south by a coarse grit which has been excavated as building-stone for dykes. The conglomerate is somewhat peculiar in character, the matrix being a grit in which small fragments of chert, black shale, grey shale, abundant quartz-grains, etc., occur. In fresh fracture the rock has a greenish tint. Perhaps its most notable feature is the occurrence in it of lenticular masses of grey shale, which are bent and folded with the conglomerate, and, so far, have yielded no fossils. The black shale fragments, however, furnish specimens of Climacograptus caudatus in excellent preservation, Diplograptus cf. foliaceus, Corynoides, Dicellograptus. The blocks containing these forms must have been derived from the Climacograptus caudatus zone. Another piece of black shale, probably from the Glenkiln horizon, was found to contain Diplograptus antiquus, Diplo- graptus cf. foliaceus, Glossograptus hincksi, Climacograptus scharen- bergi. Numerous arms of Dicellograptus were also found on another slab. Several pebbles have likewise been recorded, one of gabbro, and others of fine-grained felsitic rock with porphyritic felspars, the latter being well rounded, and averaging from three to four inches across. On the north side of the quarry, the junction between the shales and the grit is visible. It is obvious that this conglomerate points to local elevation and erosion of the Arenig volcanic rocks, radiolarian cherts, black shales, and other sediments. Northwards, the beds consist of grey shales or mudstones, containing small flattened nodules of lime- stone, which differ in character from the limestone of Wrae and Winkston. Soutra Hill. — In the Brothershiels Burn, at the south-west margin of the map and along the crest of Soutra Hill, two bands of dark 6r black shales are associated with greywackes and shales. About half a mile to the north of these outcrops the Arenig cherts and black shales are again visible near the sources of the Armet Water, in rivulets upwards of 200 yards E.N.E. of Gilston Peel. hammer Law. — The radiolarian cherts and black shales rise on two anticlinal folds at the head of the East Burn — a tributary of the Birns Water. In the outcrop on the east side of the coomb-shaped hollow at the head of this tributary the strata are much shattered and veined with quartz. These Moffat shales are here associated with decomposing brown sandy shales of the Lowther type, with occasional bands of grit. Again, on the scar at the head of the western tributary of the Kidlaw Burn, on the north-west slope of the Lammer Law, black shales appear, with a strike to north and south, and in one instance to N.N.W. and S.S.E. These strata form small arches surrounded by brown decomposing shales. They have as yet furnished no fossils. Some of these black shale outcrops may belong to the same system of folds as those already described in the tributaries of the Kelphope Water, though the beds cannot be traced continuously between the two areas. At least one of the black shale bands on the south slope of the Lammer Law appears to be traceable by means of debris across the moory watershed at the head of the Hope's Water, where the Arenig cherts and black shales appear in a crushed and shattered Arenig, Llandeilo and Caradoc Rocks. 17 condition among brown sandy shales, pierced by dykes of acid igneous rock. The chief point of interest in the Hope's Water section is the remarkable system of folding, for although the black shales are exposed at a great height on the slope, they rapidly disappear under brown sandy shales, owing to the pitch of the folds being steeper than the declivity of the ground. That these sandy shales in all probability represent, in part at least, the Barren Mud- stones of the Moffat region is rendered highly probable, if not certain, by the fact that, in th3 Blinkie Burn — which rises from the north side of Lammer Law — one of the black shale bands has yielded graptolites which elsewhere are associates of Pleurograptus linearis. Here, near the source of the stream, in an exposure of black sandy shales, the following among other forms were collected : Diplograptus (Orthograptus) quadrimucronatus, Diplograptus cf. joliaceus, Dicellograptus elegans, Corynoides calicularis. From its lithological character and included fossils, this band is probably identical with the Pleurograptus linearis zone of the Friar's Nose. Farther down the same stream, the Moffat series appears twice, about half a mile to the S.S.E. of the Castles. The dark flinty bands are the lowest beds visible in the upper exposure, while the Arenig cherts are seen in the lower. The black shales associated with the latter contain Lasiograptus bimucronatus and Climaco- graptus bicomis. Here the strata are much reddened owing to the proximity of the Upper Old Red sandstones and conglomerates. The general dip of all the Silurian strata in this portion of the Lammermuir chain is towards the W.N.W., and hence the same beds must be constantly repeated by isoclinal folds. Papana Water. — Farther to the north-east, in that portion of the Lammermuirs drained by the streams south of the village of Garvald, evidence is obtainable of the occurrence of the Arenig cherts and Glenkiln black shales. By far the best section of these zones is to be found in Papana Water, about two miles south of the village of Garvald. In this stream, above the point where it is crossed by the fault that brings the Upper Old Red Sandstone (c 3 , Fig. 1) in contact with the Silurian rocks, shattered and reddened greywackes and shales extend for a distance of about 100 yards. These are followed by a band of coarse conglomerate (C), which forms a waterfall. This rock C*H -SO <.v a, r rjj 18 Silurian. contains well-rounded pebbles of greywacke, grey quartzite like that of the Perthshire Highlands, granite, and grey cherts, with fragments of grey and black shale. From the last named, specimens of Climaco- graptus were obtained. Southwards, the conglomerate is followed by grey shales, with a band of black shale which contains Diplograptus cf. foliaceus. For the next 150 yards there is a constant repetition of black shales, grey shales, and two bands of radiolarian cherts ; the beds being much shattered, folded, and traversed by faults. Still farther south, grey mudstones succeed, and are followed by black shales with seams of grey shales, visible in the bed of the stream for a distance of 40 yards. At the southern limit of this broad mass of black shales the radiolarian cherts (C) reappear, truncated on the south side by a reversed fault that brings them in contact with grey- wackes and shales, and followed on the north side apparently in normal order by black shales (2 1 ), enclosing Didymograptus superstes, Diplograptus cf. foliaceus, and Climacograptus . From another point in the same broad mass of black shales (2 1 ) the following typical list of Glenkiln fossils was collected : — Didymograptus superstes Lapw. Nemagraptus pertenuis (Lapw.) [Cceno- graptus auct."]. Nemagraptus gracilis (Hall) [Cosno- graptus auct.]. Nemagraptus gracilis, var. surcularis (Hall). Thamnograptus typus (Hall). Thamnograptus scoticus Lapw. Climacograptus scharenbergi Lapw. Climacograptus bicornis (Hall). Cryptograptus tricornis (Carr.). Diplograptus (Mesograptus) cf. folia- ceus (Murch.). Diplograptus (Amplexograptus) anti- quus (Lapw.) [Climacograptus auct.]. Diplograptus (Glyptograptus tere- tiusculus (His.), var. euglyphus Lapw. Lasiograptus bimucronatus (Nich.). Dicranograptus ramosus (Hall). Dicellograptus sextans (Hall). Dicellograptus patulosus Lapw. Discina portlocki Oein. It is probable that the Lower Hartfell black shales (3 11 ) are also represented in this section, though too much crushed to yield fossils. For the next 300 yards, beyond an exposure of shattered grits near the black shales, the strata consist of grey and brown sandy shales repeated by constant folds (3, Fig. 1). Where the stream divides, black flinty shales occur, from which no fossils were collected owing to their shattered condition. Grey shales of the Lowther type (3) again succeed, and are traceable southwards for a distance of 500 yards. Here grey grits supervene which are provisionally regarded as marking the northern base line of the Llandovery and Tarannon rocks, while the grey and brown shales are viewed as the equivalents of the Barren Mudstones of Moffat. Proceeding eastwards, the observer finds several folds of the Moffat black shales and Arenig cherts in a tributary of the Papana Water about half a mile to the east. One exposure yielded the following Glenkiln assemblage : — Didymograptus superstes Lapw. Nemagraptus gracilis (Hall) [Coeno- graptus auct.]. Lasiograptus bimucronatus (Nich.). Dicranograptus ramosus (Hall). Corynoides curtus Lapw. Climacograptus bicornis (Hall). Diplograptus (Amplexograptus) anti- quus (Lapw.) [Climacograptus auct.] Cryptograptus tricornis (Carr.). Dicellograptus sextans (Hall). Dicellograptus moffatensis (Carr.). Discina portlocki Oein. Arenig, Llandeilo and Caradoc Rocks. 19 Thorter Bum, near Garvald. — This stream furnishes evidence of the easterly prolongations of the folds of the Moffat series. For nearly 600 yards south of the fault between the Upper Old Red Sand- stone and the Silurian region, the rocks exposed in the Thorter Burn consist of crushed dark and grey shales and gritty greywackes ; the latter being in places conglomeratic. Just above the point where the burn bends at a right angle, flinty black shales occur, too much shattered to yield fossils ; these are followed by jointed grits and shales for a distance of 150 yards, where they are in turn succeeded by crushed black flinty shales, affording specimens of Diplograptus cf. foliaceus, Climacograptus bicornis, Cryptograptus tricornis, Dicello- graptus. Next come grey mudstones with dark seams like the Barren Mudstones of the Moffat region ; but soon grits appear which dip to the N.N.W. at 37°, and form a series of cascades. These are followed by a development of black shales that occupy the stream for a distance of fifteen yards, and are traversed by dykes of acid igneous rocks. At one point on the east bank, the following fossils occur in thin black shale partings between the black flinty ribs, the graptolites and shells being in fine preservation : Lasiograptus bimucronatus, Diplograptus cf. foliaceus, D. euglyphus, Dicellograptus, Climacograptus bicornis, Corynoides calicularis, Discina portlocki, Acrotreta nicholsoni. These black shales are immediately followed by greywackes, an< i then by a broad belt of grey sandy shales of the Lowther type, which are admirably exposed on the banks of the stream. The general dip of the strata in the Thorter Burn is towards the N.N.W. , so that the beds must here again be isoclinally folded. Sauchet Water, south of Stenton. — The remaining outcrops of the Moffat shales on the northern slopes of the Lammermuirs are to be found in tributaries of the Sauchet Water, about a mile and a half south of Stenton. Small exposures of black shales with black flinty ribs appear in two tributaries close to the fault that brings the Upper Old Red Sandstone in contact with the Silurian rocks. One of the outcrops in the main tributary north of Stonypath yields Diplograptus cf. foliaceus, and Dicellograptus ; but fossils are difficult to obtain owing to the shattered condition of the rocks. The black shales are here succeeded by grits and greywackes, which are followed southwards by a great development of grey sandy shales. In a little tributary of the Sauchet Burn, about a quarter of a mile south of Deuchrie farmhouse, a thin dark seam in these grey shales afforded Diplograptus cf. foliaceus, Dicellograptus complanatus, and Climacograptus sp. This evidence is of importance, as it proves beyond doubt that the grey shales are the equivalents of the Barren Mudstones of Moffat. TAEANNON. Reference has already been made to the disappearance of the Moffat type of Birkhill shales along the northern base line of the Upper Silurian rocks of the central belt, and to the occurrence on that horizon of thin seams of black shale or dark films, charged with some representatives often in a dwarfed condition of the prolific Birkhill fauna, which are interleaved in coarse sediments. Such intercalations have been detected within the limits of the map, in Soonhope Burn, on the southern slope of the Lammermuir 20 Silurian. Hills, at a point about two miles S.S.B. of the top of Lammer Law and about ten miles west of the village of Longformacus. Here dark slates and grits, either vertical or highly inclined and repeated by- folding, appear in the stream. The dark seams have yielded specimens of Monograptus tenuis, Climacograptus scalaris, var. normalis, and a dwarfed representative of Climacograptus. The base line has been drawn immediately to the north of these exposures, beyond which occurs a development of slates and grey sandy shales with occasional grits and a band of conglomerate (Channelkirk) that have been corre- lated with the Lowther shales and have been regarded as the equivalent of the Barren Mudstones (Upper Caradoc) of the Moffat region. Not far to the south-west of the limits of this map similar evidence has been obtained in the Ladyside Burn in the basin of the Heriot Water. In such cases the base-line may be laid down with comparative certainty. But from the Soonhope Burn north-eastwards to the north slope of the Lammermuirs south of Stenton, where representa- tives of the Lower Birkhill fauna have not yet been detected, the boundary has been drawn between the Llandovery and Tarannon grits to the south and the grey sandy shales of Lowther type to the north, which, as already indicated, have yielded the zonal form Dieellograptus complanatus (Upper Caradoc) in a small tributary of the Sauchet Burn. The large loop-like folds of the Tarannon base line on the northern declivity of the Lammerrmiir Hills south of Garvald illustrate the reduplication of the strata by lateral compression (see Sheet 33). It is probable that such interosculation of the Caradoc and Llandovery strata along the boundary line between them has been developed on a minute scale, though it cannot be definitely established by means of palseontological zones. Further evidence of the plication of the strata is to be found in the sections exposed in the Dye and Faseny Waters and their tributaries, where there is a frequent change in the direction of the dip, the inclination being sometimes to the north-west and sometimes to the south-east. The dominant type of strata represented within the Tarannon area in this sheet, is that of massive grits and greywackes (Queens- berry Grits), which locally merge into conglomerates ; the higher sub- division, comprising the Hawick Bocks, has not as yet been recognised. Sometimes partings of shale are interleaved in the grits, and, in places, there are bands or zones of grey and red fissile shales. Though Tarannon fossils have not yet been found in these rocks within the limits of the map, they have been obtained in the Whelplaw Burn — a tributary of the Leader Water — at a locality about one mile from the southern margin of Sheet 33, and four miles north from the village of Lauder. About 400 yards up this stream from Longcroft farmhouse (Sheet 25), brown mudstones, weathering spheroidally, have furnished specimens of Monograptus crispus, M. exiguus, M. lobiferus, M. attenuatMS, M. pandus* It is worthy of note that, at a point about the centre of the southern border of Sheet 33, on the ridge between Jock's Burn and Wester Burn, the north-east termination of the isoclinal fold of the Moffat Shales of Barnscleuch Burn is represented on the map. This arch is * A larger list of Tarannon graptolites has been obtained from the shales at Old Cambus beyond the limits of Sheet 33. See " The Silurian Rooks of Scotland," p. 209. Tarannon. 21 of special interest as it brings to the surface, in the midst of Tarannon strata, representatives of the Glenkiln-Hartfell and Birkhill groups, with some of their characteristic graptolites.* These zones are visible in the Earnscleuch Burn, and must pass underneath the overlying Tarannon rocks towards the north-east before reaching the Wester Burn. b. n. p., j. h. * See "The Silurian Rocks of Scotland," p. 196, where the section in Earnscleuch Burn is described. CHAPTER III. INTRUSIVE IGNEOUS ROCKS IN SILURIAN AREAS. The Silurian strata included within this sheet are pierced by two small masses of granite which are of the same age as the large granite intrusions in the south-west part of the tableland beyond the river Nith. One of these forms the triangular mass of Priestlaw, where the Faseny Water and the Whiteadder join ; the other appears on Cockburn Law, in the south-east corner of the map. In the last edition of this memoir,* Sir A. Geikie called attention to the fact that the Priestlaw mass had long been known to Scottish mineralogists, and had been visited by Playfair, Hall, Jameson, Boue, etc.f It covers about a square mile of ground, and the rock is laid bare at various points on the banks of the Whiteadder and of its tributary, the Faseny. In places it decomposes into a yellowish or greenish sand with nodular lumps or balls of solid rock imbedded in the loose matrix. The relations of the granite to the Silurian strata are not well seen except in the Faseny Water, where they are exposed about a mile up from its junction with the Whiteadder. The evidence there obtained leaves no room for doubt that the mass is intrusive, for it truncates the grits and shales which have been altered by contact metamorphism, and it is further observable that numerous dykes of porphyrite and other igneous materials, which are apophyses of the main mass, penetrate the altered sediments. The rock varies considerably in texture and composition through- out its extent. In places it is a biotite granite, and by the addition of hornblende it merges into a hornblende-biotite -granite — a common type in different parts of the mass. Three specimens from the Priestlaw intrusion have been sliced and examined by Dr. Teall, who thus describes their petrological characters : " The first (No. 7808), J from the Faseny Water, Priestlaw, is a hornblende-biotite-granite ; the second (No. 7809), J from the same stream, near the edge of the mass, is a more basic rock than the preceding one, with porphyritic, zoned plagioclase in a micro-granite aggregate of biotite, hornblende, felspar, and quartz. It might almost be termed a hornblende-biotite- porphyrite, but the ground mass is somewhat coarser in grain — more granitic — than in the typical porphyrites. The specimen is interest- ing as showing that the physical conditions under which the margin of the Priestlaw mass consolidated, approximated to those under which the porphyrite dykes were formed. The third specimen (No. 7810), also from the edge of the mass in the Faseny Water, is a quartz- * " Geology of East Lothian," p. 15. f Playfair, "Illustrations," p. 328; Jameson's "Mineralogy of Dumfries," Ap- pendix; Boue, "Essai Geologique surl. l'Ecosse," p. 94; Ogilby, Mem. Wer. Soc. h vol. i. 126 ; Hay Cunningham, ' Geology of the Lothians." p. 101. % Numbers in brackets refer to slides in the Geological Survey Collection. 22 Granite Masses and Dykes in Silurian Areas. 23 augite-biotite-diorite. This rock differs from the quartz-biotite- hyperites only in not containing hypersthene. The pale-green augite (malacolite), which occurs to the almost entire exclusion of hornblende, and the general structure of the rock are precisely similar to the corresponding features in the hyperites." * The granite of Cockburn Law in the south-east corner of the map is the westward continuation of the mass on Stoneshiel Hill (Sheet 34). The portion included in Sheet 33 covers about a quarter of a square mile of ground. Similar types to some of those already described are to be found in this intrusion, as, for example, biotite granite, hornblende-biotite-granite, and fine grained more basic varieties near the margin. Within the area of Upper Old Red Sandstone south of Longformacus appears the prominent intrusive mass of Dirrington Great Law (1309 feet), which is prolonged southwards to Hallywell Rig in Sheet 25. Though surrounded by Upper Old Red strata, this mass is of older date than the deposition of these sediments, for near the head of the Stonypark Burn on the S.S.W. side of Hallywell Rig (Sheet 25) the sandstones and conglomerates dip at angle of 5° to the south-east, and contain fragments derived from this intrusion. While probably of the same general age as the plutonic masses of Priestlaw and Cock- burn Law, the rock is not granitic but consists of felsite or trachyte. Immediately to the east of Dirrington Great Law there are two small patches of felsitic rock at the margin of the map that are con- nected southwards with the igneous mass of Blacksmill Hill in Sheet 25, the relations of which to the Upper Old Red strata are similar to those just described in the case of the Dirrington Great Law intrusion. In his treatise f on " The Ancient Volcanoes of Great Britain," Sir A. Geikie has introduced a horizontal section drawn across the three Dirrington Laws, and showing their relations to the older Paleozoic sediments. They are represented as isolated bosses penetrating the Silurian strata and covered unconformably by the Upper Old Red Sandstone. A glance at the map will show how the Silurian strata are traversed by numerous dykes of igneous material, which, as a rule, are traceable for no great distance. Usually they run in a north-east and south- west direction — that is in accordance with the general strike of the greywackes and shales, but in some instances their trend is N.N.E., and even about north, in which case they obliquely cross the bedding planes of the sediments. There can be little doubt that they are of the same general age as the plutonic masses of granite. No micro- scopic sections of these dykes have been prepared, and it is thus impossible to present a satisfactory classification of them, but from specimens collected at various times it would appear that they include representatives of porphyrites, lamprophyres, and felsites. In the south-east corner of the map a dyke of dolerite has been traced for a mile and a half in a direction nearly east and west from Oatleycleuch to Stoneshiel Hill in Sheet 34. It traverses alike the Silurian rocks and the granite mass of that hill. Sir A. Geikie sug- gested that it should probably be ranked with the other late north- west and south-east or east and west dykes which are found over the * "Silurian Rocks of Scotland," p. 625. t " Ancient Volcanoes of Great Britain," vol. i. p. 291. 24 Intrusive Igneous Rocks in Silurian Areas. whole country.* Recent microscopic examination of this rock has confirmed the accuracy of the latter part of his reference, for it has been found to be a quartz-dolerite similar in character to the east and west dykes of the Midland Valley which are now regarded as of late Carboniferous age. b. n. p., j. H. * "Geology of East Lothian," p. 17. CHAPTER IV. UPPER OLD RED SANDSTONE. INTRODUCTION. The Old Red Sandstone is almost confined to the south-east side of the Dunbar and Gifford fault, which crosses the map, near the middle, in a south-west and north-east direction ; but a small area also occurs on the north-west side, near Dunbar. On the south-east side of the fault, the formation occupies a con- siderable proportion of the strip, often about two miles broad, between this line of displacement and the parallel Lammermuir fault. On the south-east side of the latter, it forms several detached areas, the largest of which runs from Spott, in a nearly southerly direction, to the south-east corner of one-inch map 33. These isolated areas afford excellent proof of the violent unconformity between the Old Red Sandstone and the underlying Silurian rocks, since the former are composed to a large extent of fragments derived from the latter, while they fill up old valleys carved through the same. " It was in this part of Scotland that the earliest observations were made on the true character of some of the ancient revolutions of the crust of the earth.* The highly-tilted Silurian strata and the gently-inclined sandstones which rest on their edges, furnishing as they do proofs of great terrestial change, caught the eye of Hutton, and in his hands, as well as those of his associates Playfair and Hall, they were made the means of establishing some of the fundamental principles of geology. The district which thus became classic ground to the students of this science lies chiefly along the shore from the mouth of Dunglass Burn to St. Abb's Head.f This bold coast, rising in a long line of cliff from the sea margin, forms one vast natural section, not more instructive in its geological aspects than impressive from its wild and lonely grandeur. Hutton and his biographer, Playfair, visited it in company with Hall, and they have both left a record of the excursion. After examining part of the rocks on the shore, they proceeded along the base of the cliff by boat to search for the junction of the red sandstone and inclined Silurian beds, or ' schistus.' ' At Siccar Point,' J says Hutton, ' we found a beautiful picture of this junction washed bare by the sea. The sandstone strata are partly washed away, and partly remaining upon the ends of the vertical schistus ; and in many places points of the schistus strata are seen standing up through among the sandstone, the greatest part of which is worn away. Behind this again we have a * Sir A. Geikie, " Geology of East Lothian," Mem. Geol. Survey, 1866, p. 19. t One-inch map 34. % Within one-inch map 34, but the name is not given in the new edition of this map. It should have been placed close to Craig Taw. 26 Upper Old Red Sandstone. natural section of those sandstone strata containing fragments of the schistus.' "* Hutton at the time was dealing with broad principles and for him the Lower Old Eed Rocks of St. Abb's Head, the Upper Old Red Sandstones of Siccar Point and the Carboniferous strata of Bast Lothian were all alike " secondaries " in contradistinction to the " primaries " or " schistus " of the Lammermuirs. When men's thoughts came to turn, in this country, more to the correlation of the great rock groups, it was found that the red sandstones generally underlie white sandstones, being interposed between the latter and the greywacke of the hills, and therefore they were placed, by some authors,f in the Old Red Sandstone, which had by this time been separated in England from the overlying Carboniferous system. Charles Maclaren J took up a somewhat different attitude ; he was struck, as so many observers have been since his time, with the con- formable passage upwards from the red sandstones of the Lothians into genuine Carboniferous rocks. He saw no break in the succession upon which to base a classification, but still he recognised the desirability of subdivision ; thus he introduced the term Calciferous Sandstone to cover, not merely what we understand as belonging to that group, but also our Upper Old Red Sandstone series and our Lower Limestone group ; he states that the Calciferous Sandstone " corresponds in its lower part to the old red sandstone of the English Geologists ; in the upper, to their ' Mountain limestone.' " The term, however, fell into comparative disuse until Sir Archibald Geikie § reintroduced it in- the sense in which it is now employed, with such restrictions, in fact, that the group has been deprived at base and summit of the two distinctive portions upon which the name was founded. To Stevenson || of Dunse we owe the first discovery of fossil fishes in the sandstones of this district, which has definitely placed these beds in the Upper Old Red Sandstone series as defined by Murchison, since the characteristic form Holoptychius was obtained. He also made a careful map ^f of the district, tracing the outcrop of the great conglomerate which had aroused Hutton's enthusiasm long ago, when he came on it by accident in the banks of the Oldhamstocks Burn. In addition to this, he recognised the faulted character of many of the junctions, where it had been passed over in silence by earlier observers. With the completion of the Ordnance Survey of the district de- tailed mapping became possible, and the work of Sir Andrew Ramsay, Mr. Howell, and Sir Archibald Geikie naturally marked a great advance upon that of their predecessors. Sir Archibald Geikie has given us a clear account of the manner in which the distribution of conglomerate * " Theory of the Earth," 1795, vol. i. p. 458. See also Playfair, "Illustrations," 1802, § 191. " Works," 1822, vol. iv. p. 78. Hall, " On the Vertical Position and Convolutions of certain Strata and their Relation with Granite " Trani Hem Soc. Edin., 1815, vol. vii. pp. 84, 162. ' J ' f Milne Home, Map in the " Memoir on the Mid- Lothian and East Lothian Coal Fields," 1839. J "Geology of Fife and the Lothians," 1839, p. 09. § " The Geology of Eastern Berwickshire," Mem. Oeol. Survey, 1863, p. 41 || " On the Geology of Cockburnlaw, and the adjoining District in Berwickshire " Trans. Roy. Soc. Edin., 1849, vol. xvi. p. 33. f " On a Gap in the Greywacke Formation of the Eastern Lammermuirs filled by Old Eed Sandstone Conglomerate," Q.J.G.S., 1850, vol. vi. p. 418. Introduction, 27 and sandstone within the Lammermuirs reveals the erosion features of an ancient land surface. A twofold grouping of the strata into upper sandstones and lower conglomerates was adopted, and, although the latter have never yet yielded fossils, the two groups were considered as part of the Upper Old Red Sandstone series. Their reasons for holding this view with regard to the great con- glomerate which runs across the eastern part of the hills were that it rests upon and wraps round intrusive rocks of Lower Old Red Sandstone age and contains fragments of the same, while in character it agrees with the thin conglomerates which frequently serve as the local base of the fossiliferous series. These questions will be referred to in the sequel. Sir Andrew Ramsay suggested a glacial origin for the conglo- merates, but no evidence in support of this view has been brought to light during subsequent researches. Since the completion of this first survey Mr. Goodchild has made a study of the sandstones exposed in the Coast section, and his views regarding the desert origin of much of these accumulations will be referred to subsequently. Dr. Peach has also added a new area to that included previously in the Upper Old Red Sandstone. His lines, which appear in Sir A. Geikie's general map of Scotland, have been retained, with some modifications, resulting from the recent revision of the area. Mr. Maufe has found that the Cornstone group crops out in the Dunbar cliffs to the north of the Dunbar-Gifiord fault. Also, the great conglomerate has been discovered for the first time upon the north side of the Lammermuir fault (or perhaps more strictly speaking between two branches of the same) and under circumstances which suggest a threefold in place of the twofold division of the group hitherto adopted. The map shows three areas occupied by the conglomerate : first, the great belt which crosses the eastern portion of the hills ; secondly, a small area lying between two faults to the south of Garvald ; and thirdly, an outlying patch upon the top of the plateau south of Fala. In the eastern area the conglomerates appear to be separated from the sandstones which occur still further east, between Oldham- stocks and Siccar Point, by two powerful dislocations, the combined downthrow of which must be towards the east. Here we may accept the old reading that the conglomerates are older than the sandstone above mentioned. The conglomerate in the small area bounded by two faults, south of Garvald, must be older than the sandstones to the north which doubtless pass westwards, though the junction is not exposed, beneath the overlying Carboniferous strata. But it is to be noted that this area of conglomerate is also brought into contact by faulting with sandstones to the south. The latter are the deposits preserved in the ancient Gifford valley, and as they come into direct contact with the Silurian rocks, with never more than a foot or two of con- glomerate between, it is obvious that they must be older than the strip of conglomerate, at least forty feet thick, which has been faulted against them to the north. Further west again, to the south of Fala, we find sandstones in the valley bottom as at GifTord, and conglomerates resting on the 28 Upper Old Red Sandstone. top of the plateau — a distribution quite in accordance with the view that the Gifford and Fala sandstones were formed before the great conglomerates. The threefold division now suggested for the Old Ked deposits of Bast Lothian is as follows : — III. Sandstones and Marls, etc., passing up into the Carboniferous strata ; II. Great Conglomerates ; I. Sandstones south-east of the Lammermuir Fault, near Gifford and Fala. Both the bottom and top divisions when in contact with the Silurian rocks may exhibit very thin local conglomerates at their base. Although the lowest division has not as yet yielded fossils, still its lithological resemblance to the top division supports the view that it, and the overlying great conglomerates, belong to the Upper Old Red Sandstone. I. THE SANDSTONES SOUTH-EAST OF GIFFORD AND FALA. Danskine Burn furnishes a very good section of the Gifford valley deposits. The unconformity at the base is well exposed, the lowest member of the series being a conglomerate which consists of rolled greywacke fragments and closely resembles a coarse river gravel. It is only a few feet thick and impersistent, for though seen again to the south-west in Newlands Burn and Hopes Water, it is absent to the north-east in the burn that flows down from Snawdon. The rest of the section exposed in Danskine Burn consists of a monotonous series of red sandstones with subordinate red micaceous marls. In the valley south-east of Fala, a more variegated set of sand- stones and grits, both red and speckled white occur. Small fragments of chert in the coarser grits have probably been derived from the Arenig rocks of the Southern Uplands. A basal conglomerate is only seen around a little inlier of Silurian rocks exposed in the Dean Burn, and is there no more than a foot or two in thickness. II. THE GREAT CONGLOMERATES. The thick conglomerates " have been derived from the waste of the Silurian hills, and contain fragments of all the rocks of which these hills are composed, with the exception of the greenstone dykes.* For the most part they are made up of fragments of the hard Silurian grits and greywackes, with pieces of different porphyritic felstones, granite, syenite, jasper, quartz, etc. Near the granitic mass of Cockburn Law the conglomerate abounds in pieces of granite. The pebbles vary in size up to blocks sometimes two feet in diameter, and it is worthy of notice that throughout a large part of the district, as in the hills to the south of Dunbar, they are not thoroughly rounded like ordinary beach shingle, but more or less subangular with an inter- mixture of rounded and to some extent of angular fragments. They are imbedded in a somewhat scanty red ferruginous gritty paste. The tenacity with which the pebbles adhere to each other varies considerably, and in this way it gives rise to some picturesque forms of scarp and ravine. Sometimes, where some infiltration has bound * Sir A. Geikie, " Geology of East Lothian," Mem. Oeol. Survey, 1866, p. 20. The Great Conglomerates. 29 a mass of the conglomerate more firmly together than the surrounding portions, a fantastic peak or pillar has been left alone. On other occasions the same effect, on even a more remarkable scale, is pro- duced by a dyke of greenstone, which, with its sides cased in a rough coating of conglomerate, stands up as a giant column, or runs along the face of a cliff as a perpendicular wall. These features are well seen in the ravines of the Hardens Hills to the west of Dunse, and in those to the south-west and west of Oldhamstocks. Save in these water-courses, however, the area occupied by the conglomerates is as smooth and tame in outline as that of the Silurian hills. . . After our united survey of these hills it was the conviction of my colleague, Mr. Howell, and myself that the total depth of conglomerate at the thickest part could not well be less than 2000 feet." The conglomerate extends with these characters southwards from Spott, " but when it advances to the base of the Dirrington Hills it begins to get finer in texture and more sandy, passing up at length into a fine felspathic sandstone, in which fragments of white or pink felstone like that of Dirrington Law are abundant." * Conglomerates and sandstones extend south-westwards from Dirrington Law till " circling round the southern margin of the Lammermuir Hills the conglomerate ascends the valley of the Leader as far as New Channel Kirk, near which, as will be immediately pointed out, it presents some interesting relations to the overlying sandstone series. Continuing up this valley we find the conglomerate reappear in the Headshaw Burn at Carfrae Common, whence it spreads out on either hand as an outlying cake which has here been laid down on the broad flat crest of the Lammermuir chain. This outlier, although not united with the conglomerate of Lauderdale on the one side, nor with that of Fala on the other, is manifestly a mere fragment, and descends into the heads of the valleys in such a way as to show that here the Old Eed Sandstone once stretched com- pletely across the Lammermuir chain. This outlier, however, is the only remnant of that ancient conglomerate covering still left upon the top of the ridge." The "interesting relation" between conglomerate and overlying sandstones to which Sir Archibald Geikie refers is an unconformity between the two which he describes and figures as occurring south of Annfield Public House, Lauderdale. Such a relation does not appear to be general, for Dr. Peach states that in most of the places where the sandstones and conglomerates are seen together they inter- digitate with one another. That some of the sandstones within the conglomeratic area are of considerable thickness is shown by a recent bore, put down by the Town Council of Dunbar, near Halls, about two miles south-west of Spott. After passing through 71£ ft. of drift, this bore pierced 41J ft. of hard red sandstone, overlying 187 ft. of conglomerate, the base of which was not reached. The position of the bore is only 1000 ft. east of the nearest exposure of Silurian strata, and it seems probable that the slope of the pre-Old Red surface was here at least one in three. A feature of the conglomerate is its even bedding which is often shown by thin bands of sandstone, or, where these are absent, by * " Ancient Volcanoes of Great Britain," 1897, vol. i. fig. 70, p. 291. 30 Upper Old Red Sandstone. the arrangement of the flatter stones. Despite the coarseness of the deposit there are few if any signs of tumultuous assortment or current bedding. No special description is necessary of the small faulted strip south of Garvald, as its characters are in perfect agree- ment with those of the beds already described. III. SANDSTONES AND MARLS, ETC., PASSING UP INTO THE CARBONIFEROUS SYSTEM. After the accumulation of the great conglomerates just described, there was a return to conditions similar to those which led to the formation of the lower sandstones and marls of Division I. The upper sandstones and marls included in Division III. probably origin- ally covered the whole area occupied by the conglomerates, and also in many places overlapped upon the Silurian plateau where the latter still remained uncovered. At the close of the Old Eed Sandstone period there can be little doubt that the Lammermuirs had com- pletely disappeared for a time under the gathering load of deposit, though at present, owing to the long history of subsequent folding, faulting, and denudation, we find the strata of Division III. preserved only in isolated areas. Despite the great thickness of these strata, only a rough twofold division has been found possible, into an upper group with cornstones and a lower without. The whole series seems to be extremely variable in the various areas which we shall now proceed to describe in order from south-east to north-west. The first of these areas borders the great belt of conglomerate in the south-east corner of the map, and is in part bounded by a line of fault. " On the west side of this fault the rock is wholly conglo- merate ; on the east side it is chiefly red sandstone, with layers of red shale or marl.* At two points along the south-west side of the line of fault a little knob of Lower Silurian strata may be seen rising from under the conglomerate, and flanked on the north-east side by the sandstones and marls. One of these protuberances, called the Knock Hill, lies immediately to the west of Castle Mains ; it is made up of greywacke and shale, in some parts very much broken and metamorphosed. The other is seen in the bed of the Mill Burn between Kidshielhaugh and Burnhouse. It covers a space of only a few yards where, from under the conglomerate, some beds of purple greywacke, with pebbly bands, are seen dipping toward W.N.W. at an angle of 50°. These two exposures of greywacke and shale re- present, perhaps, the remnant of what was the margin of the Silurian region during the deposition of the conglomerate. The effect of the fault would thus be to depress the Silurian region on the north-east side, so as to let in, in a wedge shape, the sandstones and marls which were formed at a later time against a higher and of course newer margin, which still remains. On this explanation we can understand why the conglomerate should end off so suddenly against a given line, for that would be approximately the edge of the old Silurian land ; and why the lenticular strip of sandstone and marl should come in sharply between the borders of the conglomerate and the flank of the Silurian Hills." e. b. b. A somewhat similarly situated area of red sandstones and marls * Sir A. Geikie, " Geology of East Lothian," Mem. Geol. Survey, 1866, p. 23. Sandstones and Marls, etc. 31 extends eastwards from Oldhamstocks to the coast at Siccar Point. Two powerful N.N.W. faults pass close by the former place, and the Upper Old Red Sandstone deposits which are found upon their east side differ in a remarkable manner from the coarse conglomerates which occur on their west side. The relations of these two sets of beds are not clear. No true conglomerates comparable to those on the west are anywhere seen on the east, and in the coast section between Cove Harbour (Fig. 2, Chap. VI.) and Siccar Point * the sand- stones in the lower part of the formation are generally finer in grain and more mixed with clayey shales than those in the upper part. In the section 250 yds. N.N.E. of St. Helen's Church red clay shales and dirty white sandy beds are seen within a few feet of the Silurian rocks, and they contain no pebbles of the latter. The two faults referred to may be regarded as parts of one great dislocation which let down in the space between them a series of higher beds. No beds belonging to the Upper Old Red Sandstone are seen in this space, but most of it is drift covered, and it is quite possible that some do occur. On the east side of the eastern fault the country is also drift covered to a large extent, but it is probable that, close alongside the dislocation, the Upper Old Red Sandstone extends, with one slight interruption due to the faulting in of some Carboniferous beds, for more than two miles. But eastwards the breadth of the Upper Old Red Sandstone area must become rapidly less, partly in consequence of a north-easterly dip, and partly owing to two large faults with downthrow to the south and south-east, which are both exposed in Berwick Burn. It is probable that at Hoprig the breadth is somewhat less than a mile, and that between this place and Siccar Point the outcrop now forms a belt, about three quarters of a mile broad, which runs in an E.N.E. direction at right angles to the general dip, with Silurian rocks on the south side and Carboniferous on the north. The following section gives, in descending order, the sequence of strata in the coast section between Cove Harbour and the west end of the Silurian inlier at Siccar Point :— Ft. /. Deep red sandy clay with deep red calcareous lumps projecting on the weathered face . . . . . . . . . . . . 5 c. Red and white sandstones with deep red calcareous lumps and streaks, some of which cross the bedding planes, and also tolerably numerous thin chert lenticles, from one to three inches thick and of a creamy colour. These beds are disturbed by numerous small faults which do not seem to affect the overlying strata, and may be of contemporaneous character . . . . . . . . . . . . . . 15 d. Dirty white and brick red sandstones with dark red calcareous parts, cornstones, either fine or coarse in grain and very abundant. Gener- ally they include many small clastic jgains of quartz, but some are finer grained and of a creamy colour, OTfciot unlike some of the Car- boniferous cementstones. Occasionally triey form vertical seams and also lumps, like pebbles, which may have been formed by the break- ing up of a lower bed. Most of the clastic grains in the sandstones are about the size of a mustard seed and consist of quartz or felspar, but small pebbles of quartz nearly an inch long are occasionally observed, and in one place a piece of quartz felsite about half that size was de- tected. The weathered faces of some of the sandstones are spotted * Both these localities are within one-inch map 34. 32 Upper Old Red Sandstone. Ft. with small round projections, which possess a poikilitic structure and are composed of clastic grains embedded in a cement of calcite 300-350 c. Brick red sandstones with clastic grains about the size of mustard seed, together with occasional bits of red sandstone and galls of greyish green and red shale. Small poikilitic calcareous lumps, about the size of a hazel nut or walnut, are common, but no regular cornstones occur in this group . . . . . . . . . . ■ • 300-350 b. Brick red sandstones of varying grain but generally somewhat finer than the sandstones in the overlying division . . . . . . 120 a. Brick red soft false-bedded sandstones, with clastic grains generally less than a mustard seed, mixed with a greater proportion of deep red sandy shales and clays, in which thin buff-coloured seams are also frequent. These basal beds lie upon the Silurian greywacke . . 300 It will be seen that the total thickness of the above six divisions is estimated to be 1100 ft., but the exposures are divided by the wide sandy bay north of Pease Mill, and it is possible that there is some hidden fault which misses out some beds between the bottom of division c and the top of division b. Divisions d, e, and / may be conveniently classed together as the Cornstone group. On the ground it seems impossible to draw a definite line between the top beds of the Cornstone group and the bottom beds of the suc- ceeding Cementstone group of the Carboniferous system, and there is nothing to suggest that any erosion or overlapping, or great lapse of time, took place between the formation of these two sets of beds. A specimen of the chert (10691) from division e has been examined microscopically, but showed no organic structures. Scales of Holoptychius nobilissimus have been found in abundance in division d, and also to a less extent in c and a. The highest bed in which they have been observed is about 30 ft. below the top of d. A few words may here be added with regard to the work of others in elucidating the manner of origin and the history of these deposits. Dr. Sorby, while treating of sands with quartz chemically deposited on the surface of the grains, states that good examples of the early stage of the process are seen in the Old Red Sandstone of Cockburnspath. * Mr. Goodchild subsequently advanced the theory that the corn- stones, and also certain allied deposits in the Lower Carboniferous rocks, are chemical precipitates formed from the action of decom- posing organic matter on solutions of sulphate of lime, during a period of transition from desert conditions to a more congenial climate. f He also states that the lower subdivisions of the Upper Old Eed Sandstone of Tweedside is more largely composed of desert sand grains than the upper.J and refers to the sandstones near the foot of Pease Burn as containing grains of quartz which have had their surfaces more or less rounded and roughened by prolonged drifting before the wind, and subsequently coloured by staining from the New Eed Sandstone, which according to his belief formerly spread over the rocks in question. § * " Presidential Address," Q.J.O.S., 1880, vol. xxxvi. p. 62. f "The Geological History of Lower Tweedside," Proceedings Oeol. Assoc London 1903, pp. 118-120. %0-p. et'fc, p. 118. § "The Scottish Ores of Iron,'' Trans. Edin. Geol. Soc, 1903, vol. viii pp 204- 206. Sandstones and Marls, etc. 33 Good inland sections situated in the same area are afforded by the Oldhamstocks and Berwick Burns. The top of the formation is repeated three times in the course of the last mentioned stream, owing to faulting, and it is also well seen in Oldhamstocks Burn, but in neither of them can any cherts be found. Cornstones of much the same character as those in the coast section are abundant, and the lower divisions of the formation do not seem to be exposed. In Oldhamstocks Burn, on the north side of the east and west fault, about 400 ft. of beds, all containing cornstones, are exposed. Just below the top in this burn is a breccia, with a somewhat ashy aspect, which includes pieces of white sandstone and greyish green shale as much as an inch long. A somewhat similar breccia is also seen, on perhaps a slightly lower horizon, in Berwick Burn, about 350 yds. north-west of Hoprig. Another but much smaller isolated area of these deposits occurs some miles to the north-west of Oldhamstocks and is partially exposed in the railway cutting south of Broxmouth. Soft red and white false-bedded sandstones are here seen dipping steeply west over beds of the Cementstone group of the Carboniferous formation, and although no remains of Holoptychius have yet been found in them there is little doubt that they belong to the Upper Red Old Sand- stone, and that they have been overturned owing to movements of compression. Most of the clastic grains in these beds consist of quartz or felspar and are smaller than mustard seeds. In the upper half small red calcareous lumps are seen here and there, but in much less abundance than in the coast section east of Cove Harbour ; some of these cornstones were noticed in a bed of purplish clay-shale about 90 ft. below the top of the series, and others in sandstones more than 300 ft. lower. No chert lenticles were anywhere observed. Sandstones similar to those in the cutting are also seen for a little distance on either side, and have been quarried, and inclusive of these there is evidence for a thickness of about 1000 ft. Upon the coast east of Dunbar red sandstones are exposed on the south-east side of the Dunbar-Gifford fault ; they are separated from any other rock exposures in a south-easterly direction — the direction of their strike — by an interval of about a mile, and as many of these exposures consist of rocks differing considerably from those on the coast and composed to a large extent of breccias crowded with pieces of Silurian rocks, it will be convenient to describe the coast section by itself. It seems not impossible that it may be separated from the exposures referred to by some obscure branch of the Oldhamstocks and Innerwick N.N.W. fault. Most of the beds consist of Indian red soft false-bedded sandstones in which the clastic grains are rather less than a mustard seed, but with these are mixed occasional yellowish sandstones and deep red and greenish-grey shales. The red shales are often spotted with oval or round spaces, half an inch or an inch in length, in which the colour is pale green. The dip is generally slightly south of west and varies from 18° to 58°, but at the eastern end, near the fault which divides this series from the Cementstone group, the beds steepen and finally become vertical or are even reversed. The section is nearly half a mile long, and after making allowance for some folding along a north and 3 34 Upper Old Red Sandstone. south axial plane inclining east, the total thickness is estimated to be about 1500 ft. without reaching a natural top or bottom. Kemains of Holoptychius have not yet been found in spite of prolonged search. In the lower portion of the series, the shaly beds are more abundant than in the upper, and the sandstones also are generally rather finer grained and more free from calcareous parts. The upper beds, especi- ally those within 150 ft. or so of the top, contain a number of lumps and streaks of cornstone, but not in such abundance as the upper divisions of the formation east of Cove Harbour. In these upper beds, also, angular fragments an inch or two long, are occasionally seen, consisting of fine grained red sandstone, with which galls of clay- shale occur, but not, so far as our observation goes, any fragments of Silurian rocks. c. t. c. Passing on to the north-west side of the Dunbar-GifEord fault we find massive, false-bedded, coarse grained sandstones with corn- stones exposed in the shore-sections between Dunbar Castle (Plate II.) and the big red tuff west of the town. In the small bay on the eastern margin of this tuff, the top beds of the Cornstone group are conform- ably overlain by the lowest beds of the Cementstones, which contain Carboniferous fossils. The line dividing the formations is drawn at the top of the uppermost sandstone containing cornstones and at the base of the shale underlying the lowest cementstone band. The full section is tabulated in Chapter V., where details of the Carboni- ferous rocks are given. The rocks here classed as Upper Old Sandstone have failed to yield organic remains in spite of repeated search, but their lithological resemblance to the Upper Old Red Sandstone of the district warrants their inclusion in the Old Red • formation. The cornstones, as well as the cementstone bands are stained bright red by iron-oxides, which have been referred generally to haematite, but which J. G. Goodchild believed to be turgite.* It will be shown in the sequel that in the case of the Cementstones the iron-oxide must be present as a stain, which has most probably been supplied from above. The red colour of much of the Cornstone group of this district may thus be due in part to staining introduced after Carboniferous times, and Goodchild believed it was derived from a former covering of New Red Sandstone. A fault traverses the shore in a north and south direction immedi- ately to the east of the small patch of Carboniferous rocks, and brings up the Cornstone group with an eastward dip. The Cementstone group does not, however, come on again in that direction, because another fault passing near the Dove Rock again throws up the beds to the east. The sandstones with cornstones are well exposed in the western wall of the Castle Rocks, and the shales and sandstones poorly exposed immediately east of the igneous rock may be basal Carboni- ferous beds. A thick series of red, purple, and yellowish, speckled sandstones, the last sometimes with calcareous pustules on the weathered surfaces, but without true cornstones, occupy the space on the shore between the Harbour and the Dunbar-Gifford fault. In spite of repeated search no fossils have been found as yet in these beds, but on account * " Scottish Ores of Iron," Trans. Edin. Geol. Soc, 1903, vol. viii. p. 206. Sandstones and Marls, etc. 35 of their lithological resemblance to the Stenton sandstones and to the beds low down in the Cornstone group between Cove Harbour and Siccar Point, already described, they have been placed with the Upper Old Red Sandstone. They are affected by numerous faults, mostly of small size, and their continuity is greatly interrupted by several necks filled with volcanic tuff. The quartz grains of the sandstones are rounded, but often appear angular on account of a secondary growth of quartz in optical continuity with the original grain. The new growth is clear and colourless, and shows crystal faces, whilst the boundary with the original grain is marked by a reddish-brown stain of ferric oxide. Subangular grains of felspar are common and belong to microcline, perthitic orthoclase, or an acid plagioclase. Amongst the heavier constituents zircon and rounded grains of brown tourmaline are abundant. There also occur rutile, garnet, hornblende, and anatase. The red colouring matter, haematite or turgite, is attached to other grains in minute spherules, which in the case of the speckled sandstones are clustered into spots. h. b. m. Sandstones and marls of the Upper Old Red Sandstone extend inland for a distance of nine miles between the Lammermuir and the Dunbar-Gifford fault. Their junction to the west with the Lower Carboniferous rocks is completely obscured by drift, and although they are exposed in several good sections it has not been found possible to establish any general stratigraphical sequence in them. Mr. Macconochie has, however, obtained a scale of Holoptychius nobilissimus, determined by Dr. Traquair, from a fallen block in the river gorge near Whittinghame, and has thus confirmed the hitherto accepted view as to the age of these rocks. A sandstone which is sometimes pebbly and calcareous, very like that of Dunbar, is exposed in the Sauchet Water at Stenton and along the shores of Pressmennan Loch. Elsewhere red sandstones predominate, but thick red marls, with only very subordinate sandstone partings, are also seen in various places : for instance, at the bend of the Spott Burn, a mile south- west of Spott ; in the Whittinghame Water, half a mile north-east from Whittinghame House ; and in Papana Water, south from Garvald Fort. These exposures seem to indicate the existence of at least one marl group with a thickness not under two hundred feet. Further west, again, between the same two faults, another con- siderable area is occupied by rocks which probably belong to the Upper Old Red Sandstone. The most interesting exposures within this area occur in the Humbie Water south of Highlee and in the tributary burn entering this water at Humbie Mill. The series is largely composed of soft purple sandstones containing cornstone concretions and occasional nodules of white chert. White and lilac clays also containing cornstone concretions occur with these sand- stones. In the Humbie Water two continuous bands of cornstone cross the stream, one being three-feet thick. A feature of the series is the frequent occurrence of sandstone bands containing numerous angular fragments of cornstone. Lithologically they bear an equal resemblance to the breccia bands in the Cementstone group, near Cockburnspath, and to others in the Upper Old Red Sandstone of the Craigmillar district, near Edinburgh. The correlation of these Humbie beds with the Cornstone group of the Upper Old Red Sand- 36 Upper Old Red Sandstone. stone was first suggested by Mr. Macconochie. It must be admitted that the sections exposed differ considerably from any others in the county, but they can be paralleled exactly with those in the Corn- stone group north of Ballagan, Stirlingshire. UNEVEN SURFACE UPON WHICH THE UPPER OLD RED SANDSTONE WAS DEPOSITED. As already noticed, the distribution of the Upper Old Red Sand- stone south of the Lammermuir fault enables us in some measure to reconstruct the ancient topography of the district. Thus the con- glomerates of the eastern area and of Lauderdale * mark the course of deeply eroded valleys which, at any rate in the latter case, drained south towards the Merse of Berwick. Dr. Peach has traced similar valleys in the Cheviot Hills leading towards the same depression from the other side and choked with conglomerates consisting of the local rocks. Then, again, the red sandstones to the south of Griff ord partially fill in the head of an ancient corrie open to the north, but dominated to the south by the summits of the present watershed. Also, the red and speckled sandstones and grits which occur in the Soutra valley south-east of Fala are similarly situated and are bounded to the south by a continuation of the same line of hills. The ridge, moreover, which now separates the Soutra and Lauder valleys is capped by a cake of conglomerate, showing that the present relief at this point had been determined before the formation of some portion of the upper division of the Old Red Sandstone. In the earliest stages of the obliteration of this ancient topography, of which we have cognisance, most of the material which began to choke the valleys was of a sandy nature perhaps derived from a distant source ; a later epoch followed, during which local erosion greatly increased and massive conglomerates collected in the valleys and on the gentler slopes as a result of the acceleration of denudation in the higher parts of the area ; finally, there was a return to the con- ditions which led to the accumulation of sand, and the whole range became smothered in a thick deposit of red sandstones and marls which passed upwards through the Cornstone group into the over- lying beds of the Carboniferous system. E. b. B. * In one-inch map 25. CHAPTER V. THE CARBONIFEROUS ROCKS.* Introduction. As already indicated, the one-inch Sheet 33 is traversed by two ad- jacent parallel faults, the Dunbar-Gifiord fault and the Lammermuir fault, the latter south-east of the former, which divide it into two nearly equal parts. Both these faults strike from south-west to north-east and have a downthrow to the north-west, and the area on the north-west side of the Dunbar-Gifiord fault consists almost wholly of Carboniferous rocks or of associated igneous rocks which are chiefly of a contemporaneous character. The long stripe between the two faults varies from one to two miles in breadth, and the south- western portion is formed partly of Carboniferous strata and partly of Upper Old Red Sandstone, together with a few small patches of igneous rock. In a general description it may be said that over most of the area on the north-west side of these faults the dip is west or slightly north of west, so that as we go from the mouth of the Tyne towards Preston- pans we pass from lower to higher divisions of the Carboniferous formation. But there are many exceptions to this arrangement, as, for instance, on the south-east side of the anticline which strikes from Traprain Law, in the south-west, to Belhaven Bay, on the north-east, f and the symmetry of the structure is also interfered with by the different development of the igneous rocks in different parts. South-east of Dunbar another much smaller area of Carboniferous rocks has been preserved on the north-east or downthrow side of a powerful fault which strikes in a N.N.W. direction. This area extends along the coast for rather more than seven miles, to a bay a little east of Cove Harbour, in one-inch map 34. The chief groups, Calciferous Sandstone, Carboniferous Limestone, Millstone Grit and Coal-Measures, into which the Carboniferous rocks are divided, have been already shown in Chapter I. The line adopted as the base of the Carboniferous Limestone series of Scotland in the district east of Dunbar is the base of the Long Craig Lower Limestone, and it is tolerably clear that Mr. Gunn correlated the Long Craig Limestone with the Eelwell Limestone of North North- umberland, and the Five Yards Limestone of Weardale and Teesdale.J The Five Yards Limestone lies considerably above the Hardraw Scar Limestone — the band taken by Phillips § as the lowest of the * Most of this chapter was written in 1904, before the publication of Dr. Vaughan's papers. Reference to the latter is made in the Appendix. f See " Geology of East Lothian," Mem. Geol. Survey, 1866, p. 31. j " Correlation of the Carboniferous Rocks of England and Scotland," Oeol. Mag., 1898, p. 342. Also Trans. Edin. Oeol. Soc, 1899, vol. vii. p. 361. § "Geology of Yorkshire," part ii. p. 37 (1836 edition). 38 The Carboniferous Rocks. Yoredale limestones, and this in turn lies above the Great Scar Lime- stone of Ingleborough and Melmerby. A cursory examination of certain sections on the Northumberland coast disclosed to us various facts which strengthen Mr. Gunn's correlation, for instance, the Skateraw Lower Limestone * has much the same lithological character as the little limestone which comes between the Acre and the Eelwell Lime- stones.f The bedding planes of the Eelwell Limestone, also, are generally uneven and lumpy, and remind us of those in the Long Craig Upper and Middle Limestones, while those in the Acre are more even and like those in the Skateraw Middle Limestone. The Edge Coal group has been shown by Mr. Gunn % to be on the horizon of the Lickar coals of Northumberland. These coals come above the top of the Yoredale series of Philips, but both they and the overlying limestones are included in the Carboniferous Lime- stone series in the North of England and in Scotland. Dr. Wheelton Hind has written a number of articles § in which he refers to the relations of the Carboniferous Limestone series of Scotland to that of England. Before Mr. Gunn published his correla- tion, Dr. Hind had made a tabular statement in which he placed all the Calciferous Sandstone series below all the Carboniferous Lime- stone series of England, and afterwards, in his review of Mr. Gunn's correlation, he again states that the fauna of the Calciferous Sandstone series contains very few species which go up into the Carboniferous Limestone series. The differences between these two authorities are probably, however, not so great as they might seem at first glance, for Dr. Hind admits in one of his articles that the fossils characteristic of the Carboniferous Limestone of England are occasionally found in thin beds in the Calciferous Sandstone series of Fifeshire, and that the Carboniferous rocks in Scotland give good evidence for the truth of Barrande's theory of " colonies," according to which theory the fauna, owing to an unsuitable environment, migrated and lived on in some adjoining area ready to return when more favourable con- ditions obtained. It is to be noticed, also, that Dr. Hind has placed the Carbonaceous group (Scremerston) of Northumberland in the zone of Productus giganteus and P. cor a, a zone which also includes the Carboniferous Limestone series of Scotland, and there is no doubt whatever that the stratigraphical position of this Carbonaceous group lies considerably below the horizon taken as the base of the Carboni- ferous Limestone series of Scotland. c. t. c. When Mr. Gunn identified the Skateraw and Longcraig Limestones of Dunbar with the Acre and Eelwell Limestones of Lowick, he estab- lished a correlation between the Northumberland and Scottish sections generally. In regard to the East Lothian Basin and Fife, our know- * For the position of this limestone, and of the Long Craig Limestones refer to Chapter XI. f " Geology of Belford, Holy Island, and the Faroe Islands," Mem. Geol. Survey, 1900, p. 36. % Geol. Mag., 1898, p. 347. § "On the Subdivisions of the Carboniferous Series in Great Britain," Geol. Mag. 1897, p. 159 and 205. " The Life Zones of the Carboniferous Deposits of Europe," Geol. Mag., 1898, p. 61. " The Subdivisions of the Carboniferous Series in Great Britain and some of their European Equivalents," Trans. Edin. Geol. Soc, 1899, vol. vii. p. 332. " On Mr. Gunn's Correlation of the Carboniferous Rooks Of England and Scotland," Geol. Mag., 1898, p. 506. Introduction. 39 ledge has now been rendered more definite by the recognition of the remarkable similarity which exists in the sequence, and characters of four of the limestones and the intervening sediments in the coast section of Dunbar, Aberlady, and St. Monans.* The names given to the limestones in the Dunbar sequence have been adopted for East Lothian and for the St. Monans section, and the four limestones which have been correlated are the following : — D. f Skateraw Middle Limestone. C. Skateraw Lower Limestone. B. Longcraig Upper Limestone. A. Longcraig Middle Limestone. The vertical section of the St. Monans beds given below is based on that of Mr. Kirkby,J the only important alteration introduced being the recognition of Mr. Kirkby's " No. 53 pseudo-brecciated beds, light-coloured calcareous, and very irregular in structure and containing crinoids " as the nodular encrinital limestone of Aberlady and Dunbar (B. Longcraig Upper Limestone). 28-32. § Sandstone 33. Dark shale with ironstones above and limestone nodules beneath ; crinoids and ostracods common D. 34. Crinoidal Limestone 35. Shale 36. Coaly fireclay 37. Sandstone 38. Shale, grey . . 39. Coal 40. Fireclay 41. 42. Sandstone 43. Fireclay and shale 44. Coal 45. Fireclay 46^8. Sandstone and shale C. 49. Limestone hard with Products giganteus 50. Shale, dark ; a coal has been worked here and stoops are left 51, 52. Sandstone fireclay and shale B. 53. Nodular Dolomitic Encrinital Limestone 54. Dark fireclay 55. Shale and sandstone 56. Coal, hard 57. White fireclay or marl A. 58. White Coral Limestone, largely Lithostrotion 59. Grey shale, with LinguLa, Aviculopecten, Myalina, Sanguino lites, etc. . . Ft. in. 40 — 50 5 — 2 — — 6 7 6 — 6 — 6 3 — 4 — 2 — — 4 2 — 15 9 2 6 2 — 8 — 7 — 2 3 — — 6 6 6 18 — The Calciferous Sandstone series || together with the associated igneous rocks, which in certain districts are in great excess over the sediments, forms a large area stretching from the sea coast at North * " The Limestones of Aberlady, Dunbar, and St. Monans,'' by C. B. Crampton, Trans. Edin. Oeol. Soe.. 1905, vol. viii. p. 374. f For the correlation of the Aberlady and Dunbar shore sections the reader may be referred to the following pages of the Memoir, where these sections are given. The letters A,B,C,D are affixed to the same limestone in each of these sections, and also to those of the St. Monans section given below. t " The Geology of Eastern Fife," Mem. Oeol. Survey, 1902, p. 150. § The figures are those in Mr. Kirkby's section. || The history of this term is referred to in Chapter IV. 40 The Carboniferous Rocks. Berwick (one-inch Sheet 41), past Haddington, to the neighbourhood of Gifford, and thence south-westward, by Fala, to the western margin of one-inch map 33. This area exceeds 100 square miles in extent, but only about half of it is composed of sedimentary rocks. The series forms also a considerable area in the neighbourhood of Thornton- loch, Oldhamstock, and Cockburnspath— all near the eastern margin of one-inch Sheet 33— and smaller areas in the valley of the Dry Burn, near Thurston, and a little south-east of Dunbar. In the detailed account of the Calciferous Sandstone series we shall first describe the area between Dunbar and Ceckburnspath, leaving to the last the North Berwick and Garleton area, where the igneous rocks attain their maximum development. These igneous rocks are in close association with the rocks of sedimentary origin, and the field relations of the two will be discussed together. In the same chapter descriptions of various igneous rocks which occur in other parts of the one-inch Sheet 33 will be introduced, so as to con- centrate all the available information about the volcanic history of the series. The best sections of the sedimentary beds of the series are those on the coast between Dunbar and Cockburnspath, but they are far from complete. In places there are indications that the beds admit of division into the four groups, established in North Northumber- land,* which are indicated below, beginning at the top. Calciferous group with marine limestones. Carbonaceous or Scremerston group. Fell Sandstones. Cementstone group. The Cementstone group is, however, the only one of these divisions which is well developed according to the prevalent Northumberland type. It also clearly resembles the same group near Edinburgh and again at Ballagan, in Stirlingshire ; but it differs considerably from the basal Carboniferous beds of the East of Eife. The occurrence of various beds of oil-shale, partly in the highest of the above four groups, indicates an approach to the conditions which led to the formation of the great Oil-shale group of Mid and West Lothian. The three groups of the Carboniferous Limestone series are shown below in descending order, together with some details regarding their local development. 3. Upper Limestone group, consisting of four thin marine limestones separated by much thicker divisions composed of sandstone, shale, etc. It occurs on the coast near the western edge of the one-inch Sheet 33, and also inland south of Tranent. On the coast the thickness is about 316 ft. 2. Edge Coal group (middle or coal-bearing group), mainly composed of alter- nations of sandstone and shale. It includes many valuable coals which are largely worked, but is not so thick as the same group often is in the Mid-Lothian basin, and contains fewer coals. The average thickness is perhaps 80 fms. It occupies the greater part of the East Lothian coal basin, and is perhaps represented to a very small extent by certain beds on the shore a mile east of Dunbar, and north-east of East Barns. * Hugh Miller, " The Geology of the Country around Otterburu and Elsdon," Geol. Survey Mem., 1887, pp. 4-5. W. Gunn, " The Geology of Belford, Holy Island, and the Faroe Islands, Northumberland," Geol. Survey Mem., 1900. p. 2. Introduction. 41 1. Lower Limestone group, including a considerable proportion of beds of marine limestone, some of which are much thicker than any in the Upper Limestone group. Average thickness of the group perhaps rather more than 300 ft. In one-inch map 33, it forms a broad rim round the east and south sides of the East Lothian coal basin, also an area along the coast between Dunbar and Thorntonloch, and a very small outlier resting on the Calciferous Sandstone series near Lennoxlove, south of Haddington. The total thickness of the whole series may thus be estimated approximately at 1100 ft. The best sections of the Lower Limestone group are those on the coast between Dunbar and Thorntonloch, and the names adopted for the different limestones in this district have therefore been applied, as far as possible, to those in other localities also. In the Carboniferous Limestone series thin coals frequently occur immediately beneath limestones — a phenomenon also observed in other Carboniferous Limestone districts. The following descending order of succession is frequently repeated — Coal, Fireclay and Sandstone, Shale, Limestone, and it seems as if after a set of strata had been completed in the above order by the formation of a coal, either at or very near a land surface, a quick depression had taken place and again let in the clear sea. c. t. c. The Millstone Grit and Coal-measures are confined to a small basin in the neighbourhood of Port Seton and Prestonpans. Upper Carboniferous plants make their first appearance in the higher portion of the Millstone Grit ; the lower portion has proved unfossiliferous in this locality, but in the neighbouring Mid-Lothian basin it has yielded Lower Carboniferous plants such as occur in the underlying Carboniferous Limestone series. These facts are evidence of the marked palseobotanical break which Dr. Kidston has recognised in the Millstone Grit of the Lothians. e. b. b. CHAPTER VI. CALCIFEROUS SANDSTONE SEEIES. DISTEICT BETWEEN DUNBAR AND COCKBURNSPATH.* The rocks now to be described occupy most of an area, about eight square miles in extent, which stretches along the coast in a south- easterly direction for three and a half miles, from Long Craig, near Thorntonloch, to a bay a quarter of a mile east of Cove (Fig. 2). On Fig. 2. — Map of Coast near Cove Harbour. the coast the northern boundary coincides with faults, which bring on the Carboniferous Limestone series ; but these faults are probably not large. Near the south-eastern end the beds dip steeply N.N.E., and the southern boundary is formed by the top of the Upper Old Red Sandstone emerging conformably from below the Carboniferous rocks. Towards the western end, however, near Oldhamstocks, the southern boundary is much confused by faults, and the Upper Old * Certain parts of this district are also described with the North Berwick and Garleton area, in Chapter VIII., so as to complete the volcanic history of the period. Cockburnspath and certain other places mentioned in this chapter are included in one-inch map 34. District between Dunbar and Cockbumspath. 43 Red Sandstone extends northwards, as a sort of wedge within the Calciferous Sandstone series, for more than a mile. The western boundary is defined by the Inner wick fault, with upthrow to the west, which brings up the coarse Lammermuir conglomerates of Old Red Sandstone age. On the north-western side of the Thorntonloch and Cockbumspath area, there are two other much smaller areas also occupied by the Calciferous Sandstone series, situated near the north-east side" of the Innerwick fault ; but these may be connected with one another and with the larger area by narrow drift covered strips. The smaller and more southerly of these two is in the valley of the Dry Burn, where the Calciferous Sandstones emerge naturally from beneath the Carboniferous Limestone series. The other area extends from near Little Pinkerton in a northerly direction, past Broxburn, to the coast a mile east of Dunbar Harbour. The length from north to south is probably more than a mile and a half, but the breadth is never as much as a quarter of a mile. This area is much confused by faults, and most of the beds exposed occur in inverted order, but in the southern part the top beds appear without a discordance on the west side of the Carboniferous Limestone series. The most important section is on the coast near Cove Harbour, not far from the south-eastern end of the Thorntonloch and Cock- bumspath area ; but unfortunately the sequence is interrupted by the Cove fault, with a downthrow to the north, near which the beds become very steep with a nearly parallel strike. The position of this dislocation is seen again inland in Dunglass Burn, but here also the adjacent beds are very steep and strike nearly parallel to the fracture, so that the horizons which are faulted out on the coast do not appear. It is clear from the above section and from others, for instance in Dunglass Burn above the Cove fault, on the coast a mile east of Dunbar Harbour, and in the railway cutting south of Brox- mouth, that the bottom beds of the series have much the same character as those on Tweedside and the Borderland, being chiefly represented by greenish grey or purple clayey shales, thin impure fine-grained and generally unfossiliferous limestones or cementstones, usually of a pale grey, but sometimes of a reddish colour, together with intercalated fine-grained dirty-grey or greenish-grey sandstone. In the Cove section there is evidence of about 500 ft. of beds belonging to this Cementstone group, without reaching the top, but this estimate includes a sandstone, about 140 ft. thick, which is intercalated near the base. In Dunglass Burn the exposures are not so clear, but there may be a greater thickness. In the Broxmouth railway cutting 300 ft. of beds of the Cementstone group are seen in reversed order without reaching the top. On the coast east of Dunbar about the same thickness of beds is seen, again in inverted order and without reaching a natural base, on the west side of two lavas. These beds must originally have underlain the lavas, and intercalated between the lavas and succeeding them we find other strata, including a con- siderable proportion of red clay-shale, so that the thickness observed of the sedimentary portion of the Cementstone group may be 400 ft., while that of the contemporaneous igneous rocks is perhaps 150 ft. In the Cove section the boundary between the Cementstone group 44 Calciferous Sandstone Series. and the underlying Upper Old Red Sandstone is not sharply defined. Different observers might adopt slightly different lines, but the range of variation would probably not exceed seven or eight feet. The section is somewhat as given below, in descending order, but some of the higher beds are only seen in banks above the shore, and their boundaries are not distinct. Ft. in. Clay-shale, and spaces in which we suppose this rook to occur, together with two thin bands of greenish grey fine grained soft sandstone . . . . . . . . • • . . 35 — Purple, purplish red or greenish grey clay-shale, with two thin bands of cementstone near the base . . . . . . 22 — Purplish red and greenish grey shale, with thin courses of soft yellow calcareous sandstone . . . . . . . . . . 52 — Soft greenish grey sandstone . . . . . . . . . . 9 — Shale .. .. .. .. .. •• ..10 — Conglomerate with bits of cementstone, many remains of plants and Spirorbis. Rather like the Eastern Hole bed (near the bottom of this section) . . . . . . . . . . . . 1 — Alternations of clay, shale, and sandstone, about equally divided 28 — Yellow calcareous sandstone . . . . . . . . . . — 8 Shale .. .. .. .. .. .. . . 22 — Calcareous sandstone . . . . . . . . . . . . — 8 Greenish grey clay -shale . . . . . . . . 57 — Soft yellow sandstone . . . . . . . . 23 — Conglomerate with sandy matrix, and lumps of cementstone and carbonaceous material . . . . . . . . . . 1 — Greenish grey shale . . . . . . . . . . . . 5 — Cementstone course . . . . . . . . . . . . — 6 Shale .. .. .. .. .. .. . . 36 — 'Soft flaggy sandstone . . . . . . . . 15 — Soft greenish grey massive fine grained sandstone, with lenticles and big round balls of calcareous sandstone and thin lenticular con- glomerates, from a few inches to a few feet thick, containing pieces of cementstone and shale . . . . . . 75 — Shale courses . . . . . . . . . . . . 3 — Flaggy greenish grey soft sandstone, with thin lenticular conglom- erates containing pieces of cementstone . . . . 27 — Alternating massive and flaggy soft fine grained sandstones, with thin lenticular conglomerates containing pieces of cementstone Q y and plant remains Calcareous band with Sanguinolites abdenensis Eastern Hole conglomerate, with pieces of cementstone, sometimes eight inches long and containing fish scales and fish spines. Remains of plants and tree stems in upper part Purplish red soft shaly sandstone with nodules of cementstone Cementstone with some shale Greenish grey shale with cementstone courses near the middle, one of which contains plant remains Red and white sandstone weathering into knobs Cementstone, deep red at the top Greenish grey and red clay It will be seen that the bed with Sanguinolites abdenensis and the conglomerate with fish and plant remains occur rather more than 50 ft. above the base of the group. In Oldhamstocks Burn a con- glomerate with cementstone pieces occurs, perhaps on the same horizon, but it is only about 20 ft. above the base : it is not well seen, and the parts exposed do not show any fossil remains. In the 23 — 1 6 3 14 — 1 (i 32 2 — 1 6 3 — 504 4 District between Dunbar and Cockburnspatfi . 45 railway cutting near Broxmouth we know of no conglomerate on this or any other horizon. In the coast section a mile east of Dunbar Harbour there is a conglomerate, in places as much as 6 ft. thick, and containing many pieces of cementstone, .but this is only 50 ft. below the lower lava and is probably on a higher horizon than any of the conglomerates seen near Cove. The Horse Roads Sandstone is seen again in Oldhamstocks Burn and in Berwick Burn 500 yds. N.N.W. of Hoprig, in the latter burn in association with a conglomerate containing pieces of cementstone, but it does not appear to be represented in the Broxmouth railway cutting. The calcareous balls, through which the bedding planes can be traced without interruption, project in weathered exposures and are often several feet long. A specimen (10692) * has been ex- amined under the microscope by Dr. Flett, and found to contain rounded bits of quartz, fragments of microcline, orthoclase, iron oxides, muscovite, chlorite, one or two scales of biotite, bits of finely laminated limestone, garnet, epidote, and chert (?). On the coast immediately to the north of the Cove fault, which as already stated has an important downthrow in this direction, we see a thick yellow rather coarse false-bedded sandstone — the Kip Carle Sandstone — containing remains of plants and tree stems and a thin coal smut about 20 ft. above the bottom. The thickness exposed is 50 ft., or perhaps rather more, and we find, dipping steeply above this bed in a N.N.W. direction, an alternating group of pale and dark grey shales and thin yellow sandstones, together with thin coals and ironstone courses, the lowest of which contains remains of Entomostraca. There are at least six coals, but all are poor in quality and the thickest is only nine inches. This Carbonaceous group is about 85 ft. thick, and it seems likely that it corresponds, as first suggested by Mr. Gunn,f to part of the Scremerston or Carbonaceous group which has long been known in North Northumberland. It is uncertain whether the Kip Carle Sandstone forms an intercalation in this Carbonaceous group or whether it is the top of a lower more barren sandstone group, corresponding to the Fell Sandstones of the Border- land. In North Northumberland Mr. Gunn estimates the Scremerston group and the Fell Sandstones group to be each 600 ft. thick, and it seems probable that at Cove a considerable thickness of beds belonging to these groups has been faulted out. We cannot point to any sand- stones inland which can be correlated with confidence with the Fell Sandstones, but near Branxton there are considerable masses of deep red, probably stained, sandstones, which generally dip north-east, and it is possible that the lower of these may be on the horizon of the Fell Sandstones. The coal-bearing beds already spoken of at Cove do not appear to be exposed again inland. Similar beds are seen on a slightly higher horizon on the coast, and also in Dunglass Burn, but they do not promise to be of any economic value. The strata found on the coast between the Kip Carle coal-bearing beds and the foot of Bilsdean are shown below, in descending order — * Numbers in brackets refer to slides in the Geological Survey collection. f " Notes on the Correlation of the Lower Carboniferous Rocks of England and Scotland," Geol. Mag., 1898, p. 342. 10 46 Calciferous Sandstone Series. Ft, Bilsdean Sandstone : yellow rather fine grained evenly bedded . . 40 Purple and greenish grey marls with calcareous sandy seams descend- ing nearly vertically, perhaps along suncracks, from the base ot the overlying bed ... . . • • • • • • Alternations of greenish grey marls and yellow sandstones otten weathering in knobs, and with ferruginous and calcareous streaks and lumps Yellow flaggy sandstone Pale clay-shale with courses of sandstone and ironstone Oil-shale Greenish grey and purple marls with irregular ferruginous lumps . . Cove Harbour Sandstone : yellow or purplish red false-bedded massive rather coarse : abundant lenticles of deep red and buff sandy shale near the base of the upper half Alternations of dark grey shale and yellow sandstone Yellow and purple coarse grained sandstone Sandy shale . . . • ■ • • • • • • • Limestone with crinoids, Productus and abundant Spirifers : Cove Upper Limestone Shale Flaggy unevenly bedded yellow sandstones Coal Fireclay Unevenly bedded yellow sandstone, with fireclay and shale with plant remains Shore Goats Sandstone Sandy shale with many nearly vertical worm tubes Sandstone and shale Calcareous sandstone with crinoids, brachiopods, and lamellibranchs : Cove Lower Limestone Alternations of shale and sandstone Massive white sandstone Shale with abundant remains of Cardiopteris polymorpha Soft yellow sandstone Shale (space for) Heathery Heugh Sandstone: massive false-bedded, yellow, red or purple in colour : rather coarse, some of the quartz grains being as large as peas : rows of iron-shot purplish red lumps, the size of walnuts Purplish red marls and yellow sandstones Massive false-bedded yellow and red sandstone . . Purple and grey marls Yellow and red false-bedded rather coarse sandstones If to this 515 ft. we add the Kip Carle Sandstone and Carbonaceous beds, we get a total of 650 ft. for all the beds observed between Bils- dean and the Cove fault. The Cove Upper Limestone is about 210 ft. below the top of the Bilsdean Sandstone. We are unable to estimate the thickness between this bed and the base of the Carboniferous Limestone series of the district (see page 50), but it probably amounts to at least several hundred feet more. It seems probable that the Cove Lower Limestone, which outcrops a little south of the bend in the south wall of the harbour, and the Cove Upper Limestone, passing close at the south side of the harbour mouth, correspond respectively to the Dun and Woodend Limestones of Northumberland.* The * Mr. W. Gunn, Qeol. Mag., 1898, p. 347, considered the Cove Upper Limestone to represent the Woodend and the Dun group. He probably had not noticed the Cove Lower Limestone. In Northumberland the base of the Dun Limestone was taken as the upper limit of the Scremerston Coal group. 20 — 10 — 6 — 1 — 20 — 85 14 — 7 — 6 — 1 6 13 — 7 — — 3 1 — 19 8 — 2 — 14 — 15 22 — 8 — 9 — 7 — 22 " 92 14 — 18 — 5 — 30 — 515 9 District between Dunbar and Cockburnspath. 47 overlying Cove Harbour Sandstone may be matched with a thick sandstone which overlies the Woodend Limestone at Spital, but the beds between the two limestones at Cove are in thin alternations, amounting in all to about 64 ft., whereas near Spital the interval between the Dun and the Woodend is almost entirely composed of a massive sandstone. In Dunglass Burn, about half a mile south-west of the Mansion House, there is an impure calcareous horizon, about 9 ft. thick, which includes at least three bands- with remains of lamellibranchs, but, as far as observed, no crinoids. It is possible that it represents the Cove Upper Limestone, and there is a thick sandstone, about 70 ft. above, which resembles the Cove Harbour Sandstone. Below this calcareous horizon comes 25 ft. of flaggy sandstone and shale, and then a coal, about 9 in, thick, which has been dug at the outcrop. Mr. Gunn correlated the Cove oil-shale with an oil-shale which is very constantly found between the Oxford and the Woodend Lime- stones in North Northumberland.* On the shore north of the harbour it makes a conspicuous outcrop and can be traced east and west nearly a third of a mile, dipping north at 10° or 15°, but a little further north the beds flatten and occasionally dip east, and about 170 yds. south-east of the foot of Dunglass Burn the oil-shale, and the peculiar purplish red marls which underlie it, emerge again. From this locality the shale can be traced north-east for 400 or 500 yds., but beyond this point it has not been observed. Many striking instances of false-bedding are seen in this locality, and it is suggested that it may have been denuded away in certain areas before the higher beds were deposited. At the foot of Bilsdean the beds are nearly horizontal, and the base of the Bilsdean Sandstone is exposed in the cliff with underlying grey and purple marls and ironstone courses. Below these marls lies a false-bedded rather coarse reddish sandstone which forms the isolated sea-worn pillar of Standalane, f on the foreshore about a third of a mile north-west of Bilsdean foot. The Standalane Sandstone closely resembles the Cove Harbour Sandstone, but on the shore eastwards it seems to come on above the oil-shale position. On the north-west side of Standalane the dip is east or north-east, and we should expect to find the oil-shale below the sandstone, but, instead of this, we observe a set of greenish grey and occasionally purplish marls, sandstones, and impure ironstone courses, which somewhat recall the appearance of certain beds in the Cementstone group, and also in the Oil-shale group of Mid-Lothian. These marly beds are extremely false-bedded, and are affected by various lines of move- ment, some of which keep to the bedding planes, but none of these movements appear to be great, and there seems no room for any powerful fault which can have introduced on the west a group of beds which in the original sequence occupied a higher position than the Cove Harbour and Standalane Sandstones. * Geol. Mag., 1898, p. 347. t Since this description was written Standalane has fallen, having succumbed to the storms in the spring of 1906. A sketch by Sir A. Geikie was reproduced in the " Geology of East Lothian," Mem. Geol. Survey, 1866, p. 29. The fossil tree stump noticed in Bilsdean creek at the time of the original survey was not seen during the re-survey (op. cit. p. 28). 48 Calciferous Sandstone Series. At the base of the cliff a few yards west of Standalane an irregularly bedded clayey shale yields beautifully preserved fossil ferns, Telangium affme [Sphenopteris Auctt.], in great abundance. About 200 yds. west of Standalane a bright coal, ten inches thick, emerges from beneath the marly beds, and a little below this horizon, just south of the old salt-pans, is a bed of shaly sandstone crowded with worm pipes, which are not quite vertical but appear to have been pushed forward from the south. This piped bed closely resembles a similar band which comes between the two Cove Limestones, but it is difficult to see how it can be on the same horizon. The beds below this position continue to dip easterly, and, as we go west, a thick massive sandstone, which has been quarried, is first met with, followed by the Linkhead Limestone, which is perhaps six or seven feet thick, but is impure and shaly and represented in part by large nodules embedded in shale. It does not resemble either of the Cove Limestones, and is especially characterised by the abundance of IAtho- strotion junceum, crinoids and spines of Archwocidaris. Some thin seams of shale interstratified with the top of the limestone near high water-mark contain small crystals of selenite between the weathered layers. Interleaved in the sandstone which overlies the limestone are some thin bands of dark shale which are full of fossil plants, among which are the following : — Telangium affine (L. and H.). Sphenopteris mackaneckii (Ett.). S. subgeniculata (Stur.). Bhodea patentissima (Ett.). Asterocalamites scrobiculatus (ScMoih. ). Sphenophyllum tenerrimum (Ett.). This Linkhead Limestone was supposed by Mr. Gunn to be the Oxford Limestone,* which in North Northumberland is 300 or 400 ft. above the Woodend Limestone, but, unless there is some big fault on the west side of Standalane — a supposition which, as already indicated, we cannot willingly accept — the Linkhead Limestone ought to be on the horizon of the Cove Upper Limestone, that is to say, of the Woodend Limestone. The marly beds which come above the coal, just spoken of, closely resemble some which are seen in the bay of the Burgess Cove, on the north side of Sharper Head, north of Berwick, where they are brought against the Oxford Limestone, by a fault which is considered by Mr. Gunn to have a throw of about 300 ft. down to the south-east, bringing these marls on the north side against the limestone on the south.f These marly beds in the bay must in the original sequence, therefore, be below the Oxford Limestone, and their resemblance to the beds west of Standalane strengthens the supposition that the Linkhead Limestone corresponds to the Woodend Limestone. The Linkhead Limestone makes an outcrop 130 yds. broad, and on the north-east side is bounded by a fault, inclining north-east, which brings on a false-bedded massive sandstone, probably the bed which overlies the limestone on the east side. The sandstone * Geol. Mag., 1898, p. 347. f " Notes on the Rocks about Berwick-on-Tweed," Proa. Ber. Nat. Field Club, vol. xvi. p. 313. District between Dunbar and Cockburnspath. 49 north-east of the fault is only exposed for a short distance, beyond which there is an obscure tract, covered for the most part with sand and gravel, which extends more than half a mile along the shore to Thorntonloch. The ten-inch coal which occurs above the Linkhead Limestone is said to have been formerly worked on a small scale at the outcrop near the top of the cliff at the salt-pans. The coal appears to improve in thickness inland, for near the salt-pans two old levels have been driven in a south-west direction, and in the fields a considerable distance from the coast, and on the south-west side of the railway, there are indications of old shafts which were probably connected with these levels. The old workings are said to have ceased about 100 years ago. Recent borings in this locality, the results of which have been kindly communicated by Mr. James Cleland, have proved a. coal — 17, 18, and 20 ins. thick in the several bores — to be lying at a shallow depth, within 13 fms. of the ground surface. In Dunglass Burn for nearly a mile above the foot the beds are nearly flat. The Bilsdean Sandstone forms the tops of the banks and is underlain by a thick sandstone of redder colour which seems to correspond to the Cove Harbour Sandstone ; but in some parts of the Dean the two sandstones come together. About 540 yds. above the mansion-house the dip is rather steep down stream, and lower beds, extending down below the Dunglass calcareous horizon, are exposed, but no oil-shale is seen, and it seems hardly possible that the Cove oil-shale can exist here. On the shore between Thorntonloch and the base of the Carboni- ferous Limestone series the strata undulate at low angles. Near the bottom of these beds a pale grey clay, mixed with calcareous lumps and thin courses of sandstone and ironstone, is overlaid by a soft false- bedded yellow sandstone, with occasional plant remains, which is faulted on the north against the basal beds of the Carboniferous Limestone series, and hence its thickness cannot be determined. It seems probable, however, that the faults referred to are not large, and that the sandstone on the south is on the horizon of the thick sandstone which, with certain shaly partings, forms the top of the Calciferous Sandstone series in the railway cutting near Broxmouth. The section of the sandstone in the cutting is represented below, beginning at the top. Ft. in. Flaggy unevenly bedded reddish purple sandstone with some purple shale . . . . . . . . . . . . 16 — Ferruginous bed with abundant remains of Nucidana attenuate/, and other fossil lamellibranchs . . . . . . . . 3 Flaggy reddish purple sandstone Massive purplish red and white rather coarse false-bedded sandstone Purple white and buff clay shale Massive purplish red and white rather coarse false-bedded sandstone A volcanic ash which appears on the west side of these beds probably belongs to a much lower horizon, being separated from them by a powerful fault with a downthrow to the east. A poor exposure of the beds immediately below the Carboniferous 4 11 — 42 — 8 — 70 — 147 3 SO Cahiferous Sandstone Series. Limestone series in Dry Burn consists chiefly of red and yellow false- bedded sandstones— no doubt the same beds as those shown in the railway cutting. Owing to the drift cover inland and the long stretch of sandy shore south of Thorntonloch, the succession of strata between the Bilsdean Sandstone — the highest bed we know on the coast south of Thorntonloch— and the base of the sandstone referred to in the railway cutting, is by no means clear. If the Linkhead Limestone corresponds to the Cove Upper Limestone and the Woodend Lime- stone of Northumberland, as we suppose, and if the strata have not greatly thinned between Berwick and Thorntonloch, we ought to have, between this limestone and the base of the Carboniferous Lime- stone series, more than 600 ft. of beds, and another limestone — the Oxford Limestone — near the middle of these beds. A boring recently made at Catcraig * has pierced 365 ft. of strata below the base of the Carboniferous Limestone series, but without meeting any lower limestone or any coal of value. Nearly the whole of the 365 ft. consists of sandstone which is to a large extent of a reddish colour. At the base of the Longcraig Lower Limestone a fireclay, 5 ft. 1 in. thick, was found with an inch of coal a little above its base ; at 60 ft. below the limestone base, a two-inch coal was pierced : at 132 ft. below, a four-inch coaly blaes : at 169 ft. below, a three-inch coal with a roof composed of about three feet of dark blaes with ironstone ribs and a floor of fireclay. In the part of Thornton Burn below the railway there is only one small rock exposure. Westwards beyond the railway near Thornton Mill, some dark grey shales, of considerable thickness, appear, together with flaggy sandstones and thin ironstone courses, lying at gentle angles. Further west, and apparently above these beds, we find, near Crowhill, a two-inch coal and some fireclay, and a thick coarse red sandstone, which seems to cut across the denuded edges of a series of purple grey clays, red and white sandstones and ironstone courses. Just below Innerwick Castle the lower beds are almost vertical, while in an adjoining area the overlying sandstone dips at an angle of not more than 18°. There are also marked local unconformities within the lower series, and it is difficult to com- prehend the physical structure. It seems necessary to suppose that somewhat violent earth-movements must have taken place, which tilted certain beds into an almost vertical position before the over- lying strata were deposited. A little beyond Innerwick Castle the beds dip more regularly in an eastern direction, and coming above a thick series of red and yellow sandstones we find grey clays and blue shales and a thin calcareous sandstone, which is exposed 50 yds. below Thornton farm. Higher still, on the west side of the river near the farm, a fireclay is exposed, with a ten-inch coal above, fol- lowed by a yellow sandstone. It seems possible that the calcareous band is on the horizon of the Dunglass bed and the Cove Upper Lime- stone, but it has no particular resemblance to either. If the thick red sandstones of Innerwick Castle lie above the Crowhill coal, as they seem to do, then a considerable thickness of beds must occur in the gap between this coal and the base of the * The results of which have been communicated to us by Messrs. Loudon & Meek, of Coatbridge. Dunbar to Traprain Law. 51 Carboniferous Limestone series on the north, unless there is a fault, with a considerable downthrow to the north within this space. One of the faults near the base of the Carboniferous Limestone series on the coast at Long Craig may possibly be prolonged and pass through this space, but in the map it has not been drawn so far. c. t. c. The Country between Dunbar and Traprain Law. In this district the only representatives of the Calciferous Sand- stone series are the Cementstone group, and the volcanic rocks to be described subsequently (Chaps. VII .-X.). The best exposure is the shore section west of Dunbar (Fig. 4, Chap. IX.), where the beds he on the south-east side of the anticlinal axis which passes out to sea in Belhaven Bay. The beds dip at gentle angles to the south- east, and are between 250 and 300 ft. thick, but neither top nor base is seen. They are rather more sandy than the contemporaneous Ballagan Beds of the West of Scotland, but they preserve the char- acteristic alternation of thin beds. A rhythmic succession — sand- stone, shale, cementstone, shale, sandstone — is more common than the cyclic order, sandstone, shale, cementstone. They are divisible into 3 groups, as follows : — 3. An upper group of reddened cementstones, shales and thin sandstones. 2. A yellowish, false-bedded, micaceous sandstone, 45 to 50 ft. thick. 1 . A lower series of green and purple shales, cementstones and thin sandy beds. The sarjdstone (2) lies about the middle of the series. It contains lenticular pebble- and breccia-beds, particularly at its base, which marks a line of contemporaneous local erosion. Other planes of local erosion occur in the lower group, and will be referred to in the description of the volcanic rocks (Chap. IX.). About 250 yds. south of Belhaven Point the sandstone is cut off by a fault, which is seen in the cliff, and passes close to the Spa Well on the shore. In a shab above the sandstone, and below a cementstone band full of Spirorbis helicteres Salter, occur Estheria peachi Jones, and plant remains identi- fied by Dr. R. Kidston, F.R.S., as Samaropsis bicaudata Kidston, and Alcicornopteris convoluta Kidston. From a band of grey shale a little higher up in the section, Dr. Kidston identified Lepidostrobus sp., Lepidodendron veltheimi Sternb., and Stigmaria ficoides Brongt. One of the cementstone bands has yielded Tealliocaris woodwardi (R. Etheridge, jun.). In common with other rocks in this neighbourhood, the sandstones and shales are more or less stained by iron-oxides, but they are less affected than the cementstones, which are changed from a pale greenish or bluish grey to a deep red colour. Only the lowest beds exposed, viz. those cropping out on the south side of the dolerite dyke at the Targets, remain unaltered. One of the higher bands shows that the staining has been produced by the ferriferous solutions percolating downwards from above. The topmost inch of the bed is reddened, and the stain ends off beneath along an irregular line with tongues following down the joints and cracks. This bears out Goodchild's contention that the staining came from above, and it may have been, as he suggested, from a former cover of New Red Sandstone. 52 Calciferous Sandstone Series. One of the normally coloured beds (No. 14) and one of the lowest of the reddened beds (No. 15) have been analysed by Mr. J. S. G. Wilson with the following results : — Si0 2 A1 2 3 Fe 2 8 MnO CaO MgO CO, H 2 6 above 100°C No. 14. No. 15 . . 1533 17-17 6-33 3-43 . . 2-82 3-81 1-56 4-43 . . 24-04 20-74 . . 1410 14-92 . . 34-83 34-43 1-22 1-61 100-23 100-54 No. 14. Pale grey limestone from east side of Belhaven Bay, near Dunbar, and a short distance south of old targets. No. 15. Deep red limestone from east side of Belhaven Bay and a few yards south of No. 14. The nearly constant ratio of (CaO+MgO) to carbon dioxide and the small increase in the amount of iron shows that there is no appreci- able replacement of lime by iron, and that the iron oxide in the reddened bands must be present simply as a stain. The big ash neck west of Dunbar cuts off the top of the series, but small patches of the Calciferous Sandstones occur to the east of it, though they are too small to show on the one-inch map. In the small bay on the eastern margin of the neck a passage from the Upper Old Red Cornstone group into the Cementstone group is exposed. The section is as follows : — Ft. Sandstone with flakes of green shale, more than . . . . . . 6 Green shale and sandy shale with flakes of green shale . . . . . . 3 Greenish micaceous sandstone with nodules of ferruginous breccia at the top, containing fish remains . . . . . . . . . . . . 3 Greenish grey shale . . . . . . . . . . . . . . 1 Sandstone with iron-stained breccia at the top containing Myalina, Spirorbis. Ostracoda, ctenodont rib, Oyracanthus, rhizodont teeth and scales, and Strepsodus portlocki Agassiz * . . . . . . . . . . 2 Gap at base of cliff. ? Shale . . . . . . . . . . 5 Pine, speckled, micaceous sandstone, false-bedded and containing stained concretions. Irregular plant-bed 3 to 4 ft. from base . . 17 Shale .. .. .. .. .. .. .. ..3 Fine, yellowish sandstone with impure cementstone band and small patches of conglomerate . . . . . . . . . . 2 Sandy shale . . . . . . . . . . . . . . 2 Bed sandstone with uneven top, passing down into white, false-bedded sandstone with green clay galls . . . . . . . . . . 6 Reddish micaceous shale with a band of stained cementstone, 1 ft. 3 in. thick 6 Red shale . . . . . . . . . . . . . . . . 3 Pinkish sandstone with oornstones, carious weathering . . . . 6 Reddish, micaceous shales with stained cornstones . . . . 1£ Reddish to grey sandstone with cornstones (stained red), carious weathering, more than . . . . . . . . . . . . . . 45 The Upper Old Red Sandstones with cornstones are seen on the shore below high tide-mark immediately east of the red tuff, and the * The fish remains were identified by Dr. R. H. Traquair, F.R.S. Area South and West of Haddington. 53 section in the overlying beds is traced in the above section in a south- easterly direction into the cliff. Since the cornstones end with the bed third from the base, and the cementstone bands appear at once, the line between Upper Old Red Sandstone and Carboniferous is drawn at this point. Another patch of the Cementstone group is preserved on the south- east side of the entrance to the Broad Haven, faulted down between Old Red Sandstone and an ash-neck. Inland the same group is exposed in the Biel Water from the railway viaduct upwards. h. b. m. Highly micaceous sandstones and grey clay-shales, with occasional cementstone nodules, are exposed at several points in the vicinity of Traprain Law, especially in the field and old quarries to the north of the hill. They undoubtedly belong to the Cementstone group, and have been tilted at high angles by the intrusion of the laccolitic mass of the Law (Chap. IX.). Area South and West of Haddington. This district is naturally divided into two parts by the Dunbar - Gifford fault, which crosses it in a north-east and south-west direction, running parallel with the Lammermuir fault right across the map. The evidence upon which this fault has been drawn may be briefly stated as follows : From Dunbar almost to Gifford it was recognised by Mr. Howell, and a glance at the map shows that along this portion of its course it serves to separate a belt of Old Red Sandstone to the south from an area occupied by Carboniferous rocks to the north. The continuation of the fault in a south-westerly direction to the Gifford Water is marked by an extension of the outcrop of the Garleton Hill volcanic rocks further to the west on its upthrow than on its downthrow side ; while, just where it might be expected to cross the banks of the stream, a well-marked discordance is exposed. Further south-west there is no chance of seeing the fault for four or five miles, but in Birns Water about half a mile south-west of Woodhead, the presence of the fault is probably indicated by high dips of 35° and 60° and by the juxtaposition of rocks of Upper Old Red Sandstone type, containing cornstone concretions, with others of Carboniferous type, containing cyprid limestones and thin coal seams. Again, in the Humbie Water, the outcrop of the same cornstone-bearing group is terminated to the north against an obvious fault ; and further west at Costerton Cottage, where a small exposure shows similar cornstone-bearing marls and sandstones, a fault also seems necessary, since there can scarcely be room for the whole Calciferous Sandstone series between this point and the outcrop of the base of the Carboni- ferous Limestone series. An exactly similar line of argument shows the probability of some fault between the Satighland igneous rock and the limestones of Crichton Dean. It is doubtful whether this rock is a lava or an intrusion, but there can be no question that it is of the type of the lower lavas of the Garleton Hill volcanic horizon, and that, lava or intrusion, it is unlikely to be associated with beds greatly above the Cementstone group. The fault has therefore been continued on the map slightly north of this exposure. From the large area occupied by the Upper Old Red Sandstone 54 Calciferous Sandstone Series. on the south side of this fault it might be expected that all the Carboni- ferous rocks occurring on this side would belong to the lower part of the Calciferous Sandstone series. The mass of limestone, formerly mapped as an " outlier " at Kidlaw, midway between Fala and GifEord, probably does not belie this expectation, for it is now regarded as an ice-transported mass.* There is, however, little known of the Carboniferous strata which lie south-east of the Dunbar-GifEord fault, for all the best sections throughout this area occur in strata which have been assigned to the Upper Old Red Sandstone series. We may mention, nevertheless, that in the Gifford Water a massive white and red sandstone overlies the basement ash of the Garleton Hill volcanic group ; and to the west of this, in the Newhall Burn, there is an exposure of dark shales and thin coals, only a few inches thick, which doubtless overlie the GifEord Sandstone and are perhaps in the position of some of the Scre- merston coals of Northumberland. A coal probably belonging to the same group was also formerly exposed and actually wrought, in the east bank of the Fala Dam Burn, lying upon the south-west side of the anticline which brings up the Old Red Sandstone of the Humbie district. It is said to be about 18 ins. thick and to be underlain by " fireclay." f We may now pass to the portion of the area which is situated north of the Dunbar-GifEord fault. Here, again, the available sections are not sufficient to allow us to make out the stratigraphical succes- sion which prevails in the rocks overlying the Garleton Hill Volcanic group. Our most precise knowledge is based upon a record of a diamond bore which was put down in the old quarry in the limestone outlier near Lennoxlove, south of Haddington. From the bore journal the following section has been con- structed : — Ft. in. Limestone Fossiliferous shales . 9 6 Micaceous shales and sandstones . 11 6 Reddish sandstone 1 Dark fakes with plant remains 6 Reddish and yellow sandstone with soft partings . .' 37 6 Variegated marls with fakes and kingle bands . 139 3 Dark fakes with ribs and balls . . . 13 11 Sandstone . 62 4 a. Hard faky fireclay with plant remains . . 6 6 Hard faky sandstone . 14 9 Dark fakes . . 2 6 6. Inferior oil-shale with balls 2 2 Dark fakes and sandstone 2 6 Dark shale and ironstone ribs 7 ] Mussel-band 7 Oil-shale, inferior 4 Sandstone and faky plies . 11 4 Carry foi ward . 323 3 * P. F. Kendall and E. B. Bailey, " The Glaciation of East Lothian south of the Garleton Hills," Trans. Boy. Edin., 1908, vol. xlvi. p. 6. t In the Summary of Progress for 1903, it is stated that all the coal pieces in this locality have been glacially transported. Re-examination has shown that this is- probably not the case. Area South and West of Haddington. 55 Ft. in. Brought forward . 323 3 Bluish grey limy sandstone . 10 10 Dark faky sandstone . — ■ 5 Dark limy sandstone . 2 9 Dark faky sandstone all with — 6 Dark faky sandstone with balls . . - marine . 10 7 Very sandy limestone fossils. . — 7 Hard sandstone 1 9 Limestone . . 1 — -Lirny sandstone . — 5 Inferior coal 1 10 Faky fireclay . . — 6 Faky marl . . 16 9 Dark fakes and sandstone partings . — 9 Limy sandstone .. 3 4 Faky blaes and hard ribs . . 15 6 Faky blaes with cement balls . . 1 9 392 Proceeding downwards through this section we may note the surface exposures which have been recognised of some of the groups recorded in it. In the first place, the sandstone underlying the Lennoxlove Limestone has been wrought in a rather large quarry, for building purposes, situated upon the side of the hill capped by the limestone. Then, again, there can be little doubt that the marls exposed in the stream banks near Coalstoun, south of Lennoxlove, are portions of the mass proved in the bore beneath this sandstone. The big sandstone underlying these marls is probably the bed which has been quarried at Woodend and Rentonhall and extends north- ward to Bearford, all three places lying east of Lennoxlove. In the Woodend and Rentonhall district this sandstone is underlain by an impure coal, about two feet thick, which was formerly wrought in shallow pits ; this is probably the same coal as was once wrought near Letham, west of Haddington, and its position in the bore may be marked either by the "hard faky fireclay with plant remains" (bed a.) or the "inferior oil-shale with balls" (bed b.). For the " mussel-band " of the bore journal we can give three localities, viz., the bank of the Tyne opposite the distillery, between Haddington and Lennoxlove ; further down the course of the same river close to the outcrop of the trachytic tuff near Stevenson House ; and lastly, the head of a small burn between Sandersdean and Rentonhall, E.S.E. from Lennoxlove. The band is easily recognisable although the lamellibranch whose abundance is its chief characteristic has never been found in a sufficiently perfect state of preservation for accurate determination. In the bore it will be noticed that a curious fossiliferous sand- stone (c.) underlies the mussel-band. The general character of the sandstone would hardly encourage a searcher for marine fossils since much of it is micaceous or faky and contains abundant planty layers. Throughout it, however, casts of various shells and encrinites can be recognised and these increase in importance in certain portions which pass into sandy limestones. A somewhat similar sandstone with marine fossils was found by Mr. Macconochie in the same small burn between Sandersdean and Rentonhall in which the mussel- 1 — — 6 56 Calciferous Sandstone Series. band is exposed. The section is not continuous : if there be no fault between the two exposures the mussel-band must pass under the fossiliferous sandstone, but small faults are common in the district, and judging from the sequence in the bore it seems likely that the mussel-band really overlies the sandstone referred to. E. b. b. Another exposure of the same horizon probably occurs in a small dean, lying between the two branches of the railway east of Long- niddry, where the following section is exposed, partly along the course of the stream and partly in an adjoining quarry. Ft. in. Ochreous micaceous sandstone with marine fossils . . . . 6 Dark shale and ironstone balls . . . . • • ! Bed sandy limestone (encrinital) from 4 in. to Rooty fireclay Sandstone with limy, planty and micaceous layers (bottom not seen) 10 — Fireclay, with two thin coal seams . . . . . . . . 3 — Calcareous fireclay and ironstone (very hard) . . . . . . 2 — Sandstones . . . . . . • . . . • • • • — — A thin encrinital limestone, which is seen a little to the north in the burn near Ballencrieff Mains, is also considered to occupy the same position. G. B., c. b. c. We may now notice a marine encrinital limestone which we shall name the Sandersdean Limestone, from the locality where it is typically developed, south-east of Haddington. Mr. Macconochie has noted the occurrence in it of certain lamellibranchs of which Naiadites crassa (Flem.) is the most important, and has thus been able to identify its outcrops in Letham Burn, west of Haddington, in Sandersdean Burn, south-east of Haddington, in Newhall Burn, east of Grifford, and in the Humbie and Birns Water, south-west of East Salton. In the Sandersdean Burn the Sandersdean Limestone outcrops in proximity to a planty limestone with Platyostomella scotoburdiga- lensis (R. Bth., jun.), with two inches of oil-shale above and six inches of coal below. There are obvious signs of faulting in the intervening exposures, but in Letham Burn, west of Haddington, the Sandersdean Limestone is again in close proximity to, and dipping towards, the out- crop of a planty limestone with Platyostomella, surmounted by a dark shale with ironstone nodules. It seems probable, therefore, that the Sandersdean Limestone lies not many feet beneath the Platyostomella bed. Furthermore, at the head of the small burn lying immediately to the east of Sandersdean, the Platyostomella bed is separated from an outcrop of the " mussel-band " by a few feet of strata under which it dips, and it seems certain that the " mussel-band " overlies the Platyostomella bed. In the Lennoxlove bore no sign of the Platyosto- mella bed was found, but the " mussel-band " was underlain by the fossiliferous (marine) calcareous sandstone, already described, which therefore probably represents the Sandersdean Limestone. In Sandersdean, the limestone overlies dark fireclay with four thin coal seams and a dark band of planty ironstone which rests in turn upon a mass of grey fireclay. Of the still lower beds we know little. Some of them are poorly exposed in the Humbie Water, where, at some distance below the Sandersdean Limestone, thin cyprid limestones are seen, in the course of the stream, which may represent the Burdiehouse position. As to the chance of getting workable oil-shale in East Lothian Area South and West of Haddington. 57 we have little evidence. The Lennoxlove bore did not reach deep enough to settle the question, and it is doubtful whether any other trial has yet been made which might reasonably be expected to do so. Should further trial be undertaken it would be best to begin boring on the outcrop of the mussel-band near Sandersdean. The position of the Sandersdean Limestone would thus be ascertained, and, if, further down, operations were interrupted by coming upon the volcanic rocks at no great distance from the surface, boring could be recommended from the outcrop of the Sandersdean Limestone either in the Newhall Burn or the Humbie Water, thus always starting from a known horizon. It need scarcely be said that there is very little prospect of anything of value being found south of the Dunbar - Gifiord fault. e. b. b. CHAPTER VII, CALCIFBEOUS SANDSTONE SERIES.— (Continued) The North Berwick and Garleton Area.* The group of rocks now to be described occupies the whole of the cliffs and foreshore from the mouth of the Tyne to Aberlady, a distance of 16 miles, and as we proceed from east to west the succession is on the whole an ascending one. There are, however, numerous local exceptions to this rule, owing to the fact that the rocks have in many places been folded and squeezed into a series of elongated domes and basins, which are indicated on the foreshore by the frequent horseshoe form assumed by the miniature escarpments. The in- clination of the strata in these minor folds is often steep near to the margin of any particular dome or basin, so that there is a tendency for rapid changes of dip ; thus in inland exposures, which are almost invariably much obscured by drift, it is frequently impossible to be certain of the relationships existing between two neighbouring exposures. In this area the rocks below the Lower Limestone group fall naturally into three main divisions as shown below in descending order. III. The rooks above the volcanic sheets. 11. The volcanic sheets, and pyroclastic rocks, etc., between them. I. The rocks below the volcanic sheets, all of which appear to belong to the Cementstone group. The bands of impure limestone or cementstone which are the chief characteristic of this group elsewhere, are not, however, well developed anywhere in this area. I. THE ROCKS BELOW THE VOLCANIC SHEETS. The rocks that underlie the volcanic sheets are well exposed "I" on the coast in the neighbourhood of North Berwick, and eastwards to Tyne Mouth. They are of peculiar interest not only from their com- position, but also on account of the light they throw on the physical conditions of the area at the time of their formation. Sir A. Geikie % long ago pointed out that these rocks were probably formed in a sinking area to which the sea rarely had access, and recent researches in other lands have helped to explain their mode of origin. They vary in composition from normal clastic material to purely pyro- clastic, and between these two extremes there is every gradation. Moreover, it is a special feature of all these varieties that they locally * North Berwick and many other localities mentioned in this chapter, which are included in one-inch map 41, are shown in the sketch-map, Fig. 3, on opposite page. ■j- A detailed description of this coast section has been given by Sir A. Geikie in the " Geology of East Lothian," Hem.. Qeol. Survey, 186(i, p. 32. { " The Carboniferous Volcanic Rocks of the Basin of the Forth," Trans. Roy. 8oc. Edin., 1879, vol. xxix. p. 444. 68 North Berwick and Garleton Area. ■E--S 2 © rs K 4> « la i s o 4= m o •a -b * 3 3J3 o . ■t;o p* > a © -111" s . -» Pi r o 6» a - > OJ3 CO 5 c 5! p c *- §S_.t a 3 f, 0< abov pe. tc. Crai 1 - ^. o ^r CO es, etc arkle < tones, Basal SS-€d Sandsl avas, Is, san ite. x ..*SS< =- «S S 50 «?f w .B H3 © *«■§* 60 , Calciferous Sandstone Series. contain large rock fragments set in a matrix of unusually fine texture. Commencing with the normal sedimentary material, a perfect illustration of this curious phenomenon occurs on the scars about two miles north of Tyne Mouth, where much of the rock consists of fine soft marl, enclosing a large number of blocks of almost identical material, some of which are more than two feet long and a foot thick. These large blocks cannot have been much buffeted about and their oc- currence in such a fine matrix is at first difficult to account for. The formation of such deposits has, however, been described by various observers,* who show it to be due to desert conditions, when sudden though rare floods give rise to deluges of fine mud which have an exceptional capacity for transporting large blocks without doing them any great injury. In the case of the pyroclastic material even more conclusive evidence of this mode of transport has been met with, the details of which are given later on. For convenience of description the rocks below the group of lavas may be subdivided as follows, in descending order : — d. Marls, sandstones, etc., with some pyroclastic material. c. A more or less continuous limestone horizon. 6. A great mass of green ash. a. Red marls and sandstones which pass insensibly into the overlying mass of ash. We shall now describe the character and coastal distribution of these subdivisions in detail, beginning with the lowest. a. The lower portion of the red marl and sandstone group is exposed on the shore a little north of Tyne Mouth and consist of thin beds of soft white sandstone associated with a considerable thickness of red marls, some of which are rather hard and sandy while others are much softer and often of a lighter hue ; with the latter a few thin bands of cementstone also occur. These rocks have usually a low dip to the north-west, and give rise to a series of slightly curving sandstone scars where they crop out on the foreshore. They have yielded the following fossils to Mr. Macconochie : — Alcicornopteris convoluta Kidst. Telangium affine (L. and H.) [Sphenopteris Avctt."]. Lepidodendron veltheimi Sternb. Lepidostrobus sp., very abundant. Samaropsis bicaudata Kidston. Spirorbis pusillus (Mart.). Entomostraca. Pseudogalathea sp. Modiola Macadami Portl. Rhizodont scales. In the above sandstones and marls igneous material is rare, but as the great stock of St. Baldred's Cradle is approached higher beds are rapidly brought on by the increasing dip, and, in these, rounded * These phenomena have been specially dealt with in recent years by American Geologists, and W. M. Davis, " The Geographical Cycle in an Arid Climate," Journ. of Oml., 1905, vol. xiii. p. 38], gives a list of works bearing on the subject. One of the most interesting is by W. J. M'Gee, on " Sheetfiood Erosion," Bull. Oeol. Soc. America, 1897, vol. viii. pp. 87-112. See also " Charnwood Forest, a Buried Triassic Landscape," Prof. W. W. Watts, Oeocjr. Journ., 1903, vol. xxi. pp. 62, 63. North Berwick and Garleton Area. 61 and subangular fragments of lavas are common, though the matrix still continues to be sandy marl with little if any admixture of fine ash. The beds are dragged down on all sides towards the stock referred to, so that the same rocks which form the scars of Tyne- mouth are found again on the north-west side of the stock and have yielded Entomostraca and Telangium. After passing the loose sands which cover the foreshore for nearly a mile north-west of St. Baldred's Cradle a continuous series of scars is exposed at low tide for a great distance to the north-west. Opposite Scoughall these scars often assume a horseshoe form due to the dome and basin structure already referred to. The dominant rock here is a curious lumpy-weathering red marl, varying in hardness and tint, and containing a great number of included fragments of similar marl and of soft marly sandstone, some of which are more than two feet long. Igneous fragments apparently allied to the overlying basic lavas are present in considerable numbers along special bands, but elsewhere are rare. Like the marl blocks, however, they seldom show any noticeable amount of rounding by attrition. In some cases where the marl blocks are unusually abundant the whole rock has a considerable resemblance to an agglomerate and weathers into rounded lumps or hummocks. It is this type of rock which affords such clear evidence of desert conditions, for the rains of desert regions, though rare, are violent while they last, and give rise to tumultuous rushes of mud-charged water (" Sheetfloods ") which possess extra- ordinary transporting power, combined with a very reduced tendency to produce attrition of the large blocks that are swept along with them. The first dome opposite Scoughall is separated from the basin to the north-west by a narrow belt of ground formed of harder sand- stone, the individual beds of which give rise to small scars striking seaward. The details of the structure are difficult to make out, but it seems clear that many local wrenches have taken place, though it is not easy to locate any one definite fault. A little further to the north-west, and at a slightly higher horizon, a peculiar hard white sandstone, markedly false-bedded, can be traced on the foreshore for a considerable distance ; its outcrop is shown on the map, as it serves the double purpose of bringing out the structure of the ground and of illustrating the rapid variation of the beds which underlie it. Like many similar bands in both the marly and ashy beds it probably marks the infilling of a local hollow of erosion. A little west of the termination of its outcrop the foreshore is crossed by a series of parallel scars, which belong to a group of alternating beds of fine sandstone and marl, all dipping towards the west ; with the latter are associated some thin intercalations of fine ash in such a decomposed red stained condition that they might easily escape notice. These rocks closely resemble those at Tyne Mouth, and are probably on the same horizon, for Mr. Macconochie has obtained a suite of fossils from them almost identical with that col- lected from the latter locality. On the seaward side of the Car the amount of ash and the number of fragments, mostly consisting of lava, increase considerably, and, at the north end of this projecting mass of rock, boulders of lava containing large augite crystals are specially abundant. In several places the dip seen in the rocks 62 Cahiferous Sandstone Series. forming the Car is high, but this is clearly owing to false-bedding, for, about the middle of the long scar, a certain band, which can be traced at low water, is seen to lie almost horizontally. The centre of the bay in which the Car occurs is occupied by sand, but at low water some fine marl containing ostracods is exposed. Toward the western part of the bay the marl is succeeded by a considerable mass of soft red material having a sandy or marly aspect. In several places, however, this red colour suddenly gives place to green, especi- ally at joint planes, and the rock must be classed as part of the green ash (b) which has either altered in colour or is so mixed with marly material that the original colour of the ash has been lost, for the latter only retains its green colour if it be free from any considerable admixture of normal sediment. This curious change may be noted at several places in this locality, but the finest example occurs in the cliff face, where a large lenticular mass retains its green colour and several bands can be traced from the surrounding red material into it, changing colour as they enter. In the scars at the Gegan, boulders of the augite-bearing rock are again abundant in some of the more markedly ashy bands. The rocks here are considerably shattered, and the structure of the ground is difficult to make out, but a fault can be seen at the foot of the adjacent cliff, and its course is shown on the map. A little further west the greater part of the rocks are green ash which now forms the bulk of the shore and cliffs as far as North Berwick. The beds below the ash are, however, seen again in two other places along the coast. In the bay west of Tantallon Castle a white sandstone is exposed which may possibly be brought up by a small fault. It seems equally likely, however, that the ash at this locality lies in an eroded hollow in the sandstone, since at the north point of the bay both the ash and a thin bed of red marl underlying it are clearly seen banked up against a steep eroded face of the sandstone. At Canty Bay these underlying sandstones and marls are again brought to the surface, in this case undoubtedly by a fault, the course of which is clear on the scars but very difficult to trace inland. The beds present consist of sandstones, marls, cementstones and a few t hin bands of shale. The sandstones are highly calcareous and one band in the cliff face might almost be classed as a siliceous limestone, though the proportion of lime varies rapidly from point to point. From the shales interleaved in the sandstones Mr. Macconochie obtained remains of Catamites and Lepidodendron. Inland little is known of this portion of the series, owing to the drift covered nature of the ground ; three exposures are, however, worth noting. The first occurs on the south-west side of North Berwick Law and consists mainly of marly and shaly beds contain- ing plant remains, generally believed to come below the green ash. The second lies more than a mile to the south-east of the Law in a plantation north of the road near the smithy. Here some white sandstone is seen, obviously that of the Tyne Mouth scars. The third consists of a very impure sandy limestone which is exposed in a quarry rather more than a mile south of Canty Bay. It dips under some coarse ashy material, proved by a series of openings further north to mark the base of the green ash. North Bertoick and Garleton Area. 63 h. The green ash is the dominant constituent of the cliffs and scars of the coast for some miles east of North Berwick. When fairly pure ash, it is always cemented by the lime set free by the persistent de- composition in situ of the fragments of basic rock, largely vesicular glass, of which the ash was originally composed. This decomposition was also accompanied by the development of a large quantity of chlorite which imparts to the ash its characteristic colour. The stratigraphical position of the main mass of the green ash is fixed by a boring * at the east end of the High Street of North Berwick, the journal of which records, below 12 ft. of superficial deposit, " red volcanic matter becoming greener towards the base " for about 400 ft. The beds penetrated, however, have a high dip and their true thickness must be much less than that recorded. From the position of the bore it is clear that these represent the beds that rise from beneath the lava flows at Cowton Rocks. The higher and greater part of these beds consist of marls and red ashy sandstones, with a variable, but never large, proportion of decomposed ash. The amount of ash and chloritic material derived from the washings of decomposed ash increases rapidly in the lower beds of the group, so that they have a green tinge, as is seen near some little calcareous bands on the foreshore. This coming on of the green tinge is well shown by cores taken from depths of 350 and 400 ft. respectively. The rock at 350 ft. is rich in carbonate and chlorite, and is mainly composed of the washing of ash that decomposed elsewhere ; but the core from the greater depth contains in addition a considerable amount of ash decomposed in situ. The boring next passed through some 70 ft. of rock composed of bands of red and green ashy material associated with greenish shales and thin limy bands — the calcareous bands on the shore just referred to. Specimens from depths of 450 and 480 ft. have been examined and found to be largely composed of green ash which has decomposed in situ. Below this the beds consist mainly of pale green and mottled green ash associated with thin bands of more normal sedimentary material. The ash, however, is rarely pure but is mixed throughout with a varying amount of normal clastic mica, quartz, and felspar. A considerable proportion of the latter consists of microcline, the occurrence of which is important as it never occurs in the lower lavas of this area (10844-10851).t The rocks last described constitute the main and most persistent mass of green ash in this district. They are underlain at the borehole by normal sediments consisting of fireclay, fine micaceous sandstone and sandy marl, belonging to the sub-division (a) already described. Another boring some three miles to the east, near Seacliff House, penetrated the green ash for a distance of 170 ft. without proving either its top or base. The ash here shows far less admixture with normal sedimentary grains and is in many parts probably entirely free from such ; it is also destitute of lava fragments of appreciable size. The cores show well the phenomenon of the setting free of calcite by decomposition in situ, every specimen being permeated with minute veins of this mineral. It is seen on comparing cores from the * J. G. Goodchild, " Remarks upon a Recent Boring for Water at North Berwick," Trans. Qeol. Soc. Edin., 1899, vol. vii. p. 236. t Numbers in brackets refer to slides in the Geological Survey Collection. 64 Calciferous Sandstone Series. two bores described that beds in this green ash zone vary in com- position from place to place ; they are represented by nearly pure ash at one locality and at another by alternating beds, the thicker composed of a mixture of ash and normal clastic grains, while the thinner intervening layers are of more normal sediment. The ash is often intersected by small reversed faults, slides, or accommodation planes, with a low inclination, and clearly connected with its soft highly chloritic greasy nature ; this phenomenon may be observed even where no similar planes are met with in the adjacent sandstones or other beds, the grains of which do not easily slide over one another. Doubtless these planes were developed by the later pressure that produced the general series of domes and basins, which, as noticed above, are characteristic of the district. As the deposit is traced eastward along the coast from North Berwick frequent changes are noted in its composition, the most important being due to the oncoming of masses of larger fragments, either rounded, sub- angular, or angular, some of which are more than a yard across. Rounded and sometimes quite small bits of gritty and fine textured marls are abundant here, and a few of the fragments contain neither ash nor any other distinctly igneous material ; but in the majority of them some ash is present, and often in sufficient quantity to impart a greenish tinge to the pebbles. Rounded fragments of calcareous mudstone are not uncommon and are occasionally of large dimen- sions ; most of them have a somewhat flinty fracture, suggesting at first that they have been heated, but recent investigation has made it more probable that in many cases at least this hardening is due to silicification. In one curious pebble built up of the waste of a granitite set in a calcareous matrix, the decomposed biotites are so large that it is clear that they could not have travelled far before being deposited. Some of the clastic grains in these pebbles consist of angular fragments of quartz, and others of more rounded grains of felspar, microcline being common. The cementing material of the red pebbles is red oxide of iron, associated with a varying pro- portion of calcite, dolomite, chlorite, and probably colloid silica. The larger blocks of marly or gritty ash, which are closely related in composition to the deposit in which they are embedded, are of special interest. They are often subangular and at times angular and contain ash and lava fragments in varying proportions. The ashy blocks are often well banded, but they are not built up of alter- nating layers of pure ash and of ash mixed with normal sediment ; all contain some quartz, felspar, and clastic mica ; the colour banding is mainly due to the varying amounts of pyroclastic material present in the different layers. It is therefore clear that few of the ash frag- ments can have been blown into their present position, but that they were washed or swept along from an exposed surface, and mingled with the more normal sedimentary grains in their course. Rounded boulders of igneous material, many as much as a foot in diameter and some more than two feet, and mostly composed of lava, are extremely abundant. The great majority are markedly basic, and many are characterised by the presence of large crystals of augite, and thus resemble the lower bands of the overlying lavas. Although a great number of these rounded blocks were broken open, not a single true bomb was found during the resurvey, but Mr. Goodchild North Berwick and Garleton Area. 65 succeeded in finding two after repeated visits to the coast. Although these blocks of lava are greatly decomposed, there is no difficulty in recognising that while some are vesicular throughout, the majority are not so, and many are quite compact. At several localities these blocks are present in such large numbers that the whole deposit becomes an agglomerate, in which the long axes of the larger fragments lie in different directions and often across the bedding. Obviously the agglomerate must have been formed under peculiar conditions, and a clue to its mode of formation is seen in the lower part of the first cliff east of North Berwick, where the agglomerate is characterised by a great number of large angular blocks of banded ashy sediment, one group of which attracts attention from their size, identity in composition, and proximity to one another. They appear originally to have formed part of one larger block which broke up in course of transport. The friable nature of their material renders it unlikely that the whole block could have been blown into its present position ; and it is more probable that they have been carried there, but under conditions that enabled them to escape any appreciable erosion. An explanation of their mode of transport is suggested by the work of Drs. Anderson and Flett,* who show that, after the St. Vincent eruption, the surface of the ground was partly covered and the valleys nearly filled with fine ash or highly disintegrated material which could easily be carried away by water. Mud floods were thus produced, of which they have given a graphic account, noting the caving in of the banks of streams and the fact that stones floated on the surface of the mud instead of being rolled at its bottom along the bed. It is to this peculiar power of transport that the blocks seen in the cliff east of North Berwick seem to owe their origin and transport. We may suppose them to represent fragments broken off from the banks of streams, and floated down on the volcanic mud to their present position without material abrasion. In the case of the Soufriere the greater part of the ash was swept away by a rapid succession- of intermittent floods in the course of a year ; but the numerous lenticles of limestone in the green ash appear to show that long intervals elapsed between the volcanic mud floods which we suppose to have formerly taken place in the North Berwick area. These lenticles seem comparable to the local deposits at present forming in hollows in many districts where an arid climate prevails, and where any rainfall that does occur flows over ground composed of decomposing basic volcanic rocks. In the Springbok Flats of the Transvaal these conditions are partly fulfilled ; the rainfall is deficient, but, such as it is, it flows over a surface largely formed of a decomposed amygdaloid, containing much lime set free by decomposition. During the periods of rainfall much of this lime is extracted, which, when the dry season sets in, is deposited on the surface of the flats by evaporation.") - The amount of lime so deposited is considerable even here, but it would obviously be greater were the climate more arid and more hollows present to retain the intermittent rainfall. Such deposits must on the whole * " Report on the Eruptions of the Soufriere in St. Vincent in 1902. and on a Visit to Montagne Pelee, in Martinique," pt. i., Phil. Trans. Roy. Soc. Lond., Ser. A., 1903, vol. cc, p. 353. f See "Transvaal Mines Department,' - Report of Gcol. Survey for 1904, p. 13. 5 66 Galciferous Sandstone Series. show a singular freedom from organic remains, and a similar freedom is generally characteristic of the lenticles of lime in the green ash of the North Berwick area. A shower of ash would, under desert conditions, supply a specially large amount of material capable of giving rise to mud floods, and this consideration perhaps enables us to understand why the number of large fragments in the ashy agglomerate is generally much greater than in the peculiar conglomerates, already described, in which almost the whole of the material is of normal sedimentary origin. It should be clearly understood that the number of fragments of sedimentary material in these ashy agglomerates and their variability in composition show that they cannot have been blown into their present position. G- B - The stratigraphical representative of the great green ash of North Berwick is exposed here and there in the district lying south and east of Traprain Law. As compared with its development in the typical area it shows a greatly diminished thickness, a much larger admixture with normal sedimentary material, and an almost uniformly red colour. Toward the east near Whittinghame, as the volcanic centre of Dunbar is approached, the deposit increases in thickness and often includes great masses of rock, both igneous and sedimentary ; it is not improbable, indeed, that this great sheet of fragmental material, partly volcanic in origin, may have been derived from a number of different centres, and that the Dunbar centre may, among others, have supplied its quota. Near Beil, two miles north-east of Whitting- hame, another and much less important bed of ash has also been recognised, at a somewhat lower horizon in the Cementstone group. To the south of the powerful Dunbar-Gifford fault the basement ash is accompanied at its outcrop by an extensive monchiquite sill, and the two keep together until cut off further south again by the Lammer- muir fault. None of the lava members of the volcanic group extend so far as to reach this fault, so that the ash seems to have originally possessed a wider distribution than the lavas, as might have been expected. e. b. b. c. The Limestone Horizon. — The boring at North Berwick, already referred to, pierced a number of thin limy bands before entering the main mass of green ash. These are the thin bands seen on the shore at Point Garry. It is probable that some of the limy bands of the bore are calcareous sandstones rather than limestones, for there are far more bands recorded in the bore journal than are seen on the shore, unless the calcareous sandstone bands are included. To the east of the town the position of the calcareous horizon is marked by a gap in the shore section filled with sand, the beds west of the gap being above the limestone while the underlying green ash crops out to the east of it. A little inland, and to the south-east, lies Rhodes quarry, in which a thick mass of unfossiliferous limestone was formerly wrought ; the true position of this bed is somewhat of a puzzle as no bed like it is known anywhere else in the area, despite the fact that here it attains a thickness of about thirty feet without including the overlying more impure calcareous material. It seems probable, however, that it lies on the horizon of the calcareous rocks North Berwick and Garleton Area. 67 of the borehole, and this view is strengthened by the occurrence of a somewhat similar limestone, at apparently the same horizon, much further south. If the bed were persistent it should undoubtedly cross the mouth of the Glen a little west of Rhodes, but no such thick lime- stone can be found although the ground is free from superficial deposits. There are, however, a few thin impersistent bands of limestone in the green marly ash near the mouth of the Glen, in one of which Mr. Macconochie found ostracods. The main limestone in the quarry has a foetid odour, and approximates closely in aspect to beds known to occur in various foreign regions where water flows over decomposing basic igneous material into hollows in which it evaporates, leaving behind deposits of lime, as mentioned on a previous page. It is a massive bed of compact texture, dark bluish grey colour and splintery fracture, and contains crumpled laminae and irregular patches of chert. In some respects it has a considerable resemblance to the limestone of Burdiehouse, Mid-Lothian, but it has yielded no un- doubted fossils, though the overlying calcareous beds contain mark- ings, resembling linear grass-like leaves, which perhaps represent pinnules of Telangium affine. These higher beds contain thin laminse of chert also, and show, in places, crumpled or finely mammillated surfaces. Certain brown soft decomposing bands contain long crystals of sulphate of lime which have resulted from the action, on limestone, of decomposition products of iron pyrites. But the most str ivin g feature in these higher beds is the presence of one or two thin bands of oil-shale, which have yielded some coprolites and small indeterminable fish scales. In cutting a drain across the road a little north of North Berwick Mains a bed of limestone of no great thickness was met with exactly on the line of strike of the gap on the coast, where, as already stated, the limestone must occur. Another outcrop is seen in the small inland scar at Seacliff House. It consists of a number of thin bands of limestone associated with green ashy mud and overlain by red ashy sandstone. The great thickness of ash proved in the adjacent boring shows the top of the green ash must be close by, but it is im- possible to trace the limestone further, as it is covered with drift on one side and on the other cut off by a fault. In three places to the north-west of the Whitekirk mass of lavas calcareous rocks have been met with, and all appear to belong to the horizon here described. The largest exposure is in a disused quarry near the farm of Carperstane, and shows a main bed which appears to be about 20 ft. thick. It is of a yellowish brown colour, and in many places possesses a curious irregular banded structure which in small specimens often resembles that of an agate, strongly suggest- ing that it is an evaporation deposit, as already described. Fossils in it are either very rare or absent. The main bed is overlain by some greenish mudstone in which calcareous layers occur, the whole section strongly recalling that at Rhodes. Further, as at Rhodes, this thick limestone cannot extend far, for at the second locality — Balgone Barns, to the north-east — it proved too thin to be worth working. At the third locality it is equally thin, and was probably exposed unintentionally, when deepening the road into a large quarry in trachyte. The limestone here is associated with green ashy mud, like that overlying the thick limestone at Carperstane. g. b. 68 Calciferous Sandstone Series. In the East Linton area, close to the eastern edge of the lavas at Lawhead, a limestone was formerly worked in a large quarry and must be of considerable thickness ; but the quarry has been filled up and no information could be obtained as to the character of the bed. Between East Linton and the Dunbar-Gifford fault the limestone is frequently exposed, especially in a series of old quarries of which that at Sunnyside is the best known. It is always unfossiliferous and, except in one quarry, to be referred to later, is characterised by a very compact texture and a curious banding and lamination similar to that noticed at Carperstane ; in many cases also it has assumed a bright red colour through staining. In the railway cutting east of East Linton it occurs in two leaves, separated by several feet of red ash. The upper of these is about 12 ft. thick and repre- sents the bed formerly wrought in the neighbouring quarries. The only exposure in which the limestone shows other than its usual characters occurs in a little quarry west of Whittinghame Mains, where a thickness of 10 ft. is exposed ; the bed in this quarry is earthy in texture, mauve in colour, and though still well laminated it does not possess the curious agate type of banding which is so character- istic of the Carperstane and Sunnyside exposures, and which is found again typically developed at Ruchlaw, a little east of Whittinghame. H. B. M., E. B. B. d. The Beds above the Limestone are exposed on the shore at North Berwick on both sides of Partan Craig, and again a little further east, at the shore end of the natural breakwater. The lower bands contain much detrital igneous material and at times have a distinct green tint ; but as we ascend in the group the green colour disappears and the beds are all stained red, and consist largely of pink and red marl. With the latter we also find red sandstones in which fragments of ash occur sparingly, associated with much clastic quartz, mica and felspar — microcline being more abundant than usual, though quite subordinate in quantity to the quartz. The same group appears again in a clear unbroken section on the east side of the pier. The increased proportion of pyroclastic material in the lower bands is well marked, while in the upper the marls show the characteristic green patches. In a bed of fine grey shale, possibly somewhat tufaceous, which occurs about 150 yds. east of the pier, Mr. Macconochie found a number of plant remains, including a new species of fern which has been named, by Dr. Kidston, Sphenopteris filiformis. Inland, beds of the group (d) are but rarely exposed. They are cut open alongside the railway just outside North Berwick Station and may be met with at intervals on the hillside to the south. They are also exposed in several old quarries south of East Linton. G. B. CHAPTER VIII. CALCIFEROUS SANDSTONE SERIES.— (Continued) The North Berwick and Garleton Area. — (Continued) II. THE VOLCANIC SHEETS AND PYROCLASTIC ROCKS BETWEEN THEM. In the North Berwick and Garleton area we find a great mass of igneous material which is mainly composed of lavas ; but the recent revision has shown that, as in the Tertiary volcanic districts of the Western Isles, numerous intrusive sills are associated with the lavas. In East Lothian, many of the sills appear to have been intruded at such a small depth below the surface that in composition and main field characters they cannot be distinguished from the true lavas, and must therefore be referred to the same geological episode as the latter. The justice of this last remark is shown by the fact that above the top of the group, in many cases only a few feet above, we find a locally developed conglomerate composed of waterworn frag- ments among which are representatives of many of the rocks regarded as sills. Further, no sill having the petrographical characters of the lava group is known above this conglomerate. There are, however, certain basaltic intrusions, later than this conglomerate, and clearly distinct from those of the earlier phase. In this area, indeed, these later sheets are always intrusive, even when occurring in rocks con- siderably above the lava group, although they closely resemble the lavas of the Burntisland and Bathgate districts. In the majority of cases the two groups can be distinguished even in the field owing to differences in their modes of decomposition. In the lavas, much the more abundant rocks, the olivine as a rule decomposes with a red crust (the iddingsite mode of decomposition), while in the dark sills this mineral usually decomposes with the development of chlorite, imparting a green tinge to the rock. Moreover, the basalts of the lava group are conspicuously porphyritic, those of the later intrusions only inconspicuously so ; and it is among the latter only that columnar structure attains perfect development. While a clear distinction can be usually drawn both in the field and the study between the rocks which never occur above the con- glomerate, and the distinctly later rocks that sometimes do so occur, yet it becomes obvious from their petrological affinities that the two sets belong to one great family of igneous rocks characterised throughout by a somewhat high percentage of alkali. It is clear that the lavas and sills were fed from a large number of vertical ducts, or stocks, round or oval in cross section, and no trace of fissure eruption has here been encountered. It is to be noted that the lowest existing lavas are underlain by considerable masses of detrital material, closely approximating in composition to the lavas 70 Calciferous Sandstone Series. above ; and chiefly represented by the green ash with its included blocks of lava already described. In consequence of the advances of petrological science in recent years, we have modified the divisions which former workers adopted when mapping the lavas of this district. The outcrop of the lavas can be separated broadly into two great areas, which interlock to some extent in the district of East Linton and again to the south of Traprain Law. The western area is essentially composed of more acid trachytic rocks, while the dominant component of the eastern area is a group of basaltic lavas curiously intermingled, however, with others of markedly less basic composition, which tend in some measure to bridge the gap between the two larger groups. As the dip of the lavas is on the whole from east to west, this geographical division corresponds to a sequence in time of basalt lavas followed by trachytes. The Basaltic Lavas. — A good general idea of the rocks composing the lower portion of the lava sequence may be obtained by making a series of traverses across the clearer exposures, starting, in all cases, from the base of the series. Commencing with the coast area, a specially clear section of the lower portion of this group of rocks occurs at the natural breakwater which forms the North Berwick Pier. The beds are here dipping to the north-west at an angle of about 20°, and the following bands are easily recognisable : — 1st Band. — The south-east footing of the breakwater is formed by the lowest bed in the group ; this is a basalt of Dunsapie type, and, where fresh, is a rather dark rock, containing numerous felspar phenocrysts of medium size, little grains of olivine, more or less rounded and coated with -an almost brick -red skin, and a few crystals of augite, not common and rather un- evenly distributed (10,574). The basal portion of the rock is distinctly vesicular and decomposed at some points, while at others vesicles are rare and the rock much fresher. The vesicles are probably due to original gas- bubbles, but they are not markedly elongated and in this respect are totally unlike those which characterise the top of the overlying bed. Thick- ness nearly 100 ft. 2nd Band. — The next sheet is » fine grained mugearite. It is a homogeneous rock, almost destitute of macroscopic porphyritic crystals. When fresh it is somewhat light grey in colour, but in its more common, rather decom- posed phase it is a brick-red rock often with a somewhat shaly aspect, owing to the parallel arrangement of the little microlites of felspar, of which the microscope shows it is largely composed. A curious oval structure, shown by the alternation of pale and red bands, with a thickness of about one-tenth of an inch, is often present. The difference in colour is due to the abundance of iron-ore in the red bands and its comparative rarity in the lighter ones. The longer diameter of some of these structures attains a length of three feet. Another special feature of this second band of rock is the peculiar nature of its upper surface, which is extremely vesi- cular, with the vesicles so greatly drawn out that they resemble tubes, the molten rock having doubtless at one stage of the cooling been of an unusually viscous nature in consequence of its distinctly acid composition. These characters enable the rock to be easily identified in the field, and readily mark it off from the more basic lavas above and below Its thickness here is about 80 ft. 3rd Band.— The acid rock just described is succeeded by a rather compact lava, allied to the first band, but slightly less basic, the porphyritic felspars being larger and accompanied with a little microscopic augite. In com- position it is intermediate between the Dunsapie and the Markle types of North Berwick and Garleton Area. 71 basalt. The phenocrysts of felspar are about half an inch in average length, tolerably broad in one direction but thin in the other. Rounded crystals of olivine seem almost as abundant as in the first rook. The thickness is perhaps a little less than 100 ft. The character of the rocks above the third bed cannot be deter- mined in this locality, but a fault at the shore-end of the Pier throws the whole group up again, and the base is once more encountered at the east end of Cowton Rocks, the scars at the west end of North Berwick. Though these rocks are more decomposed than those forming the Pier, there is no difficulty in recognising the identity of the basal rock, which makes an outcrop here about 130 yds. broad. It is succeeded by some much decomposed finer material, consisting of either one or two beds, which at one point closely resembles the mugearite of the Pier. Above this again comes the third rock of the same locality. Still further west we find a band not hitherto seen, which is distinguished by so great a number of phenocrysts of plagio- clase felspar that it may be conveniently called the felspar basalt. Microscopically it is a basalt belonging to the Markle type. The broad outcrop on the scars is much decomposed, but along the strike inland a number of knobs of the same material project through the blown sand, at the west end of the town, and from these knobs very fresh specimens of the felspar basalt can be obtained. A brief ex- amination shows that it is less basic than either of the preceding basaltic lavas, so that, if we leave the mugearite out of account, it forms the third member of a series in which the basicity decreases as we ascend. Turning inland to the area about Whitekirk, the map shows that the lava series is much thicker than on the coast. At the foot of the hill about a quarter of a mile north of Whitekirk, the first bed met with is a fine grained non-porphyritic rock (mugearite) characterised by dark spots, which is very different from any member of the basic group at present under consideration. Above this comes a great mass of markedly basic material, forming the entire ridge of White- kirk Hill. Although the ground is obscured by drift and the features are largely due to glacial erosion, it is clear that several sheets of lava must be present here. All, however, appear to be characterised by the presence of crystals of augite, as well as of olivine and some felspar, and the basal band seems to contain rather more augite than the others, and belongs to the Craiglockhart type of basalt. At the north- west foot of the hill, the various patches of bare rock contain felspar in more abundance and augite crystals more rarely or not at all. The lava to which these patches belong is, in fact, less basic than those composing Whitekirk Hill, though closely related to them. Further west and at a higher horizon, as at North Berwick Pier, a non-por- phyritic mugearite is met with, not belonging to the group of basalts. This in turn is overlain by the felspar basalt, which in this special area is succeeded by a fine porphyritic mugearite. The group of basalts still shows, therefore, in Whitekirk Hill the same tendency to decreasing basicity as we ascend in the series that we have already noticed on the coast. But the group as a whole is much thicker ; the greatest increase is clearly in the lower and more basic members, those which are richest in augite crystals being altogether absent at North Berwick, unless they are represented by a thin greatly decom- 72 Calciferous Sandstone Series. posed bed which occurs on the shore a few yards east of the Pier, and is separated from the overlying main mass of lavas by a thin bed of marl, possibly somewhat ashy. The gradual upward transition at Whitekirk is again interrupted by the occurrence of a non-por- phyritic element, extraneous to the basaltic series, viz., the mugearite, which here appears thrice in the succession. Similar facts may be observed in the railway cutting west of East Linton. The dip here is easterly and at the west end of the cutting we see a small outcrop of the spotted non-porphyritic muge- arite ; above this comes the augite-bearing band, and then further east another band richer in felspar, while the typical felspar basalt caps the hill rising on the south side of the railway. Again, on the north bank of the Tyne, close to Hailes Castle, the rock containing augite crystals is succeeded above by the other bands richer in felspar phenocrysts, and the general law of decreasing basicity upwards in the basalt group still holds good. G. b. This law is further illustrated to some extent in a good section in the railway cutting east of East Linton Station. The chief value of this section is however due to the circumstance that it affords a clear illustration of certain of the phenomena of contemporaneous volcanic action. Seven or perhaps eight lava flows can be dis- tinguished, but as both the top and base of each is slaggy or vesicular, it is sometimes difficult to point to the exact dividing line between two successive flows. The beds dip at a gentle angle towards a point some degrees north of west and at the eastern end, the Sunny- side limestone crops out, as has already been described. It is suc- ceeded by a dull red fine-grained mugearite possessing a rather platy fracture, the surface of which exhibits the shimmery lustre character- istic of the group. A mass of banded red ash succeeds the mugearite on the south side of the cutting. On the north side there is a short gap, beyond which are outcrops of similar dull red mugearite, occurring perhaps in two flows. Yet another flow of the same type follows, its vesicular base being seen to rest on the amygdaloidal top of the lava beneath, while it passes upwards into a similar soft purplish slag. The succeeding lava is a very different rock, being a dark massive porphyritic basalt of the Craiglockhart type, containing numerous phenocrysts of augite. Its top is well seen on the west side of the bridge over the cutting, where it is vesicular, and overlain along an irregular line by a thin bed of ashy bole. This basalt is followed by three flows of the Dunsapie type, in which felspar appears among the phenocrysts, while augite plays a less important role. The first of these lavas is distinguished from its fellows above and below by its purplish colour. Its slaggy base is succeeded by a belt of rock containing numerous phenocrysts of plagioclase, which decrease in numbers again before the thick slag is reached which marks the top of the lava. The next flow above is a purplish finely crystalline basalt containing very few phenocrysts. It is only slightly vesicular at the base, but the top is a soft amygdaloid exposed near the platelayers' cabin. The next and highest flow in this section is a reddish basalt containing abundant phenocrysts of plagioclase, augite and olivine (pseudomorphosed). h. b. si. South of the railway cutting and as far west as Old Hailes there are several good sections and numerous continuous exposures, in North Berioick and Garleton Area. 73 all of which the same general sequence may be recognised, despite the marked impersistence of individual lava flows. A small neck situated between Old Hailes and Traprain Law may, perhaps, have been the source of some of the agglomerate and overlying basaltic lavas which occur in its immediate neighbourhood. To the west of Traprain Law the basic group of lavas must thin rapidly away, and in the driftless country lying further to the south only two flows intervene between the basement ash and the over- lying trachytes. The diminished group, however, is an epitome of that occurring to the north and shows a similar close association of a rock of the trachydolerite group with porphyritic basalt. The rock of the trachydolerite group is in this case, however, a kulaite and not a mugearite, so that it cannot be regarded as the southern extension of any of the flows outcropping to the north of the Law ; it is overlain by a very handsome basalt of the Craiglockhart type, similar to the lower lavas of Whitekirk Hill, but with even more conspicuous phenocrysts of augite and olivine. Another interesting feature of this district is the occurrence of a slaggy felspar basalt of Markle type some little way up in the trachytic group. In this par- ticular area the trachytes have characters suggesting that they are true surface flows, so that it appears probable that the occurrence referred to is an example of a local recurrence of basaltic conditions after the outpouring of one or more trachytic lavas. The evidence for the existence of the basaltic group on the south side of the Dunbar-Gifford fault is based upon two exposures of very decomposed rock which appear to be of a basic nature. The furthest west of these is exceedingly slaggy and must belong to the lava group ; it is directly overlain by a trachytic rock also much decomposed. As has already been stated, there is no representative of these lavas where the ash crosses the Gifiord Water at Yester. At this locality the great mass of volcanic rocks, which constitute the Garleton Hills, are merely represented by a few feet of ashy sediment. e. b. b. It thus becomes apparent that in the area to the east of the great mass of trachytes, and underlying the latter, there is a series of basaltic lavas which are thickest in the Whitekirk area and thin away to the north, west, and south. They are almost invariably associated with mugearites, but the discussion of the relations of the latter is reserved for the next section. Where they attain their fullest development the lowest bands are markedly basic and characterised by the presence of abundant phenocrysts of augite.* Although there may be small local exceptions the basaltic rocks become, as a rule, decreasingly basic as we ascend in the series. The band which most commonly forms the highest member of the group contains macroscopic crystals of plagioclase, and has been already frequently referred to as the felspar basalt. The more basic types are somewhat local, but the felspar basalt must have covered a wide area as it is still preserved over a considerable part of the district. Taken as a whole the basalts are not markedly vesicular — a feature which is possibly connected with the great thickness of many of the individual sheets, some being as much as 100 ft. The thinner flows appear to be decidedly vesicular, as will be seen on examining the * The importance of the large augite crystals marking the lowest members of the series was recognised by Mr. Howell in his mapping of the area 40 yenrs ago. 74 Calciferous Sandstone Series. lowest band at Kingston Hill and on the east side of Lawhead Hill. The top and base of any flow are probably, as a rule, much more vesicular than the interior, but these more vesicular parts are rarely seen inland as the junction of two bands nearly always forms a hollow covered with vegetation. In the few cases observed on the coast and in railway cuttings, the rule just referred to is fairly well marked, and it is also noticed that the tops of the flows are usually distinctly more vesicular than the bottoms. At times hoUows far larger than ordinary vesicles are met with, for example, on the coast, nearly two miles west of North Berwick, just where the Longskelly scars touch high water mark, the top of the felspar basalt contains some cavities which are 9 ins. in diameter. The base of the fine grained trachyte of Weak Law is seen just above the felspar basalt, and it also contains hollows 3 ins. in diameter. In the more basic rock the hollows are filled with calcite, but in the trachyte with silica, the infilling material in each case having evidently been derived from the body of the surrounding rock. Inclusions of foreign material are very rare in the basalts — a fact which may be due to the great fluidity of the molten lava, for in the more acid, and originally more viscous, lavas, inclusions of sedimentary material are common. Trachydolerites. — The rocks that interrupt the continuity in the sequence in the basaltic lavas, throughout the whole volcanic area, belong to the great trachydolerite subdivision, and, with a single exception, are mugearites. Two main varieties of the latter can generally be recognised in the field, one being lighter and more acid than the other. The less acid may be conveniently called the Law- head variety, as the finest exposure occurs about Lawhead, a mile and a half N.N.E. of East Linton. The more acid may be called the Congalton variety, as the more typical features of the rock are well seen in a quarry close to Congalton Mains, some three miles south of North Berwick. At the first visit to this quarry, the close resemblance of the rock exposed in it to the mugearite of Eigg, which had been determined by Mr. Harker, was at once recognised, and a microscopic section confirmed the resemblance noticed in the field. By far the most instructive outcrop, however, occurs at North Berwick Pier. In the ground north of the Tyne the Lawhead variety pre- dominates in the eastern part of the basaltic area while the Con- galton is the dominant variety in the west. Both are usually fine grained and non-porphyritic, but in certain localities small phenocrysts come in gradually and sparsely, the slight variations from place to place being probably due to the viscous character of the molten lava, which rendered the equalisation of composition more difficult than in the more fluid basalts. Similar local differences occur in the trachytes, the great viscosity of which, when in the molten state, is well known. The mugearites usually weather with more or less marked brick-red colour, distinctly paler than that of the decomposed basalts. A remarkable feature of these rocks is the tendency to set up a segregatory structure, which is shown by the occurrence of a number of fine parallel films building up oval masses which in extreme cases are over 3 ft. long. Admirable examples of this structure are shown by the mid-rock of North Berwick Pier, where the films North Berwick and Garleton Area. 75 are alternately pale and red, the latter colour being due to the oxida- tion of the iron ore which has segregated in alternate layers. In another variety of this rock, spots about the size of a finger tip are developed, owing, again, to the local segregation of the iron ore in one part and its diminution in another. This spotted structure is probably original and not due to weathering, as in the case of the trachytes to be described later. When this structure is absent and the rock moderately fresh, it is of a pale reddish grey colour if it belongs to the more acid members of the subdivision, and rather darker grey when less acid ; in no case have the typical mugearites been found fresh enough for the red tinge to be absent. Very char- acteristic is the intensely vesicular top they always possess, which is admirably shown by the rock at North Berwick Pier. Here the vesicles are in the form of fine tubes, like those at the top of some of the trachytes ; they rarely show the dragging out parallel to the flow so common in most lavas, and in a large number of cases they are vertical. The main outcrops of mugearite are shown on the map, and frequent mention of them has already been made in the description of the basalts with which they are associated. One band which is seen near Mill Burn, south-west from Dirleton, occurs high up in the trachytic series, and is therefore of special interest, but the ex- posure is surrounded by drift and it has not been found possible to show the bed on the map. g. b. The other type of trachydolerite is the kulaite to which reference has already been made. It can be readily recognised in the hand specimen by its hornblende crystals, and is restricted to the district south of Traprain Law, where it covers a large area, although prob- ably consisting of a single flow. The best exposure occurs at the east end of the scar which is crowned by the Balfour monument. The rock shows a well marked horizontal platy structure, and is seldom markedly vesicular, but its contemporaneous nature is inferred from the fact that it is traversed in the cliff section by a vein of ashy cement- stone, strongly suggesting that the igneous rock was exposed at the surface when the material of the vein was deposited. e. b. b. It will thus be seen that by starting at the east foot of the White- kirk Hill and proceeding westwards, beds of trachydolerite, in most cases mugearite, are met with, some at the base of the lavas, and others at varying horizons, almost, if not quite, to the top of the trachytes. The latter position is, however, quite exceptional, and the basaltic group may be regarded as the normal home of the mugearites of East Lothian. Trachytes. — As the survey of the area progressed it became clear that some of the trachytes were undoubtedly intrusions, and where the boundaries of these could be traced they have been differentiated on the map and separately described. There are doubtless other intrusions, which, owing to the cover of drift and the difficulty of tracing their junctions with other members of the group, have been included with the group of undifferentiated trachytic lavas. The main masses of trachyte stretch from the coast north of Dirleton, to Haddington, and hence with a more restricted outcrop 76 Calciferous Sandstone Series. to the west of Traprain Law, and almost as far south as Gifford. In addition, a large laccolitic mass occurs at Pencraig, to the north-east of Haddington, while smaller intrusions of similar material are met with at Traprain Law, North Berwick Law and the Bass Bock. The evidence seems conclusive that the trachytes are almost without exception newer than the basalts of the lava group ; the latter indeed clearly dip under these more acid rocks in all parts of the area, and we know only one case of a basaltic lava being interbedded with trachytes, where the latter are also regarded as lavas. The case referred to occurs in the district south of the Tyne. Further, it has already been shown that while well-rounded fragments of basic basalt, almost identical with the lower members of the volcanic sheets, have been met with in abundance at least 150 ft. below the base of the latter, not a single fragment of the trachyte is found associated with them. On the other hand well rounded fragments of the trachytes have been found throughout a considerable thickness of the sediments which immediately overlie the volcanic series. It thus becomes apparent that the trachytic group of rocks belongs distinctly to one special epoch of volcanic activity, and has a very limited range. They may be divided into three main groups, as follows : — (a) The non-porphyritic and inconspicuously porphyritic trachytes. These varieties reach from Eyebroughy Scar, on the coast, inland beyond Traprain Law, almost to the Lammermuir fault. Their extension must have been far greater at one time, for both North Berwick Law and the Bass Bock are composed of trachytes of this character, and probably represent ducts which supplied sheets at a higher level. (6) The porphyritic trachytes. These varieties are not confined to any one locality but occur sporadically over a large area, as if fed from numerous ducts or stocks. They are characterised by the presence of easily recognised phenocrysts of sanidine felspar. (c) Certain porphyritic and non-porphyritic trachytes distinguished by the specially fine grain of their matrix : often amygdaloidal. These specially fine grained types are apparently now restricted to one district which may be conveniently called the Drem area. The matrix when fractured has a characteristic almost cheese-like aspect, and a fair number of vesicles appear to occur throughout the body of the rock. Small porphyritic crystals may be present even in considerable numbers, but the ground mass proper is always fine in texture. This type of trachyte is represented in the ash-like beds of Weak Law, by a vast number of small angular fragments, and it must have been rather extensively developed in the Drem area. The fragments are very fine in texture and resemble some devitrified rocks, but they probably owe this appearance to silicification. The subdivisions given above were made in the course of field work, but in describing the petrological characters observed under the microscope a different grouping has been adopted, as will be seen in a later chapter. We shall now proceed to describe these different divisions of the trachyte family at greater length, one by one. (a) The Non-porphyritic and inconspicuously Porphyritic Trachytes have been included together, because we can never follow rocks of the former type for any distance without meeting patches, or even con- siderable masses, in which little phenocrysts are recognisable. From their similarity in field characters, mode of occurrence and weathering, the two varieties are evidently so closely related that they are con- veniently grouped together. North Berwick and Garleton Area. 77 The best specimens of the type containing small scattered pheno- crysts can be obtained from the bottom of the large road-metal quarry at Skid Hill, on the crest of the Garleton Hills. At the base of the quarry the matrix is pale greenish grey and the felspars are glassy ; higher up in the quarry face the rock becomes first greenish yellow, then yellow and finally brownish ; but it never attains the rich tint of the North Berwick Law rock, described later. A little to the east, at Craigie Hill,* the trachyte contains very few phenocrysts of felspar, though in fresh specimens the rock closely resembles that just de- scribed. A specially large mass of this non-porphyritic type occurs to the south of Skid Hill, and forms the greater part of the. water-shed of the Garletons for some distance to the east, appearing to extend almost to the foot of Traprain Law. On the Garletons much of the outcrop is free of drift and the field characters of the non-porphyritic trachytes are well shown. In many cases the rock weathers into small oval patches, clearly due to tension planes which were developed during the cooling, though they are only revealed in the decomposed rock, in which they become stained by infiltration of iron oxide. These stain-planes are further apart in the direction of the long axis of the oval than in that of the shorter, and along the latter they often coalesce. Such oval structures are distinctive of the weathered type of trachyte being described. They have some resemblance to the oval structures of the weathered mugearites, but the layers in the mugearite structures are much more perfectly parallel than those in the trachyte. Rocks having these field characters often occur immedi- ately above the felspar basalt, and in many parts, where the ground is completely obscured by drift, it has been assumed that the two beds retain the same relative position. The boundary line between them is shown on the map and helps to bring out the general structure of the district. The actual junction is seen on the coast at Weak Law, north of Dirleton, where the silica-filled cavities, already referred to, characterise the base of the rock. Near the new Golf House, the trachyte weathers almost like shale, doubtless owing to the parallel arrangement of the felspar microlites and the decomposed state of the rock. The most interesting point, in the coast section of this trachyte, is, however, its curious top, which is not of the ordinary vesicular type but built up almost entirely of elongated tubes with a general vertical trend. In many places the tubes are grouped together and are rarely, if ever, horizontal. Moreover, the top of the bed is singu- larly well preserved and shows little if any sign of erosion, though it is traversed by two of the cracks filled with fine muddy or marly material which are described in the sequel. This absence of signs of contemporaneous erosion of the upper surfaces of the lavas or sheets of igneous rock is a feature of the whole volcanic series of this area, and forms a striking contrast with the state of matters in the Old Red Sandstone lavas south of Stonehaven. The action of the sea water seems to prevent the formation of the typical oval patches in the rock at Weak Law, but in the exposures projecting through the blown sand, just at the nose end of the 100-ft. contour, perfect examples of these bodies are seen. An outcrop at Byebroughy Scar, nearly four miles west of North * Not named on the one-inch map, but only a few hundred yards south-east of Garleton. 78 Galdferous Sandstone Series. Berwick, closely resembles a somewhat decomposed soft reddish sandstone, and would, from field examination alone, have been classed with the Skid Hill type of trachyte, but Mr. Bailey has shown that it is a quartz-bearing rock allied to the quartz-bearing porphyritic rock at Dirleton. <*• b. The trachytes which continue south of the Tyne are all of the non- porphyritic variety. The junction of their lowest member with the underlying basalt of the district can be followed in detail across the ground south of the Balfour monument. Here again the trachyte is markedly vesicular. As has already been mentioned, this district supplies a probable instance of the recurrence of a basalt lava within the trachytic group ; its outcrop is not very extended. Upon the other side of the Dunbar-Gifford fault the trachytes are represented by a single flow, which when traced farther south seems to become inter- calated among the sandstones which directly overlie the basement ash; it eventually dies out before reaching Gifford Water, e. b. b. (6) The Porphyritic Trachytes. — Some two miles west of North Berwick is a rock ridge which in places rises abruptly above the super- ficial deposits, but which is so covered with trees that its true form is almost concealed. This rock has been extensively quarried both for building-stone and road-metal, and, in consequence, specially fresh specimens can be obtained. In the quarry now in use, Craigs Quarry, near the village of Dirleton, it has a moderately fine greenish grey matrix in which are set a great number of porphyritic crystals of sanidine felspar, about a third of an inch long. All the higher ground immediately west of the village is composed of the same material, and the evidence suggests that this is the crest of a stock which sent out a sill-like protrusion in all directions. This view is supported by the fact that at the bottom of the old quarry a thin horizontal band of marl lies completely embedded in the trachyte, and intensely baked. This marl must have a considerable extension, for a large proportion of the blocks forming the road-walls to the east of the village contain fragments of it, and it was probably its frequent occurrence within the old quarry which led to the abandonment of the latter. Clearly no lava flow could have picked up such a long sheet of marl. It is uncertain how far the porphyritic trachyte formerly extended ; it cannot have gone far to the north, for it does not occur on the coast, and no fragments have been found loose in the intervening ground. To the unaided eye this porphyritic trachyte does not appreciably differ from the others, but it has been proved to contain a notable proportion of quartz in the ground-mass, and differs thus from the Peppercraig rock (Lunatic Asylum, Haddington), to be described shortly, which it resembles in the field. In the railway cutting south of Dirleton Station, we see a good section of porphyritic trachyte which resembles the rock of Craigs Quarry macroscopically, though it probably contains no free quartz. It must cover a considerable area, and has been quarried in many places. There can be little doubt it is intrusive and it is probably connected, though not at the surface, with the trachyte quarried on both sides of the road at Burnside, about a mile south of Kingston, which is close to the limestone below all the lavas, and must therefore also be intrusive. There is good reason to believe that this mass continues, gradually thinning, as far as the great limestone quarry at North Berwick and Garleton Area. 79 Carperstane, where a thin band of similar trachyte intrudes into the upper calcareous beds. In all the above-mentioned outcrops the porphyritic rock varies somewhat in aspect ; near the surface the matrix is often greenish yellow and the felspars stone-white, but in deeper openings the matrix frequently has a green tinge and the crystals are of a yellowish colour. Farther south, in the Haddington area, the best-known porphyritic trachyte is that of the Peppercraig Quarry,* described by Dr. Hatch. The rock varies somewhat in appearance, being reddish when most decomposed and green when least so ; it is not so pale in tint as the quartz-bearing rock of Dirleton, but the two could not be separated on field evidence alone. Porphyritic sanidine crystals are generally abundant ; but in certain portions of the rock they are subordinate to plagioclase crystals. The cover of drift makes it impossible to trace the extent of this rock, but to the north-west it probably continues to Alderstone quarry, where an apparently identical rock occurs. The finest example of a porphyritic trachyte in the Garleton area is met with in the Bangly or Silver Hill Quarry, at the north end of the grounds of Huntington, some two miles west of Haddington. It belongs to the special group of quartz banakites, and most of the normal phenocrysts are of plagioclase ; but these are associated, in the large quarry, with sanidine crystals which are often two inches long, and in many cases conspicuously twinned according to the Carlsbad law. This rock is probably the finest example of a por- phyritic trachyte in the British Isles, yet so local is the development of these late-formed giant phenocrysts that at the west end of the. same quarry they have almost entirely disappeared. (c) The Fine Compact Trachytes, with the somewhat cheese-like fracture, are almost confined to the area extending for some distance south from Drem. They are generally decomposed and in the field resemble red or yellow felstones. In many of them small vesicles are common, even within the interior of the rock masses, and their general aspect is such as to lead us to suppose that they are lavas. In some small exposures, in the cutting west of Drem Station, the rock is somewhat porphyritic and shows the type characters very well. Fragments of an identical rock are abundant on both sides of the railway in the adjacent fields, but little is known of the rocks farther south till the rising ground about the Chesters is reached, where the compact trachytes cover a considerable area, extending to the crest of or even beyond Kilduff Hill. Farther south they seem to be replaced by trachyte more allied to the Skid Hill type, already described. Inclusions of Sediment in the Lavas. — In addition to the sedi- mentary material filling cracks in portions of the lavas, a consider- able number of fragments, mostly composed of marl, are sometimes found in the more viscous lavas. No such fragments have been noted in the more fluid basalts, but in the trachytes they are not uncommon, and in the mugearite at Lawhead, north of East Linton, they are abundant. In this case they must have been caught up near the surface, for they were moist, if not even wet at the time, each * Not shown in the one-inch map, but about 600 yds. north of Haddington Station. 80 Galciferous Sandstone Series. patch of marl having an empty cavity above it, obviously a steam dome, of considerable size. These patches of marl are very little altered, though intensely hardened, and even medium-sized clastic micas are unchanged. No fragments of intensely altered sediment, brought up from a great depth, have been noticed. G. B. Clastic Beds associated with the Trachytes. — Two small outcrops of sedimentary material occur almost at the crest of the Gar le ton Hills. They clearly belong to the same band and are composed of red marl mixed with a variable proportion of detrital igneous material, some of which is ash. The bed is best exposed in the western outcrop, where it is somewhat indurated and in microsections shows a centric structure, which strongly suggests the effect of heat and cannot have been produced by silicification. This bed is seen to overlie the felspar basalt (Markle type), a fact of special interest, as nowhere else has any such bed been seen between this basalt and the overlying trachyte. The trachytic tuff, so well exposed in the small burn joining the Tyne a little west of Nether Hailes, may be noticed next, as it occurs at a slightly higher horizon. Its upper portion has been hardened by an overlying trachyte, and has preserved its ash structure in a most perfect manner, as is revealed by the microscope. Of much greater importance is the band which, to the north-west of Haddington, occurs interbedded among the trachytic lavas, and which, if the inter- pretation given on the map be correct, persists farther to the south and east than the overlying trachytes, and thus constitutes for a considerable distance the local summit of the volcanic series. Eventu- ally it, too, dies out, and does not occur at all to the south of the Dunbar-Gifford fault. This interpretation is only one of two possible alternatives. The other is to suppose that the portion of the outcrop shown from the Tyne southwards belongs to a detrital rock similar in position to that which occurs on the Dirleton shore, and formed, like it, from the gradual wasting of the volcanic pile subsequent to the last surface manifestations of' igneous activity in the district. Ac- cording to this latter view the continuity of the outcrop shown on the map is somewhat deceptive, as it hides the fact that a little north of the Tyne the later detrital bed has overlapped on to an earlier breccia or tuff. It is easy to understand that such an overlap might exist and yet be very difficult to demonstrate. A bed of detrital material, to be described later, outcrops at the sharp bend of the Tyne immediately east of Haddington, and would, according to the second interpretation, be regarded as the continua- tion of the clastic rock seen farther east on both sides of the river. The most northerly exposure of the tuff intercalated among the trachytes is found in the small stream at Ballencrieff, near the railway. It is composed of more or less rounded fragments of trachyte, derived from different bands and mixed possibly with a little true ash. It contains little, if any, normal clastic material. A similar rock occurs again about a mile to the south-south-west, near West Garleton, as well as at two small quarries near Bangly Braehead. In a quarry west of Alderston Mains the greater part of the rock is trachyte, but the south-west face is composed of fragmentary igneous material mixed with a considerable proportion of marl. In the Dean, a little north of Haddington, we see a long exposure of these North Berwick and Garleton Area. 81 fragmental igneous rocks, with very little, if any, admixture of normal sedimentary material in the matrix, though small fragments of hardened marl may occasionally be detected mixed with the much larger ones of trachyte. No fragments of basic rocks could be found in it. Many of the trachyte fragments are coarse, and some contain felspars which approach in size those in the Bangly quartz banakite described on p. 79. Perhaps the bed has been partly formed by the washing down of scree material. A somewhat similar but much finer-grained bed is exposed in a large quarry near Amisfield Mains, to the east of Haddington. It has undergone a process of silicification, as have most of the detrital trachytic rocks, but in a specially marked degree. South of Amisfield Mains there are several exposures of the rock which has been mapped as the doubtful continuation of the bed just described. Good exposures occur along the course of the Tyne and its tributary, the Bearford Burn, but the best is found at the union of these two streams opposite the Mills. Basalt fragments are abundant in the coarse agglomerate, or conglomerate, here exposed, and this seems at first to favour the view that the bed now being described is a detrital bed formed from the denudation of the volcanic rocks, and lying uncomformably on various members of them. But a fact that has weighed with us in adopting the other interpretation, shown on the map, is that while compact solid blocks of trachyte are very abundant, the larger masses of basalt are extremely slaggy, and this suggests that the latter masses did not reach their present situation owing to the operations of erosion. Moreover, the fine grained tuff, which is seen in the Tyne section, faulted down against the coarser deposit, is indistinguishable in the field from the ash occurring in the glen to the east, whose true nature it has been found possible to verify with microscope. Farther south, near Caldale, gravelly layers occur along with the tuff. While we thus prefer to consider that this breccia belongs properly to the volcanic period and not to a later epoch of subaerial degradation, it must be admitted that we have not been able to come to an entirely satisfactory conclusion in the matter. G. b., e. b. b. III. BEDS ABOVE THE VOLCANIC SHEETS. In the coastal area the series of trachytic and basaltic lavas is succeeded by a thin group of beds composed largely of marl mixed with fragmental material derived from the underlying igneous rocks. The proportion of igneous fragments varies incessantly, and, in some places, beds, an inch or two thick, may be almost entirely composed of marl; while, at others, bands, several inches thick, may consist almost exclusively of igneous fragments, and might easily be mistaken for ash. Where fully developed these beds attain a thickness of about 50 ft., and it is a characteristic feature that in all but the highest band most of the fragments are small and more or less angular. The highest band, however, contains much larger fragments, and these are rounded, showing that there must have been a somewhat sudden change from conditions favouring sheet-flood erosion to those pro- ducing normal erosion. Above the band with rounded fragments comes a series of sediments of more normal character. 82 Calciferous Sandstone Series. These marly rocks, mixed with detrital igneous material, outcrop at the west end of Cowton Rocks in small detached patches firmly welded to the top of the felspar basalt, as if baked by it. This appear- ance of baking is, however, illusory ; the patches have been greatly hardened by silicification, but cannot have been baked, for they are not only younger than the felspar basalt but more recent than the trachyte, which so often overlies the basalt. A similar silicification of marly material associated with fragmental igneous rocks is a common feature of the volcanic area of East Lothian and indeed many other regions.* These more or less silicified beds are seen in considerable mass on the shore a little west of Cowton Rocks. They overlie the Cowton lavas and dip westwards under the higher beds in the small basin about Links House. A little inland they appear through the blown sand, and have been quarried for building the adjacent walls. They outcrop in a horseshoe form round the southern margin of the basin just referred to, and their highest band, containing well-rounded boulders, reappears on the north-east side of Yellow Craig Plantation. Some of these boulders are a foot in diameter, and all are greatly decom- posed. They consist of the felspar basalt and the trachyte seen on the shore close by, and are set in a matrix of comminuted frag- ments of the same material. A small patch of this conglomerate also occurs on the shore, a quarter of a mile north-west of Yellow Craig Plantation, and to the we^t of Longskelly Rocks. A little farther west, the lavas rise up in a low dome, but the fragmental rocks are again seen at Weak Law, and in this locality they rest on the trachyte, instead of the felspar basalt as at Cowton Rocks, so that they must be unconformable to the lavas beneath them. As before, small patches occur firmly welded on to the igneous rock, but at the foot of the cliff they form a solid mass at least 30 ft. thick, and are identical in character with the rocks at the west end of Cowton Scars. A sharp dip to the north-west soon brings down to the beach the highest band, which now consists of a yellow conglomerate containing both angular and well-rounded fragments, some composed of the felspar basalt and others of the Dirleton type of trachyte. A landward section of the fragmental material above the lavas is exposed in the railway cutting at the Spittal, but here its thickness does not seem great, and only a small proportion resembles the Weak Law beds. The bulk of it is a very fine pale rock, apparently composed of comminuted trachyte, which has been so hardened and silicified that its original character is difficult to make out. On the south side of the lavas to the west of Haddington nothing is known of the rock that lies on their immediate top, but at the sharp bend of the river, just east of the town, we see some very fine homogeneous material, having in part the mauve tint of a fine trachyte, and so compact that it might easily be mistaken for that rock. It has been proved to be finely comminuted trachytic material mixed with a considerable amount of clastic mica. This is probably the equivalent of the much paler material at the Spittal just referred to. * In the Carmarthen district Mr. Thomas has shown that in the tuffs and ag- glomerates associated with the Didymograptus murchisoni shales there are fragments of originally soft black shale that have been completely silicified and will now turn the edge of a knife. This result has been brought about without the help of igneous agencies, and the silica has been derived from the decomposition of felspar. H in North Berwick and Garleton Area. 83 Considerable light is thrown on the nature of the junction of the trachytes with the Lower Carboniferous sediments by a boring put down to the north-west of the smithy on the road nearly a mile east of Gladsmuir. This boring passed through a great mass of trachyte with no cover of normal sediments, though there may have been a small bed of trachytic detritus at the very top. Many years ago an earlier boring, which passed through a limestone of the Lower Lime- stone group, was put down near the site of the foregoing. By the aid of an adjacent well section and these two borings the outcrops under the drift were plotted, and it was found that the outcrop of the limestone was not broken by any large fault, and that a mass of trachyte must project almost to the base of the limestone. In great contrast to this, it is to be noted that a deep bore at Gullane, starting in beds certainly no higher than those at Gladsmuir, pierced more than 200 feet of sediments without reaching even the trachytic con- glomerate, already described, on the adjoining foreshore. The evidence of a local unconformity is thus very clear. For some distance west of Haddington, also, sedimentary rocks appear to have been banked against a sloping face of the trachytes, since in a small stream near Alderston, trachyte and sedimentary beds of a higher stratigraphical position than those at the bottom of the Gullane boring are seen close together, lying at gentle angles and without any appearance of a fault between. Most of those beds of the Oil-shale group which come above the conglomerate and detrital igneous rocks differ markedly from those previously described, and comprise sandstones and shales of normal Carboniferous types, with here and there a thin coal seam or carbonaceous smut. Portions of the lavas must, however, have remained above water for some time close by, and on somewhat rare occasions provided small rolled fragments to the later sandstones. In all probability they also supplied, during decomposition, the great quantity of dolomite and calcite that characterises the lowest sand- stones of the overlying series. In the coast district the most easterly outcrop of the higher rocks occurs in a little basin, the centre of which is near Links House. In the Eel Burn just south of the house a typical non-calcareous Carboni- ferous sandstone is exposed and no doubt occupies a slightly higher stratigraphical position than the calcareous standstones west of Weak Law. A note on the original field map states that a thin coal was found at the bottom of the well at Links House, and, in view of the steep dip often encountered along the margins of similar little basins in this district, it is quite possible that at the centre of the fold near the house there may be a considerable thickness of beds above the conglomerate. At Weak Law the conglomerate is overlain by a mass of dark shale with rows of impure ironstone nodules, lying in a well-defined basin which is truncated by a fault on its west side (Plate II.). West of the fault we find a typical calcareous or dolomitic soft cream-coloured sandstone ; and, close by, the top of another similar standstone, con- taining a thin band largely composed of small fragments of the lavas, too decomposed, however, for specific identification. Similar rocks continue to the headland formed by the basalt sheet ; but northwards the beds rise again and at low tide we see a greatly decomposed 84 Calciferous Sandstone Series. conglomeratic rock clearly belonging to the detrital group which, over- lies the lavas, for farther north again, in Eyebroughy Scar, even the underlying trachyte appears at the surface once more. Rounding the headland, some dark oil-shale crops out in Cheese Bay close to the southern margin of the basalt, and has yielded to Mr. Macconochie a suite of fossils, many in splendid preservation, which are dealt with in a separate appendix at the end of the volume. Further south the sandstones often show white specks which give a somewhat ashy aspect, but the specks are composed of calcareous matter, as is clearly proved when one of these beds is found in contact with a basic intrusion, when it shows patches of well crystallised calcite due to the aggregation of the material composing the specks. Lying in a small syncline above the third intrusion on the coast-line are some thin bands of fine-grained impure dolomite, which externally resembles hardened marl and has a peculiarly clean fracture. The top of the sandstone, south of the intrusion referred to, contains small highly decomposed fragments of the lavas, and little blocks of marl and sandstone identical in character with the rocks associated with the lavas. A thin band of sandstone a little further south also contains similar but much smaller fragments. At a locality close by (called Freshwater Haven on the six-inch map) a thin band of conglomerate is made up exclusively of small fragments of sedimentary material, few of which are appreciably rounded. They must be due to local erosion m the immediate neighbourhood. On the south-west side of Gullane Bay the beds consist of sandstones and shales with occasional coal smuts, and a good general idea of the nature of the rocks is gained from the journal of the boring at the west end of Gullane, given below in an abridged form. Journal of Bore put down at the West End of Gullane. Ft. in. Sand . 16 Fireclay and balls Sandstone and blaes 6 . 4 4 1 Fireclay White sandstone 2 2 4 7 Light fireclay Bastard limestone, hard 6 1 3 34 Blaes with sandstone rib 5 2 Light fireclay Sandstone with fireclay parting Alternations of blaes and sandstone . 13 . 9 . 13 6 1 6 Fireclay with sandstone bands Sandstone . 12 1 7 Brown blaes, carbonaceous 1 9 Alternations of fireclay and sandstone . White sandstone . 12 4 4 6 Blaes and fireclay Sandstone . 8 5 5 2 Grey blaes Sandstone 3 1 9 Blaes and sandstone plies . 2 6 Fireclay with sandstone ribs . . White sandstone . 15 5 5 6 Light blaes . 8 6 Carry forward . 162 U North Berwick and Garleton Area. 85 Ft. in. Brought forward . White sandstone, hard . 162 8 8 Grey fireclay and hard ribs Alternations of sandstone and fireclay Sandstone 7 . 11 . 14 6 3 6 Grey fireclay Sandstone 4 6 9 Dark blaes, carbonaceous ... 1 4 Sandstone . 3 Total depth . 214 04 Part of the above bore was enlarged into a well, and in the spoil heap abundant ostracods were found in both the carbonaceous and the calcareous shales. No pieces of the fossiliferous oil-shale already referred to were found either in this spoil heap, or in the cores, so that, unless this shale is of very limited extent, the beds which occur above the lava at Gullane cannot be much less than 300 ft. thick. At Gullane Point a part of one of the sandstones is crowded with struc- tures suggestive of worm casts, and at the base of this bed come the shales containing the ironstone nodules, that were once mined to a small extent, and gave the name of Ironstone Cove to this locality. Further south a few thin sandstones are seen near the Point, but, beyond this, the shore and adjacent ground are completely sand- covered, and nothing is known of the beds that intervene between these sandstones and the rocks immediately below the Aberlady Limestones. There are several sandstone quarries to the north-west of Gullane, and in one of these, the Whim Park Quarry, the following section is exposed : — Sandstone, slightly calcareous . . Marly shale Laminated hard shale Marly shale, base carbonaceous Carbonaceous shale Dirty coal Carbonaceous shale becoming marly Brown sandstone, variable Grey shale, carbonaceous at base Dirty coal Fireclay Sandstone, slightly calcareous . . Ft. in. . . 6 6 . 9 1 4 9 6 1 3 3 . 15 The lower coal smut continues on to the next quarry, and similar smuts are probably numerous in this group of beds, two having been previously noticed during the original survey, in Lairds Quarry, below Gullane Hill. Further inland, evidence has been gradually accumulated of the existence in Lower Carboniferous times of a narrow channel cut in a north-easterly direction through the trachytes near Dirleton. At the south end of the alluvium, south of Dirleton, sand- stone is seen in the stream, and a considerable amount of silicified marl is exposed at the junction of the four cross roads. Further to the south-west is a water-filled quarry in which a thin band of lime- stone was once worked, and still farther on, the arrangement of the 86 Calciferous Sandstone Series. columns in a basalt is such, as to suggest that it is a sill whose upper and lower surfaces are rigidly parallel, which one would not expect save in a sill that had been intruded between two sedimentary beds. g- b. Various Isolated Areas of Volcanic Eocks. To complete the volcanic history of the Garleton area, we have yet to describe its intrusive rocks ; but before doing so we may pause to notice certain restricted exposures of contemporaneous igneous rocks, occurring elsewhere throughout the county, which cannot in every case be referred strictly to the Garleton Hills platform. They all, however, belong to the same general period, and occupy various positions in the lower portion of the Calciferous Sandstone series. Four exposures will be dealt with, three of them occurring in the greatly faulted coastal area lying east of Dunbar, and the fourth far away to the west near Upper Keith. They will be described separately and in the following order : — 1. The Oldhamstocks and Fernylee Area. 2. Coast a mile east of Dunbar. 3. Railway cutting south of Broxmouth. 4. Upper Keith. 1. The Oldhamstocks and Fernylee Area. — In the burn west of Fernylee several lava flows are seen resting on an important mass of sandstone, while in the adjacent burn at Oldhamstocks ashes are exposed overlain by sandstones. Most of the ground between the two streams is obscured by drift, but it seems probable that the volcanic rocks of the two burns are parts of a single group, of which the lavas form the base and the ashes the summit. The north-eastern boundary of this little area appears to be a fault, nowhere clearly exposed, which throws down the igneous rocks against a comstone- bearing horizon some distance below the top of the Upper Old Red Sandstone. In the absence of fossils we are forced to rely upon somewhat indirect evidence in fixing the age of the volcanic rocks. Thus, since it is not possible to find a place for them in the coast section between Siccar Point and Skateraw, described in Chapters IV., VI., and XI., we must suppose they have been omitted from this section by the large fault, already referred to, which runs out to sea near Cove Harbour. This limits their occurrence to a position not less than 500 ft. above the base of the Cementstone group, and at the same time not as high as some of the Scremerston Coals. The important series of soft red, lilac and grey sandstones underlying the Fernylee lavas cannot, therefore, be of Upper Old Red Sandstone age, although they greatly resemble many portions of this formation. They amount to about 300 ft. in thickness, and it seems probable that they occur either as an intercalation in the Cementstone group or that they lie immediately above it, in the position of the Fell Sandstones of the North of England. In the latter case, the overlying volcanic rocks occupy a somewhat higher horizon than the basaltic group of the Garleton Hills, and it is noteworthy in this connection that the lavaform products of the two districts are distinguished by the almost Isolated Areas of Volcanic Rocks. 87 complete absence of phenocrysts among the basalts of the Oldham- stocks area. It is impossible to make a satisfactory estimate of the thickness of the volcanic series here, but it may amount to as much as 200 or 300 ft. A soft red and greenish sandstone, mixed with red and buff calcareous lumps, overlies the ashes. The section is not continuous, but this bed appears to pass in turn under yellow and grey sandstones and clay-shales which are exposed farther to the north- west, and which have yielded to Mr. Macconochie plant remains of Calciferous Sandstone age. 2. Coast a Mile East of Dunbar. — A narrow strip of igneous and sedimentary rocks belonging to the Cementstone group occurs in this locality, bounded by large faults on both sides, and lying between the Upper Old Ked Sandstone on the west and the Carboniferous Limestone series on the east ; two bands of vesicular lava crop out here and give rise to conspicuous scars on the shore ; in close associa- tion with these we find also some thin ashy bands which may indicate contemporaneous volcanic activity. The sediments with which these igneous rocks occur are to a large extent composed of greenish - grey shales, fine-grained white or yellow sandstones, together with courses and lenticles of cementstone and Indian red mudstone. Their strike is north and south, and they are either vertical or highly inclined towards the west. About 300 ft. of them occur on the west side of the lavas and dipping steeply over them, but it is tolerably certain they are in reversed order, as are the neighbouring beds belonging to the Upper Old Red Sandstone and the Carboniferous Limestone series on either side. We conclude, therefore, that the base of the lavas must be at least 300 ft. above the base of the Cementstone group. It is possible that it is much more, for we do not know how many beds have been cut out by the fault on the west. It may also be stated that near the base of the 300 ft. of sediments referred to there is a band of red poikilitic sandstone, with dolomitic matrix, which contains so many pieces of felspar as to suggest the presence of volcanic detritus. In about the same position, also, there is an exposure of a greatly decomposed igneous rock (10704) — perhaps a felspathic basalt — which may possibly be of contemporaneous character. The western or lower lava is in a very decomposed condition and contains many amygdules, some of which are as large as a hen's egg. The grain is fine and no porphyritic constituents can usually be dis- cerned. The sliced specimen (10707) shows that the rock bears a strong resemblance to the monchiquites ; this is an important point which will be further discussed in the petrological chapter. The upper or eastern lava is a basalt of Dunsapie type, and differs from the lower in containing conspicuous phenocrysts of plagioclase felspar and augite. Near high-water mark its thickness is probably about 100 ft., but in a northerly direction it becomes much less. The beds which succeed the upper lava are much obscured by seaweed and loose stones, but they appear to consist in the main of Indian red clay-shale with some thin ashy seams and a red sandstone. The ashy seams (10705) show distinct lapilli and but few quartz grains, but they are perhaps not much more than 10 ft. thick in all, and the highest seam observed is not more than 50 ft. above the lavas. 88 Calciferous Sandstone Series. 3. Railway Cutting South of Broxmouth. — In this cutting a nearly vertical band of purple volcanic ash, about 90 ft. thick, crops out with a north and south strike. Beds belonging to the Cementstone group dip steeply over it to the west, but are no doubt in inverted order, and after passing them we come, farther west, to a series of red sand- stones, which are referred to the Upper Old Red Sandstone. The thickness of the beds of the Cementstone group on the west side of the ash is about 300 ft. Some movement has taken place near their base, but it is improbable that more than a few feet of beds have been cut out by it. On the east side of the ash there is an obscure gap in which there is probably a fault with a considerable downthrow to the east. c. t. c. 4. The Upper Keith Area. — The only other exposure of an igneous rock of contemporaneous nature known in the county to which refer- ence has not already been made, occurs far to the west near Upper Keith. It consists of a thin ash bed made up of blocks of porphyritic basalt, and seems to be of considerably earlier date than any of those noticed above, since it is found in proximity to cornstones of Upper Old Red Sandstone age, which dip towards it at a gentle angle. E. b. B. CHAPTER IX. ASH NECKS AND INTRUSIONS CONNECTED WITH THE VOLCANIC EPISODE. Ash Necks. The Old Red Sandstone and Carboniferous rocks exposed along the Dunbar foreshore are pierced by more than 20 volcanic vents, varying in diameter from a few yards to over half a mile. The smaller ones are of course too small to be shown on the one-inch map, but SCALE OF FEET 250 500 750 FOOT n/t/OOE \ OIF OF STRATA + HORIZONTAL „ -^-ANTICLINAL r AXIS 1 DOLFftlTE DYKES Fig. i. — Map of Shore near Belhaven Point, west of Dunbar. their positions are indicated in Fig. 4. The material filling these vents is in most cases a sandy tuff, containing decomposing glass lapilli, blocks of amygdaloidal basalt and of the various types of sedi- ment belonging to the Old Red and Calciferous Sandstone series. This agglomerate is sometimes pierced by a plug of basic igneous rock. In one case only, that of the Dove Rock, situated 150 yds. west 90 Ash Necks and Intrusions. of Dunbar Castle, is the vent wholly filled by basalt, whilst a few of the small necks are filled merely with brecciated non-volcanic materials. In our detailed description of these necks it will be convenient to commence in Belhaven Bay and proceed eastwards. A patch of fine reddish or yellowish tuff containing pieces of agglomerate, tuff, indur- ated sandstone and shale occurs at the low-water edge of the beach just east of Belhaven Bay. Its boundary with the shales and cement- stones follows an irregular curving line and the junction is vertical or highly inclined. To the south of this neck and along the line of the dolerite dykes there are a number of small necks, measuring from two or three to 120 yds. in length, which are filled by a breccia of the local sediments. The blocks forming this breccia are angular and sometimes reach a length of 5 yds., in which case they may consist of several layers of shale and cementstone still adhering together. The surrounding strata may maintain their normal dip close to the edge of the vent, but often each bed as it approaches the margin is broken or bent and dips steeply inwards towards the vent. Some of these necks pierce the summit of low anticlines or domes which are overlapped by the succeeding beds, thus proving that the folds in these cases are contemporaneous with the deposition of the sediments. In one example, the overlapping beds seem to cover over one end of the neck, so that these small vents are perhaps contem- poraneous with the surrounding beds of the Cementstone series, and mark the first attempts in this district at the establishment of volcanic orifices by the explosive discharge of vapours. Four of the small necks are situated on lines of fault occupied by dolerite dykes of the type which elsewhere in the county cut the Coal measures, but in this locality it is merely possible to recognise that the dykes are all younger than the necks, though they do not always com- pletely traverse the latter, and in such cases may appear at first sight to be older. The main movements along the faults preceded the formation of the necks, but movements later than the intrusion of the dykes are not excluded. Some of the necks show no evident relation to fault or fold. The next vent to the eastward is that occupied by the mass of tuff which forms the line of high cliffs to the west of Dunbar. The ash is of a red colour, and on the whole is well stratified. It is made up for the most part of rapid alternations of gritty with finer bands which give the cliff a striped appearance. The matrix of the ash contains decomposing glass lapilli, but is so heavily stained by iron oxides that its original structure is obliterated. The mineral grains in the coarser bands are angular or rounded, the former predominating. They consist chiefly of quartz, which sometimes shows strain-shadows, plagioclase, orthoclase and microcline ; muscovite and biotite also occur in varying amount. Besides the glassy lapilli, small pieces of basalt and of quartzite are usually to be found. Embedded in the tuff are numerous angular, subangular and rounded fragments of vesicular basalt, and also of sandstone, cement- stone and shale. The stones are on the whole small, and are absent from certain parts, but here and there we see blocks of slaggy basalt measuring four feet across. Some of the blocks of vesicular basalt appear to be bombs. o a o 60 o 3 I'T « p to X 55 x ^ OS bs _§ _^ -^ § ■■* = "2 3 1 S- 5 1.2-5, o — a Q 2 "5 Ash Necks near Dunbar. 91 The dip of the tuff is at first at a high angle (50°-60°) to the east and south-east. It then wheels round at a lessened angle (30°-40°) to the north-east, and continues with this inclination close up to the eastern margin, where it becomes rather irregular, dipping sometimes towards, sometimes away from, the junction with the sediments. The tuff is traversed by some dykes of dolerite on the beach, while inland, on the eminence of Knockenhair, it is pierced by a plug of analcite basalt (Kidlaw type). The margins of this mass of tuff are very remarkable. As one approaches it from the west the gentle south- easterly dip of the sandstones, shales and cementstones increases to an angle of 50° and upwards, and then the beds are abruptly succeeded by the tuff. As we trace the rocks north-eastward the higher group of cementstones and shales (see inset map on a previous page) is cut out and the sandstone is truncated against the tuff. The junction is some- times obscure, and although some parts of the tuff are very quartzose, there does not appear to be any intercalation of tuff in the sedimentary series. Running through the tuff, at a distance varying from 15 to 50 yds. from its margin, is a conspicuous sandstone dyke, which varies in width from a few inches to several feet. It behaves like a dyke of igneous rock, running sometimes with the bedding of the tuff, sometimes abruptly truncating it. In composition, however, it is a sandstone, and consists of closely packed angular bits of quartz with a small admixture of felspar grains and scales of white and dark mica. There is very little " paste " between the grains, but what is present is micaceous. Other sandstone dykes occur here and there throughout the ash.* The eastern boundary of the tuff is a very irregular line. The sandstones, which a few yards away from the tuff dip towards the south-east, are bent down against the volcanic rock, which is likewise jammed into their crevices. And not only are they thus depressed, but as they approach the tuff their bedding becomes less distinct, and they are hardened and affected by numerous little faults. A small ash neck situated on a line of fault is exposed in the ladies' bathing-place. About 150 yds. west of the Castle an oh vine analcite basalt, forming a conical knob called the Dove Rock (Plate III.), has been intruded into the Upper Old Red Sandstones. The sand- stones generally dip at gentle angles to the E.S.E., but round the Dove Rock they are broken and bent down, in the same manner as they are depressed round the ash necks. The indura- tion of the sandstone is, however, more marked in the case of the Dove Rock. The Castle Rocks mark the site of another vent, now filled with red and green tuff. It is almost entirely surrounded by the sea, so that the nature of the junction with the sediments is doubtful. The green tuff is simply that part of the tuff which has escaped staining by ferriferous solutions. It consists of fragments of basalt and de- composing basaltic glass, with grains of quartz, striped and unstriped felspar and mica. The tuff, as well as the cornstone-bearing rocks * In a neck at East Grange, six miles west of Dunfermline, Dr. B. N. Poach has noticed vertical rents filled with sandstone. Their origin is ascribed to the successive subsidences which occurred during the settling down of the materials washed into the vent. See Sir Archibald Geikie's " Ancient Volcanoes of Great Britain," 1897, vol. i. p. 426. 92 Ash Necks and Intrusions. to the west of the Victoria Harbour,* is pierced and indurated by the irregular dyke-like mass of olivine analcite basalt, on which the Castle stands (Plate III.). The Old Harbour, together with the lower part of the town adjacent to it, is situated on another neck filled with stratified red tuff, or tuff in red and green bands. The margin of the neck is exposed on the shore below the harbour bulwark. The sandstones dip at low angles away from the neck towards the south-east, but as each bed approaches the edge of the neck, it bends over and dips down at a high angle towards the tuff, the margin of which is sharply defined, and strikes across the beach in a north-easterly direction. Before reaching low tide mark, however, the edge of the neck curves round toward the west, and passes under the harbour wall, but the inward dip of the strata follows closely the margin of tuff. The columnar basalt situ- ated between the Victoria Harbour and the Broad Haven is an inclined sill, intruded into the tuff of this neck. Toward the south-east the sandstones are again interrupted by a mass of red tuff, which is best exposed below the Coastguard Station. In some places it is coarse, wholly unstratified, and contains frag- ments of vesicular basalt, cementstone, sandstone and tuff. In other places it becomes finer, contains few or no stones, and shows vertical or highly inclined bedding. The junction of the tuff with the sand- stones is well seen on its southern edge. The sandstones, which a little distance off are striking at the tuff, become indurated on ap- proaching it, and are bent towards it at angles of 60° or more. At the lower part of the beach the sandstones are broken off at the apex of the bend, and the severed portions He vertically between the tuff and the normally dipping sandstones. Near the low-tide mark the margin of the tuff turns towards the north, and some evidence that the tuff is bounded in a manner similar to that described above may be obtained along the northern edge of the patch of boulder-strewn beach which interrupts the section. A few yards farther south-east the sandstones are again inter- rupted by tuff, a coarse reddish-coloured mass of tumultuously mingled fragments, sometimes three feet long, consisting for the most part of yellow, green and red sandstone and cementstone, imbedded in a dull red sandy paste. This tuff comes through the yellowish and reddish sandstones and marls exactly like a dyke. The strata cut through dip E. 10° N. at angles varying from 15° to 20°, and the tuff forms a curving band varying in breadth from six or seven yards at the upper part of the beach, to 16 yds. just before it ends off near low-water mark. Below its termination a remarkable hole, the cross-section of which measures six feet by four feet, has been drilled vertically through the sandstones, and is occupied by pinkish and greenish tuff containing fragments of sandstone, shale and decom- posed lapilli. Writing of the dyke-like mass of ash mentioned above, Sir Archibald Geikie says f — " If the rock were greenstone it would occasion no difficulty, for it would be set down at once as a trap-dyke. But when in place of * The Victoria Harbour lies just east of the Castle. The Old Harbour lies 100 yds. south-east of the Victoria Harbour, and the Broad Haven comes between the two. Neither the harbours nor the haven are named on the one-inch map. t See " Geology of East Lothian," Mem. Oeol. Survey, 1866, p. 44. Ash Necks near Dunbar. 93 a lava-form rock, which would rise in a melted state, and solidify in a fissure, we meet with a fissure filled with a coarse volcanic con- glomerate, the explanation of the phenomenon is not so simple. The boundary lines between the ash and the sandstones on either side are sharp, sinuous and steep, or vertical. I do not think they can be explained as lines of fault. Moreover, there is a tendency in the stones of the ash to arrange themselves with their long axes parallel to the sides of the ' dyke.' The mass is not stratified, but there seems to be some relation between the arrangement of its larger flatter stones and the direction of its sides. Fragments of the same kind of sandstones which bound the ash occur here and there abund- antly in it." The sandstones and marls resume their place on the beach, and continue to dip in an easterly direction at angles ranging from 15° to Fig. 5. — Eye-sketch (Ground- plan) of Neck of Ash in Calciferous Sandstone. Beach east of Dunbar. After Sir A. Geikie. 25°. Below York Lodge they are invaded by another mass of ash and as this is the last and most interesting of the sections, showing the relation of the ash to the stratified rocks, it deserves a more de- tailed description, which has already been given by Sir A. Geikie.* " The above rough sketch (Fig. 5) represents a ground-plan of the beach at this point. It was drawn merely by the eye, and makes no pretensions to accuracy of proportion, but it will be found, I think, to represent correctly the main geological features there exposed. " As the sandstones approach within 15 or 20 ft. of the ash, they begin to show traces of alteration. The bedding becomes less distinct, the jointing more abundant, and the rock weathers with a singularly rough carious surface, very unlike the aspect of the same beds away from the ash. This zone of rough sandstone reefs encirc- ling the ash can be detected from some distance. Within a space of two or three yards from the edge of the ash the bedding of the sandstone is in some parts wholly obliterated, while in other places * " Geology of East Lothian,'' p. 45. 94 Ash Necks and Intrusions. it can be traced in a vertical and broken position. The sandstones are then much hardened. At several points they are prolonged into the ash in narrow tongues, like veins of igneous rock, and these prolongations consist of a hard red or speckled fine-grained sand- stone. " As shown in the ground plan (Fig. 5), these stratified beds are perforated by a rudely semicircular mass of ash, the boundary line being irregular, curving, and for the most part vertical. If this ash were a coarse, unstratined agglomerate it would naturally be regarded as volcanic material filling up an ancient orifice. But, strange to say, it is on the whole well stratified, sometimes full of thin seams of red sandstone, the dip being toward the west, always at a high angle, and sometimes vertical. At the south-east side the texture is much finer than on the opposite side, where stones, often very angular, and sometimes, but rarely, several feet in diameter, are more abundant. In general character the ash is a fine-grained, sandy, f elspathic, stratified rock of a dull purple or grey colour, mottled with white f elspathic lapilli." Immediately beyond this section the beach is traversed by the important fault which has already been referred to as the Dunbar - Gifford fault. At extreme low-water mark, about 100 yds. east of the fault, a small neck of red tuff contains pieces of cementstone, shale and sandstone, the last-named in blocks two feet long. h. b. m. About a mile south-east of Dunbar Harbour, and 60 yds. west of the two bands of lava described in Chap. VIII., another neck is exposed within the Cementstone group. It is about 100 yds. long from north to south and 30 or 40 broad, and contains considerable masses, as much as seven or eight yards long, of red and white sand- stone and of cementstone, all jumbled together in a most irregular manner. These masses are embedded in a soft, purplish, somewhat ashy rock, and some of them, and parts also of the sandstone at the sides of the area, seem altered and hardened. c. t. c. Inland a mass of unstratined red tuff is exposed at the eastern end of the grounds of Biel. Though the junction is nowhere exposed, the surrounding strata appear to be truncated by the tuff, which is probably filling a vent. The occurrence of blocks of cementstone and Carboniferous sand- stone in the necks, which pierce the Upper Old Red Sandstone, proves that some part at least of the material which now occupies the vents fell or was washed in from above, and it is probable that the strati- fication of the tuff was brought about during this process. Whilst these masses of tuff are certainly not interstratified with any sedimentary series, their lithological similarity to the tuff under- lying the Garleton Hill Volcanic series and their geographical position between the Garleton Hills and the detached volcanic areas of Calci- ferous Sandstone age near Broxmouth and near Oldhamstocks, com- pels the belief that they are of Calciferous Sandstone age. The minor vents, indeed, afford evidence that volcanic activity had com- menced whilst the Cementstone beds of Belhaven were being deposited. Further, the absence of fragments of Carboniferous Limestone from the tuffs of the major vents is another indication of their Calciferous Sandstone age, while the fact that trachytic rocks are unrepresented renders it probable that none of the vents are as young as the later Stocks. 95 part of the Garleton Hill volcanic episode. It must be pointed out, however, that the plugs intruded into the Dunbar necks have the same petrographical characters as those intrusions which in the Garleton Hills succeeded the close of surface volcanic activity. It may be supposed either that the plugs at Dunbar were much later in date than the necks, and contemporaneous with the later intrusions of the Garleton Hills, or that they were closely connected with the activity of the necks, and that the petrographical type which they represent appeared earlier in the outlying Dunbar district than in the Garleton Hills. In favour of the latter view there is the strong probability that the analcite basalt in the Cementstone beds about a mile east of Dunbar is a lava-flow. To a still later date again belong the dolerite dykes to which refer- ence has been made, and it is interesting to note that they too have been influenced in their mode of occurrence by the pre-existence of the vertical ash necks. This point will be referred to more fully in Chapter XIV. h. b. m. Inland other small necks have been mapped, which cannot be established with the same certainty as those exposed in the shore sections. One occurring just north of Traprain Law contains, in addition to ash, highly porphyritic basaltic intrusions of the same type as the lavas immediately to the north. The Morham Church neck, between Haddington and Garvald, is distinguished by being occupied by trachytic agglomerate. A small orifice filled with basic tuff occurs also to the south, near Kidlaw, piercing beds of Upper Old Red Sandstone age. e. b. b. Stocks, Laccolites and Sills connected with the Volcanic Episode. One of the most striking and best-known features of the East Lothian volcanic district is the presence of certain stocks, forming conspicuous landmarks, which are composed of igneous material that once welled up through huge pipes or ducts, where finally it consolidated. The number of stocks revealed by the processes of denudation is considerable, and it is clear there must be many more not similarly dissected. The stocks are essentially round or oval in cross section, and, as might be supposed, vary greatly in size. We shall attempt to follow a rough chronological sequence in the descrip- tions, first describing basaltic intrusions of a similar type to the lavas, then mugearite intrusions, then trachytes, and lastly, a great suite of basic sills and stocks, which seem to have followed the extinction of surface activity in East Lothian. THE EARLY BASIC INTRUSIONS. St. Baldred's Cradle, a little north of Tyne Mouth, is the largest of the early basic stocks and the finest of all for the purpose of field, study. It is formed of an oval mass of reddish-grey mottled rock, the margins of which, through three-quarters of the circumference, correspond almost exactly with high-water mark. Exceptional facilities are thus afforded for examining the nature 96 Ash Necks and Intrusions. of the surrounding rocks and the effects produced on them by the intrusion. These rocks are clearly sediments deposited in water, and close to the stock are greatly indurated, but considering the size of the intrusion and its basic nature the amount of metamorphism seems singularly small, and extends only a few yards from the margin. The most noticeable point, however, is the great dragging down of the sediments that accompanied the shrinkage of the stock on cooling after consolidation. As the latter is approached, the beds on all sides show a gradually increasing dip toward the stock, which at the margin amounts to at least 40° ; as this dragging down is a measure of the contraction of the plug during cooling, it is obvious that the depth to the original reservoir of igneous material must be enormous. The rock is a rather coarsely crystalline basalt or dolerite of the Craiglockhart type, and has, when fresh, a somewhat mottled aspect, due to the presence of large crystals of augite ; when the rock is decomposed the mottling is still more marked, owing to the further presence of numbers of small red spots, due to olivine, showing the iddingsite type of decomposition, so characteristic of the basaltic lavas. The composition and field characters of the intrusion show that it was almost certainly one of the pipes that fed the basal lavas, characterised by large augites, such as occur in the Whitekirk area, though there is a certain difference in structure between it and them owing to their consolidation at the surface. A similar rock with large augites (10833) occurs in the inner cliff west of Seacliff House, and is divided into two parts along a line, which does not appear to be a fault. It is associated with a red false- bedded sandstone which seems at one point to be banked against an eroded edge of the igneous rock ; the latter contains numerous small fragments of similar sandstone, but these, perhaps, represent inclusions caught up by an intrusion rather than deposits in cracks in a lava. In addition, little cavities filled with calcite and quartz are very abundant at this edge. In the face of the inland cliff there is a small cave, the base of which is cut in the underlying sediments. A number of fragments of sedimentary material occur in the lower part of the igneous rock, in such a manner as to suggest that they were wet when the molten material flowed over them, and caused a sudden develop- ment of steam, sufficient to blow them as fragments into the molten rock. Their size and angular form seem to preclude the idea of their being part of the land surface, and it seems as if the igneous rock had been intruded at a sufficient depth for the sedimentary material to have had considerable coherence. The rock itself (10833) contains large augites and externally recalls the basal sheets of basaltic lava in the Whitekirk area. At the extreme end of the Car are some very small patches of basalt on one of which the Beacon stands. They are composed of similar material to the igneous rock last described, and may once have been continuous with it, but we do not feel certain whether they represent minute patches of some of the earlier lavas or of an intrusive sill. G. B. Mention has already been made of the lavaform intrusions in the small neck north of Traprain Law. To the west of the Law a pro- minent little stock also occurs which is composed of a dolerite related Stocks and Laccolites. 97 to the Dunsapie type, but markedly ophitic. Much farther to the south-east, near Saughland, there is another basaltic outcrop which shows no clear field relations but is intermediate in petrological character between the Craiglockhart and Dunsapie basalts. Prob- ably also the intrusions at Dunbar, on the east side of the Victoria Harbour, should be referred to this category of early basic intrusions, although they are too decomposed for accurate deter- mination. E. B. B. MUGEARITE. A mugearite intrusion occurs on the shore at Frances Craig, a mile north-west of Tyne Mouth, but possesses no special interest. TRACHYTIC STOCKS AND LACCOLITES. North Berwick Law. — The most accessible of the trachytic stocks forms the bold and completely isolated hill of North Berwick Law, which projects to a height of more than 400 ft. above the general level of the surrounding country and is probably the most striking scenic feature of East Lothian. The rocks penetrated by the intrusion are completely concealed by drift except near the south-west foot of the hill, and even these are too far removed to allow us to discern the effects of the intrusion on the sur- rounding sediments. The rock exposed in the quarries on the south side of the hill is of a rich red brown colour, which is mainly due to the decomposition of the ferro-magnesian silicate ; the felspars are, however, still fresh enough to impart a faint sugary aspect to the rock if it be closely examined. The brown tint, though not so pronounced as in the quarries, is also well marked on the eastern or unglaciated side of the hill, and, in addition, at the crest on this side a well-marked vertical fissile structure is present and suggests the proximity of the original edge of the intrusion. On the western side, which has suffered con- siderable glacial erosion, the browner and more decomposed part has been removed and in places the rock is sufficiently fresh to show its affinities to that of Traprain Law. Further confirmation of this resemblance is provided by the microscopic characters of a few blocks of much finer material which are strewn on the south shoulder of the Law and evidently derived from the hill, although carried up by ice from the western outer margin into their present position. The Bass Rock. — Of the numerous isolated rock masses that project above the sea in the North Berwick area by far the most picturesque is the Bass Rock (see frontispiece) which rises with steep and often precipitous sides to a height of 350 ft. above sea-level and descends sheer down 60 ft. below it. The rock has been visited by several geologists, among others by Mr. Goodchild, who supplied the specimen examined and described by Dr. Hatch. This specimen was taken from the brown decomposed surface material and so seemed different to the rock of Traprain Law, but, fortunately, when a deep hole was made for the foundations of the new Lighthouse some of the material extracted was brought ashore as ballast and several pieces were 7 98 Ash Necks and Intrusions. secured. These show that the fresh rock is a phonolitic trachyte differing from that of Traprain chiefly in its non - porphyritic character. G - B - The Traprain Law Laccolite. — A glance at the map shows that Traprain Law lies in the heart of a dome and is completely surrounded by sediments of the Cementstone group, while the latter are in turn all but encircled by the outcrop of the overlying bedded igneous rocks. There are numerous exposures in the neighbourhood of the Law, and Mr. Howell showed long ago in bis mapping that the strata are always steeply inclined away from the hill — a phenomenon which has ever since been regarded as directly due to the intrusion of the phonolite.* The recent re-mapping of the mass has fully confirmed this relation, and has provided evidence also, that the dome shape of the Law is that of the original intrusion, and that little more has been done by erosion than to remove the covering of tilted sediments beneath which the viscid molten mass consolidated. In fact, the rounded outline of the Law has been determined by a series of platy joints which arch over the top f and sweep round either end of the hill, and which are regarded, for the following reasons, as cooling joints developed parallel to the original surface of the intrusion : — 1. The platy structure is not due to fluxion of the magma, since a well-developed and often sharply convoluted flow structure is also exhibited, which is cut by the more even platy jointing, though as a rule the two structures run nearly parallel to one another. 2. Upon the south-eastern side of the hill the sediments creep half- way up the slope and rest in this position with a dip of 50°, conforming with the inclination shown by the platy structure of the phonolite in the neighbouring exposures. 3. In the great quarry excavated in the northern face the laminae formed by the platy joints are thin near the exterior, while toward the centre of the mass they become gradually thicker, and, con- currently, the rock assumes an increasingly coarse crystalline texture. Unfortunately there is little evidence regarding the base of the intrusion, although at one place, the western front, deeply eroded by glacial action, shows a vertical blocky columnar jointing, which suggests that the igneous rock may possess a more or less horizontal floor at no great distance below the present surface. The evidence then, though incomplete, favours the interpretation that Traprain Law is an exceptionally perfect example of the regular type of laccolite such as has been described by G. K. Gilbert. J A similar rock forming the Hairy Craig sill, immediately to the north of the Law, has also tilted the overlying strata of the Cement- stone group, and must therefore be an intrusive rock, though it is frequently very slaggy — a peculiarity which is probably due to its position on the flanks of the Traprain Law laccolite, for Gilbert has pointed out § that the outer limit of flexure of the strata surrounding a laccolite marks a zone particularly prone to sill intrusion, no * See, for instance, Sir A. Geikie's " Ancient Volcanoes of Great Britain," 1897, vol. i. fig. 132, p. 403. f This feature is shown in a photograph by Mr. Lunn reproduced by Sir A. Geikie, " Ancient Volcanoes of Great Britain," 1897, vol. i. fig. 133, p. 404. % " Report on the Geology of the Henry Mountains," U.S. Oeogr. and Geol. Survey, 1877. § Op. cit., p. 20. Stocks and Laccolites. 99 doubt owing to relief of pressure in this position. The Hairy Craig sill was therefore very likely intruded from the same reservoir as Traprain, but under such diminished pressure as to allow of local frothing in the magma and the consequent formation of slag. The petrographical characters of the Traprain Law trachyte link it with the Garleton Hill volcanic episode, and suggest that it belongs to a late phase of the same, and this supposition is greatly strengthened by the field evidence which shows that this intrusion has tilted the surrounding basaltic lavas, and has also, apparently, deflected the strike of the overlying trachytic flows. E. B. B. Pencraig and Garvald Laccolites. — The intrusive character of the large boss-like sill or laccolite of fine-grained trachyte, which occurs north of the road between Haddington and Bast Linton, is best shown by the manner in which its eastern margin crosses the outcrops of the lavas. When fresh it is almost identical in char- acter with the non-porphyritic trachytes already described in con- nection with the lavas, and has a similar sugary fracture, but oval structures are not often developed in the weathered rock. The finest exposure occurs in Pencraig Quarry, on the East Linton Road a little north-east of Over Hailes. The northern margin is very ill defined. g. b. -The Garvald laccolite, three or four miles farther south, is also a large mass of non-porphyritic trachyte. It is so deeply dissected by erosion that the form of its upper surface is doubtful, but the base is flat and has been entirely cut through in one place by the Papana Water. e. b. b. BASIC SILLS AND STOCKS CONNECTED WITH THE VOLCANIC CENTRE, BUT LATER THAN THE FINAL SURFACE MANIFESTATIONS. In East Lothian several sheets and stocks of basic igneous rock occur at various horizons below the Aberlady limestones, and one similar intrusion also penetrates these limestones. These intrusions may be divided into two main types easily dis- tinguished in the field ; the first is fine grained and includes the monchiquites and analcite basalts ; the second is coarser and includes the teschenite group. The former and more common type is a compact dark heavy rock often possessing a well-marked columnar structure ; the freshly broken specimen shows in most cases a few small sub-lustrous spots, rather less than a pea in diameter, which are of almost invariable form, no matter in what direction the rock is broken, and which have been proved in certain cases to be crystals of analcite. A perfect example of one of these analcite basalts occurs on the coast opposite Eyebroughy Scar, while others constitute the islands of Fidra and the Lamb. The sills appear to be fed by a large number of independent stocks, as may be seen on the cliff top above the Gegan, some three miles east of North Berwick ; the cliffs show that in addition to the principal stock, or main feeder, there are round about it, at varying distances, numerous small dyke-veins, the whole reminding one of a spider and its legs. 100 Ash Necks and Intrusions. Stocks of this age are more numerous than those connected with the supply of lava streams, and vary in diameter from a hundred to less than ten yards. Of the smaller examples the Yellow Craig, on the shore at the east end of North Berwick, possesses most points of interest. It is some- what irregular in shape, being about 30 yds. broad and tapering to one end. At the shore end it is in contact with red marls that strike obliquely at it, and show a small dragging down at the junction, similar to that described above in connection with St. Baldreds stock. On the south-east margin, bits of these marls are caught up in the intrusion, and farther seaward blocks from the ash are also caught up. At the north-east end the small mass has been intruded into the agglomerate beds of the green ash, and owing to the great variation in size of the boulders in this agglomerate, and the greasy nature of the matrix in which they are embedded, the molten material as it opened the pipe up which it travelled has forced these blocks to arrange themselves with their long axes parallel to the margins of the duct, so as to give more relief to the pressure, and this has pro- duced the impression that the agglomerate has tumbled into a neck. Similar phenomena are frequently seen near faults in the ashy con- glomerates of Old Bed Sandstone age ; the stress of the fault causing the boulders to turn round in the greasy matrix and to arrange them- selves parallel to the fault plane ; if, however, the matrix of the conglomerate is of a sandy nature, having a strong " bite " or grip, the boulders no longer turn round near a master fault, but are thrown by a series of step faults. Another stock of similar material, in Yellow Craig Plantation, about two miles west of North Berwick, passes through a mass of decomposed conglomerate made up almost exclusively of fragments of the adjacent felspar basalt and trachyte. Similar small stocks occur to the north-west of Dirleton ; and it is clear that the number of intrusions of this type is very large — which may be correlated with the fact that the individual sills supplied by this type of stock are never continued far. G. B. The Castle Bock (Plate II.) and Knockenhair stocks, intruded into the ash necks of Dunbar, possibly also belong to this last phase of activity ; many others occur, but we need only mention here the important intrusion of Fernylee near Oldhamstocks, the well-known Chesters Quarry sill, its companion the Limplum sill, between Garvald and GifEord, and farther west still the Kidlaw sill. All the above- named show intrusive characters in the field, and as their microscopic characters unite them into a single group it seems probable that they are of the same age as the Dirleton sills, and later than the last outpouring of lava in this district. Difficulties in the way of accepting this generalisation are discussed in the petrographical chapter. The second and more coarsely crystalline type of later sill, mark- ing the close of the volcanic episode, includes the teschenites. There are several intrusions of this character in the sediments above the volcanic zone between Gosford Bay and Aberlady, and others at lower stratigraphical levels ; the evidence of the age of the latter cannot be regarded as conclusive. E. b. b. The sill in the highest stratigraphical position in the county is Intrusive Sills. 101 the Gosford Bay analcite dolerite, which is interstratified with beds of the Lower Limestone group, and has been folded along with the latter into a gentle syncline. Its intrusive nature can be proved from its transgressive relations and the alteration effected on the sediments, both above and below, the sandstones being changed into quartzite and the limestones to marble. Where it comes in contact with black shales it is itself altered to white trap. Some small exposures of the dolerite and squirts of white trap are also seen on the shore near Aberlady, but the sections are much obscured by sand. In the section north of Dalskelly Craigs there is a circular area, about 150 yds. in diameter, in which the strata dip away from the centre in all directions. This area is permeated with white trap, and the rocks are much altered, a thin limestone being changed to marble. c. b. c. Two important teschenite sills occur at Gullane above the lava group, and a similar rock constitutes the intrusion at Point Garry, North Berwick. A fine-grained essexite or essexite-dolerite forms the island of Craigleith, as will be seen in the petrological chapter, while an olivine analcite dolerite, closely allied to the teschenites, occurs in two plugs at Bathan's Strand, south of Frances Craig, near Tyne Mouth. e. b. b. The most interesting outcrop of the Gullane teschenite sills, already mentioned, on the coast, is that which occurs on the east side of the Hummel Rocks. The top of this sheet is much decomposed, but the overlying rocks are so indurated that we are almost compelled to suppose it to be intrusive, though it shows a phenomenon, described in the next paragraph, that is difficult to explain on this supposition. Sedimentary Dykes. The igneous rock on the east side of the Hummel Rocks is traversed by a number of small straight ridges or wrinkles that on inspection prove to be small sedimentary dykes composed of fine sandy marl. At the top of the igneous rock these dykes are hardly broader than a penny piece, but they rapidly broaden downwards, and often attain ultimately a breadth of six inches. The infilling material is usually hard, but it is uncertain whether this is due to the fact that the igneous rock was still hot when the marl filtered in, or whether there has been a subsequent hardening due to silicification. Nowhere have these curious dykes been found in such abundance as at the Hummel, but they occur at many other localities also, as in the trachyte of Weak Law, where, again, the cracks are narrowest at the top, and are evidently contraction cracks developed on cooling, the fine top having contracted far less than the rather coarser interior. Somewhat similar but rather smaller dykes occur in the green ash, and probably owe their origin to contraction on heating and drying, as is suggested by one special dyke that is the largest of the whole series. This occurs on the scars on the north side of the small stock of the Yellow Craig, at the east side of North Berwick. The intrusion has clearly heated and dried the adjacent incoherent ash, and has thus caused a long crack to open, as much as a foot broad in places, which is 102 Ash Necks and Intrusions. now filled with, a very hard sandy marl. The adjacent material being green ash, it is clear that the marl must have filtered down from a considerable height above. The material filling the stock is known to have been intruded later than all the local lavas, so that at the time this crack was opened there must have been a cover of at least several hundred feet of rock above the point where the dyke is now seen on the shore ; indeed the cover may, possibly, have amounted to as much as a thousand feet. It is worth noting that in many cases these little sedimentary dykes show a fairly well-marked and approxi- mately horizontal bedding. G. b. CHAPTER X. PETROLOGY OF THE VOLCANIC ROCKS AND ASSOCIATED INTRUSIONS. Introduction. Sir Archibald Geikie in his general paper on the volcanic rocks of the Forth Basin* described several types which occur in East Lothian, but Dr. F. H. Hatchf was the first to devote a special memoir to the petrology of this district. His paper owes much of its value to the numerous chemical analyses which accompany it, and which were contributed by several workers — J. S. Grant- Wilson, J. H. Player, G. Barrow, and A. Dick, jun. He clearly described most of the principal igneous rocks belonging to this volcanic centre, while especial import- ance has been universally attached to two of his determinations. Thus his detection of a phonolite (Traprain Law) of Carboniferous age disposed of the contention that this group must be regarded as peculiarly the product of Tertiary and Post-Tertiary eruptions, while his description of the " limburgite " of Chesters Quarry, Whitelaw Hill, has made this rock familiar to petrographers in all parts of the world. But the value of his work would be misrepresented by a citation of particular instances. He took as his subject a volcanic district situated in Scotland whose eruptions date back to the earlier portion of the Carboniferous period, and demonstrated for it an association of igneous products such as characterises the various modern volcanic centres which belong to what are termed the alkali petrological provinces. Representatives of the more extreme types occurring elsewhere are, however, absent from East Lothian, and the district, as might be expected, possesses certain special characteristics of its own. Among these may be noticed the complete absence of leucite, both in basalts and trachytes (but possibly represented in a kulaite), the prevalence of aegirine-augite as the ferromagnesian element of the trachytes and the occurrence of mugearites ; but such peculiarities are no more important than those which distinguish one volcanic district from another at the present day. The support which evidence such as this affords to the theory of magmatic differ- entiation is so obvious that it need not be dwelt upon. Furthermore, it has been found possible to adequately describe the great variety of igneous rocks occurring in East Lothian without the invention of a single new name, a fact which clearly shows that modern petrological nomenclature must be based upon a more or less sound foundation. Another interesting point which may here be noticed is the fact that * " On the Carboniferous Volcanic Rocks of the Basin of the Firth of Forth — their Structure in the Field and under the Microscope," Trans. Roy. Soc. Edin., 1880 vol. xxix. pp. 437-518, plates ix.-xii. f " The Lower Carboniferous Volcanic Rocks of East Lothian," 1892, Trans. Roy. Soc. Edin., vol. xxxvii. pp. 115-126, plates i. and ii. 104 Petrology. the type of petrological province to which a particular district belongs is evidently not a constant function of its geographical situation, but may vary immensely from one geological period to another. Thus the Central Valley of Scotland, during Lower Carboniferous times, formed a portion of a province markedly in contrast to that in which it was included during Lower Old Eed Sandstone times. Since Dr. Hatch's paper no general review has been made of the petrology of the district until the present revision. Prof. B. R. Young,* however, has described an interesting example of an " olivine analcite diabase " or teschenite from the lower Gullane Head sill, and also noticed the occurrence of olivine nodules in the upper Gullane Head sill. The present petrographical revision has been conducted under the general supervision of Dr. Flett, who has assisted me in every possible manner, while Dr. Pollard and Mr. Radley have each furnished two new and complete analyses which are especially welcome. Several additional points of interest have been ascertained in the course of the enquiry. In many cases these have been already referred to in the three preceding chapters, since they are intimately connected with our increased knowledge of the field relations of the various groups. The most important points are as follows : — (1) No andesites are known, for all the intermediate lavaform rocks belong rather to the trachydolerites. Mugearites are well represented together with at least one kulaite ; they may occur intercalated at any horizon in the lower or basaltic portion of the volcanic group, and in certain cases are considered to be true super- ficial flows. In like manner, the intrusive mass of Craigleith Island, North Berwick, is shown to be an essexite, or essexite-dolerite, almost identical with those described by Hibsch from Bohemia. Quartz banakites have also been recognised, but they are linked more closely with the trachytes. (2) A singularly uniform upward succession, from more basic to more acid, can be made out among the basaltic lavas. (3) Prof. B. R. Young's record of olivine nodules has been con- firmed, and their occurrence in additional localities ascertained. (4) Subsequent to the outpouring of the trachytes, a series of very basic intrusions, mostly in the form of sills, invaded the district. These later basic rocks are of closely similar type to certain among the lavas of Burntisland and Bathgate, and furnish a valuable link helping to unite the histories of the various Carboniferous volcanic centres into one continuous whole. (5) In the groundmass of most of these later intrusions, analcite plays an important role ; some of them are teschenites, and some monchiquites, according to Pirrson's f interpretation of the latter group, and in this connection it has been found necessary to revise Dr. Hatch's nomenclature slightly, for there seems to be no true limburgite in East Lothian. Both here and in the intrusive phono- litic trachytes important evidence has been obtained supporting Pirrson's view that analcite may occur as a primary constituent of * " An Analcite Diabase and other Rocks from Gullane Hill," Trans. Edin. OmV Soc, 1903, vol. viii. pp. 326-335. t" On the Monchiquite or Analcite Group of Igneous Rocks," Journ. Oeol., 1896, vol. iv. pp. 679-690. Analcite Basalts and Monchiquiles. 105 igneous rocks. The character relied chiefly upon in distinguishing the analcite occurring in these rocks from colourless glass is its posses- sion of an ill defined cleavage. The importance of this criterion has already been recognised by Dr. Evans,* who has taken the foremost place among British geologists in advocating the frequent primary origin of analcite. In the descriptions that follow there is one point especially which has been intentionally disregarded, namely, the nature of the altera- tion products which so often have replaced the olivine originally present. In the intrusive basalts, the olivine is frequently very fresh, and when altered it has generally yielded serpentine. In the lavas, however, its place is usually taken by iddingsite pseudomorphs, such as have been described by several authors, f It has not been found convenient to follow strictly Dr. Hatch's procedure of describing separately the lavas and the intrusions. On the one hand, especially among the trachytes, it is often imposs- ible to determine whether a particular sheet is contemporaneous or not, while on the other hand such a treatment would at times lead to unnecessary repetition. In a general way, therefore, it has been decided to describe the rocks in order of decreasing basicity, but at the same time to retain the consideration of their intrusive or extrusive characters as a modifying influence in determining the arrangement. Later Intrusions. i. analcite basalts and monchiquites. Basalts of the post-effusive epoch in the volcanic history of East Lothian are well represented in the coastal region between Gullane and Eyebroughy Scar (for localities situated in one-inch map 41, see Fig. 3, Chap. VII.). They are here seen in unmistakable relationship to the trachytic lava group, since they are intruded into the sediments overlying the latter. Probably most of the very basic intrusions of the North Berwick and Dunbar shores and of Chesters Quarry (Whitelaw Hill), Limplum, and Fernylee, with other less conspicuous examples, also belong to this epoch, since their frequently obvious intrusive character in the field and their close penological affinities under the microscope unite them into a natural group. This view, however, is not very firmly established, since Mr. ('lough describes a lava which occurs low down in the volcanic sequence, and yet presents the microscopic characters of the later intrusives : it is, however, too decomposed to allow of very precise investigation. Mr. Barrow also states that the monchiquite at North Berwick Abbey, associated with the basement ash, has the field characters of a lava, though its relations to surrounding rocks are nowhere exposed. It also seems natural, taking field evidence alone, to assign the Dunbar plugs to an early stage in the vulcanicity of the district. In the field these very basic intrusions occur chiefly as sills, and *"A Monchiquite from Mount Girnar Jungart (Kathiawar)," Q.J.U.S., 1901, vol. lvii. p. 46. + A. Bembrose, Q.J.O.S., 1895, vol. li. pp. (U3-616 ; B. R. Young, Trans. Edin. Oeol. Soc, 1903, vol. viii., pt. iii., p. 327; A. Harker, "Tertiary Igneous Rocks of Skye," Mem. Oeol. Survey, 1904, p. 34. 106 Petrology. are, typically, fine grained black columnar rocks with small but recog- nisable phenocrysts of olivine and augite set in a groundmass glisten- ing with minute prisms of augite. The less felspathic types generally show patches distinguished by a low lustre, probably due to the presence of analcite and other zeolites enclosing the earlier formed minerals of the groundmass, a feature which is especially noticeable in the rock from Kidlaw Quarry, where the analcite crystals are as much as \ inch across. Under the microscope most of these intrusions show themselves to be members of a rock series, in Brogger's sense, including every gradation from augite monchiquite to basalt. This continuous series has, however, been arbitrarily divided into two groups or types (a and b), and a third, the Kidlaw type (c), has been added, to include two occurrences which stand somewhat apart from the others. (a) The Monchiquites, together with doubtfid Nepheline Basalts. These are rocks of porphyritio structure with abundant phenocrysts of olivine and augite. Hornblende is, however, absent. The groundmass of the monchiquites consists of small prisms of augite of the second generation, embedded in an isotropic matrix which consists for the most part of analcite showing no evidence of having been derived from nepheline. In the doubtful nepheline basalts, the groundmass contains both clear analcite and certain undetermined minerals, one of them possibly a variety of nepheline distinguished by its low refractive index. It is described in the sequel under the provisional title of nepheline x. In both types felspar is present only in very small amounts. Felspar-free monchiquite has only been obtained in one locality, Stenton, where it occurs as an irregular intrusion ; monchiquite with very little felspar occurs in the same neighbourhood, near Pressmennan Loch, as a three-foot dyke in the Upper Old Red Sandstone series (in this case with a partially glassy base), and, at North Berwick Abbey, associated with the basement ash. The doubtful nepheline basalts are represented at Chesters Quarry * (White- law Hill) by a sill in the Upper Old Red Sandstone series, and at Lrmplum by another sill in the basement ash. The Limplum sill contains an increasing pro- portion of felspar as it is traced to the south through Baro Wood and Sheriffside to Yester, and in these localities furnishes examples of the succeeding division. (b) Fine grained Porphyritic Olivine Analcite Basalts which carry a variable though generally small amount of felspar in the groundmass, together with clear colourless analcite and sometimes a little brown glass. In the latter case they closely resemble the basalts of the Hillhouse and Dalmeny types of Mid and West Lothian, described by Dr. Hatch. | Examples are numerous, and we need only mention the sills along the shore from Gullane Bay to Eye- broughy Scar, together with those constituting the islands of Fidra and the Lamb, the plug-like intrusions of the Castle and Dove rocks at Dunbar (Plate II.), and the intrusive mass associated with the volcanic group at Fernylee near Oldhamstocks. (c) The Kidlaw Type is a fine grained porphyritic olivine analcite basalt poorer in phenocrysts than the other two groups. Augite in minute prisms still plays a predominant role in the groundmass, and is accompanied by felspar, biotite and analcite. The prominence of orthoclase among the felspars, and a marked increase in the amount of biotite are the distinguishing features of this type compared with its allies of the two preceding groups ; but the most in- teresting feature of the Kidlaw rock is the fact that its analcite occurs in large distinct crystals. Two examples of the Kidlaw type arc known, viz. — the large Kidlaw sill (three miles west of Gifford) intruded into strata of Upper Old Red Sandstone age, and the Knockenhair intrusion in the Dunbar ash neck, half a mile west of the town. * Hatch, Trans. Roy. Soc. Edin., 1892, vol. xxxvii. pp. 116, 117, plate i. fig. 1. f Quoted by Sir A. Geikie, " Ann. Address of Pres.," Q.J.O.S., 1892, xlviii. pp. 129, 130 ; cf. also " Ancient Volcanoes of Great Britain," 1897, vol. i. p. 418, where Professor Watts (quotedfiby Sir A. Geikie) employs the name picrite type to include Hillhouse group of basalts. Analcite Basalts and Monchiquites. 107 Now that these three types have been briefly distinguished in their main features, it will be convenient to take the two first together and describe the many points of interest which they present in common, reserving the Kidlaw rock for separate consideration. (a and b) Monchiquites, doubtful Nepheline Basalts and Analcite Basalts. — The phenocrysts are of olivine and augite, with very rarely an exceedingly corroded felspar. Olivine preponderates over augite, and, as a rule, both occur with good crystal outlines. The latter not infrequently shows lamellar twinning, and possesses the purplish brown tint, deeper at the margins, which suggests a high content of titanium. Augite recurs very abundantly in the goundmass in beautifully formed minute prisms, which are of the same colour as the outer zones of the phenocrysts. Professor Hull,* as early as 1873, showed that the possession of this type of groundmass (with minute prisms of augite) distinguished the Limerick Carboniferous basalts from their neighbours of Tertiary age in Antrim, while Dr. Teall "j" pointed out that both in this respect and in the frequent occurrence of porphyritic augite { the basalts of the Central Valley of Scotland and those of Limerick, resemble many of the recent and Tertiary Continental examples. Moreover, a Carboniferous basalt from Limerick yielded to Allport § a partially serpentinised " nest of olivine," which, as Dr. Teall || pointed out, suggested the former presence of olivine nodules, thus enhancing the resemblance of this suite or rocks to the products of the much more recent eruptions of the Continent. " Olivine nodules " resemble in structure and com- position various types of peridotite, but with certain significant differences ; two of these distinctions have been emphasised by Max Bauer, If namely, that the olivine of the nodules has a tendency to idiomorphism and also contains bands rich in curiously branching fluid inclusions.** This author holds with many others ff that the nodules are not exogenic fragments of peridotite caught up accident- ally by the basalt, but true endogenic secretions from the magma of the latter formed under intratelluric conditions. No oh vine nodules have been recorded from the lavas of the Brito-Icelandic Tertiary province, |f and among the intrusive rocks the only analo- gous example appears to be that cited by Judd §§ of troctohte frag- ments in the Fair Head sill (Antrim). The first record of an olivine nodule from the Carboniferous rocks * Geol. Mag., 1873, vol. x. p. 153. t " Brit. Petr.," 1888, p. 247, plate xxiv. fig. 2. j For scarcity of phenocrysts of augite in Brito-Icelandic Tertiary province, cf. Judd, " Gabbros, Dolerites and Basalts, of Tertiary Age, in Scotland and Ireland," Q.J.6.S., 1886, vol. xlii. p. 71. § " Microscopic Structure and Composition of British Carboniferous Dolerites," Q.J.G.S., 1874, vol. xxx. p. 552. || " Brit. Petr.," 1888, p. 246. IT " Der Basalt vom Stempel bei Marburg und einige Einschlusse desselben," N. Jahrb. f. Mineral, V.8.W., 1891, ii. pp. 191, 200. ** Recently R. Campbell and A. Stenhouse have described branching fluid in- clusions in the olivines of the well-known Inchcolm picrite; cf. " The Geology of Inchcolm," Trans. Geol. Soc. Edin., 1908, vol. ix. p. 125. tt For references consult Zirkel, " Urausscheid. in Rhein. Basalten," 1903, pp. 108- 111 ; Lacroix, " Enclaves des Roches Volcaniques," 1893, pp. 483-499. X% A. Harker, " Tertiary Igneous Rocks of Skye," Mem. Geol. Survey, 1904, pp. 39, 40. §§ Q.J.G.S., 1886, vol. xlii. p. 71, plate vii. 108 Petrology. of the Central Valley seems to be due to Prof. B. E. Young,* who noticed in the upper Gullane Head sill of this district certain pseudo- morphs " clustered together into what were at one time olivine nodules." They measure three or four inches in diameter. Later Dr. Falconer, f in his petrographical description of the Bathgate Hills, states that " nodular masses of various minerals sometimes as large as marbles, and perhaps to some extent xenocrystic, may be picked out of many of the lavas. These include intergrowths of augite and anorthite, and augite and olivine, usually much corroded by the • basaltic magma." It has now been found that small olivine nodules are not at all infrequent in the group of rocks at present under con- sideration, though the most numerous examples are found in the Kidlaw rock — to be described later. A fine example was obtained by Mr. Maconochie in the island of the Lamb (11898) (Plate X. Fig. 1). It is about half an inch long and a quarter broad, and is chiefly composed of olivine, but also contains a very pale green diopside and irregular patches of picotite. The structure is entirely allotriomorphic. Some of the irregular patches of picotite are embedded in the olivine. The latter occurs in big grains, many of which show a lamellar pseudo-twinning, probably the result of strain ; the lamellae, which are broad and bounded by parallel edges, extinguish in very slightly different positions, and when the optical orientation of adjoining lamellae is investigated in convergent light it is found to differ only to a trifling extent. Both the olivine and diopside possess the narrow bands of fluid inclusions, regarded by Bauer as typical of the true olivine nodules, but no sign of idiomorphism was observed in the crystals. Like the continental types this nodule shows notable corrosion effects. The diopside is the more readily attacked, apparently, for it is always altered at its contacts with the basalt, and usually also at its internal junctions against olivine, in the latter case it is, moreover, affected to a greater extent than the olivine. The alteration undergone by either of these minerals is of a special type apparently leading to the formation of a zone of re-crystallisation about the various crystals, and as a rule the recrystallised product is not in optical continuity with the original crystal. The borders thus produced have a very peculiar structure due to the formation of innumerable branching inclusions (probably originally filled by glass) % which give to those parts affected a remark- able resemblance to sections across a dendrodont tooth. Both minerals, in contact with picotite, are frequently similarly altered, in which case the picotite assumes a black border, evidently also due to interaction at the junction. It is noticeable that the recrystal- lised pyroxene retains its original tint and does not assume that of the general augite of the rock. There are, however, other nodules which appear to have been formed under conditions more similar to those which regulated the crystallisation of the ordinary phenocrysts. Normal violet-brown augite enters into the constitution of these instead of diopside, and while sometimes this is the only constituent it is often also found * Trans. Edin. Geol. trace — 0-07 V trace MnO 018 trace trace 0-29 MgO 4-90 5-15 5-23 3 02 CaO 6-41 7-98 6-53 5-26 SrO •06 — trace BaO •08 — 0-09 Na 2 . 4-97 5-47 3-39 5-21 K 2 2-85 3-99 3-05 2-10 Li 2 trace — — — H 2 below 105° C. . 1-08 016 } 3-87 1-08 H 2 above 105° C. 3-16 0-22 1-61 P 2 6 . . 0-76 0-84 0-53 1-47 C0 2 1-06 — — P — — 018 S nt. fd. 03 10053 •07 (lessOforP) Total 99-88 99-95 99-85 100-46 Sp. gr. . . — — — 2-79 Trachytes. 127 I. Kulaite. Scar beneath Blaikie Heugh basalt on which latter stands the Balfour monument. S. of Traprain Law (11858). Anal. W. Pollard. CI not found. A. Kulaite. Well digging Kula, Asia Minor. Anal. H. S. Washington, quoted from Journ. Geol., 1900, vol. viii. p. 613. Water expelled below and above 110° C. B. Hornblende Basalt. Yellowstone Park. Quoted from Iddings, Mon. U.S.O.S., 1899, vol. xxxii. pt. ii. p. 340. C. Mugearite. Lower member of same composite intrusion of which A, p. 122, is the upper. Skye. Anal. W. Pollard, quoted from Harker, " Tert. Ig. Rocks of Skye," Mem. Geol. Survey, 1904, p. 263. The kulaites are distinctly less basic rocks than the true hornblende basalts, for the latter possess well-marked limburgitic affinities. Considering its somewhat decomposed condition, it will be seen that the East Lothian example agrees well in composition with the original kulaite, though an important difference distinguishes the titanium content of the two rocks. The close correspondence of these kulaite analyses with that of the Craigleith essexite, given earlier, is also very noteworthy, especially when attention is paid to the mineralogical differences * between the two types. The trachydolerites are, it is well known, the effusive representatives of the essexite magma,"]" and Mr. Harker, J in discussing the analysis of the Skye mugearite quoted above, has already pointed out that " the only important point distinguishing it from the true essexites is its lower proportion of lime." The kulaites, so far as one can judge at present, appear to be richer in lime and magnesia and poorer in iron oxides than the mugearites, and possess, even more definitely than the latter, a typical essexite composition. Trachytes. The trachyte lava group overlies the basaltic series ; there are also several conspicuous examples of trachytic intrusions, which are doubtless of the same general age as the lavas, but which occur at various stratigraphical levels. Taken as a whole, the great feature of the East Lothian trachytes is the constancy with which their ferromagnesian constituent is a green augite rich in soda ; for the latter is found in all subdivisions, alike in the quartz trachyte of Dirleton Quarry (1860), in the quartz banakite of Bangly Quarry (625), in the normal trachytes and in the trachytic phonolite of Traprain Law. It is generally present in two generations, when the phenocrysts are occasionally idiomorphic and may show con- spicuous resorption phenomena (836B) (Plate VIII. Fig. 3). But in the groundmass it never builds idiomorphic prisms, and so is dis- tinguished from the augite of the basalts by its habit no less than by its colour ; it always occurs either in exceedingly ragged ophitic plates, or in small granules. Aegirine has not been recognised as an associate of this augite. It is not often that the tuffs are suificiently well preserved to repay microscopic study. The bed of ash (11379) exposed close to the Tyne in the small burn section west of Nether Hailes, however, * Hibsch discusses an equally interesting case of the mineralogical differences which may distinguish rocks with essentially this same composition. The differences are not, however, the same in the two cases. Tsch. Min. Pet. Mitt., 1902, Heft. ii. p. 157. t Rosenbusch, " Elemente der Gesteinlehre," 1901, p. 254. t " Tert. Ig. Rocks of Skye," Mem. Geol. Survey, 1904, p. 265. 128 Petrology. furnishes excellent material where it has been hardened by a lava passing over it. The materials forming the bombs were in various conditions when ejected. Small fragments of already consolidated trachytes are frequent, the broken junction crossing phenocryst and matrix alike. At other times a large phenocryst has been ejected along with still liquid magma, which has passed into a froth, now represented by a black glass with orthoclase microlites, the vesicles being filled by a mosaic of quartz. The magma has frothed up even where it has occupied corroded hollows in the phenocrysts, thus clearly indicating the presence of large phenocrysts, in an otherwise thoroughly molten magma at the time of the eruptions. The phenocrysts show no zone of material added during consolidation. The tuffs also contains fragments of sandstone and shale. Although the various members of the trachytic group are ex- tremely similar to one another, it is still possible to distinguish certain main types, which may be stated as follows : — I. Phonolitic trachytes, including phonolites, with analcite base, and occasional zeolitic pseudomorphs which in some cases represent nepheline. Type Traprain Law. II. Trachytes proper and quartz banakites. In these there seems to be a very slight excess of silica since quartz in minute quantities can usually be detected as an original interstitial component of the groundmass. Here are included : — («) Quartz banakites, trachytes that is with frequent plagioclase pheno- crysts, and with a little quartz in the groundmass, Bangly Quarry, 2 m. W.N.W. of Haddington (625) (Plate III. Fig. 3). (6) Porphyritic sanidine trachytes, abundant in E. Lothian, e.g., Peppercraig Quarry, Haddington (616). (c) Non-porphyritic trachytes. These may be either orthophyric or trachytic. The latter structure is associated as usual with an increase in the amount of interstitial matter originally present, but in the rocks treated together here, decomposition has rendered the original nature of this material uncertain. The two groups are represented respectively in the two large intrusions of Pencraig (10854) and Garvald (11243). (d) The quartz trachytes. Here interstitial quartz takes a sufficiently important place in the groundmass to make its presence readily recog- nisable. They are represented by the porphyritic trachyte of Dirleton Quarry (I860) and the non-porphyritic trachyte of Eyebroughy Scar (10827). I. THE PHONOLITIC TRACHYTES. Four intrusions are included here, namely, Traprain Law with its satellite sill of Hairy Craig, and the two isolated stocks, North Berwick Law and the Bass Eock (see frontispiece). The Traprain Law rock, in hand specimens, may be either pink or grey, usually showing, if the specimen be taken from near the margin, a marked banded flow structure. The rock is porphyritic, and in the interior of the quarry markedly coarse-grained, so that the felspar and the augite can be readily recognised with the naked eye. Under the microscope * a few phenocrysts of sanidine appear set in a groundmass, which, as a rule, is typically trachytic in structure, * Hatch, Trans. Roy. Soc. Edin., 1892, vol. xxxvii. plate ii. fig. 1. Phonolitic Trachytes. 129 though in the coarser portions it approaches to orthophyric. The green augite occurs in ragged plates fitting in between the sanidine laths in ophitic fashion ; where the banded flow structure is observed (4529), however, the augite occurs as small granules. The banding is shown, under the microscope, merely by the decomposition of the felspars, and those bands which appear dark in the hand specimen consist chiefly of laths of sanidine, which are fresh and transparent. A little apatite is present in crystals both of early and late consolidation, and rounded crystals of magnetite occur arranged together into small groups. Analcite is abundant between the felspar laths and in the more orthophyric varieties constitutes small patches, still allotrio- morphic to the sanidines. In such a position it is scarcely probable that the analcite represents a mineral which is so constantly idio- morphic in its behaviour towards orthoclase as is nepheline ; it is probable that this interstitial analcite is primary, in part perhaps derived from the pre-consolidation alteration of the soda-rich felspars. Interesting evidence on this point is yielded by an analcite vein traversing one of the microscopic sections (4529). There is no sign here of any breaking of the felspars along the course of the vein. On the other hand, their projecting terminations are delicately idiomorphic, and it is obvious that the formation of the vein was accomplished during the consolidation period of the rock. At the same time, the felspars for some short distance on either side are rendered turbid by decomposition products, pointing to the corrosive action of the magma, copiously charged with water, which came to be relegated to this interspace. The original presence of nepheline is, however, testified to by certain small areas of analcite showing characteristic four- and six-sided sections, so that Rosenbusch, confirming Dr. Hatch's * determination, has placed the rock among his trachytic phonolites. At the time no other phonolite was known in Britain except the Wolf Rock, Cornwall, but Mr. Barron f and Mr. H. J. Seymour J have since described similar types from among the intrusive rocks of this age § in the South of Scotland. The rock occasionally carries small inclusions (11788) rich in green augite and iron ore, implanted in small allotrimorphic plates of sanidine. Hairy Craig (11355). A fine-grained porphyritic rock, closely resembling Traprain Law except that biptite occurs more frequently among the phenocrysts ; in Traprain Law specimens, this mineral has very seldom been observed. There occur certain zeolitic patches with a concentric zonal arrangement of felspar microlites. Bass Rock \\ (10795). New material from the Lighthouse founda- tions shows the close relationship of this rock to Traprain Law. It is, however, non-porphyritic, has an orthophyric groundmass, and carries less analcite than occurs in Traprain Law. * Trans. Roy. Soc. Edin., 1892, vol. xxxvii. p. 125. t Oeol. Mar/., 1896, 373-375. % Sum. of Prog. Oeol. Survey for 1900 (1901), p. 164. § This is the view held by Dr. Peach, who mapped the rocks in question for Geol. Survey. Barron, on the other hand, has described the riebekite phonolite from the Eildon Hills as a lava of Upper Old Red Sandstone age. || Hatch, Tram. Roy. Soc. Edin., 1892, vol. xxxvii, plate i. fig. 3. 130 Petrology. North Berwick Law. New and very fresh material has been gathered from the flat above the Law, which proves it to be very similar to the Bass, but porphyritic. In addition to allotriomorphic analcite patches, there are certain pseudomorphs suggesting the former presence of nepheline. In some specimens * (4521) a microporphyritic structure is observable, and big laths of felspar are found associated with smaller microlites. The slides showing this structure are not sufficiently fresh to reward study, but it is significant that they cannot be dis- tinguished from the rock of the Lock Hill pit (640), two miles south of Aberlady, described by Dr. Hatch.f If fresh material could be obtained, this rock would also probably find a place among the phonolitic trachytes. All these rocks have been analysed, with the exception of the Hairy Craig, and the analyses have already appeared in Dr. Hatch's paper .J Dr. Pollard has also determined the alkalies in a duplicate specimen of the Traprain Law rock. I. II. III. IV. A. Si0 2 56-8 57-50 60 15 56-49 Ti0 2 0-5 — — — 0-74 A1 2 3 19-7 — 18-89 18-04 18-77 Fe 2 3 FeO 2-2 3-5 — | 7-51 4-44 1-82 3-00 1-46 MnO 0-2 — — 0-13 032 MgO 0-4 — 1-33 0-98 063 CaO 22 — 1-80 1-68 3 29 Na 2 4'3 6-79 5-71 6-07 7-10 K 2 7 1 641 5 90 4-15 5-18 H 2 2-5 ! — 1-70 ! 2 06 1 1-83 p 2 o 6 — — — — 0-27 C0 2 — — 1-00 Total 99-4 — 10034 99-52 100-08 Sp.gr 2-588 — — 2-46 2-517 1 Loss on ignition. I. Traprain Law. Anal. J. H. Player (4526, etc.). II. Traprain Law. Anal. W. Pollard (4529) (Li 2 ? trace). III. The Bass Rock. Anal. G. Barrow. IV. North Berwick Law. Anal. J. S. G. Wilson (835). A. Trachytic phonolite, Ziegenberg, near Nestersitz, Bohemian Mittelgebirge. Quoted from Rosenbusch, "Elemente der Gesteinlehre," 1901, p. 292. These analyses show that Traprain Law and the Bass Rock agree well with the trachytic phonolites, while North Berwick Law, with increasing silica and decreasing alkalies, approaches the trachytes very closely. * Hatch, Trans. Roy. Soc. Edin., 1892, vol. xxxvii. plate i. fig. 4. f Trans. Roy. Soc. Edin., 1892, vol. xxxvii. pp. 121, 122. % Trans. Roy. Soc. Edin., 1892, vol. xxxvii. pp. 123-125. Trachytes and Quartz Banakites. 13] II. TRACHYTES PROPER AND QUARTZ BANAKITES. (a and b) Quartz Banakites and Porphyritic Trachytes. — Dr. Hatch's* description leaves very little to be added. The field characteristic of the group is the presence of large felspar phenocrysts, which, in the trachytes proper, are simply twinned, and these he in a ground- mass which may be dark grey, brown, mauve or yellow, and which has usually a saccharoidal lustre due to the small felspars of the groundmass. It should be remembered that Dr. Hatch fully described the peculiarities of the rocks now placed with the quartz banakites, although he did not place them in a separate group. (a) The Quartz Banakites. — The East Lothian examples from Bangly Quarry and Skid Hillf show the same association of basic plagioclase phenocrysts with a thoroughly trachytic ground- mass as characterises the original specimens from Yellowstone Park.J The biotite phenocrysts of the latter are, however, wanting. The majority of their numerous felspar phenocrysts are plagioclase, some even as basic as labradorite. They are usually zoned with orthoclase, and the latter can be readily detected by a simple extension of Michel Levy's § method of " equal illumination " for investigating zoned felspars. He has pointed out that for two minerals in a thin slice which are polarising in greys and whites there are four positions of equal illumination between crossed nicols. If the mi n erals be juxtaposed with partial overlapping, two of these positions of equal illumination will hold for the overlapping portions and they are termed positions of " total equal illumination " by Levy, in contrast to the other two positions for which overlapping portions tend to produce compensation. The positions of total equal illumination likewise hold approximately for a whole isomorphic series if these are present in similar orientation, as is the case with the various zones of a plagio- clase crystal. When orthoclase is present as the outer zone of such a crystal it may therefore be readily detected, for when the various zones of plagioclases become but faintly distinguishable in the position of approximate " equal illumination," the orthoclase zone will in general still be conspicuous. A special peculiarity in the Bangly rock is the local development of numerous large idiomorphic tabular phenocrysts of sanidine, often measuring as much as two inches across. They enclose the earlier and much smaller basic felspars in apparently a perfectly haphazard manner (13246), although it is quite possible that each one may also possess a small basic kernel with which it is in crystallographic con- tinuity. The ferromagnesian constituent of the East Lothian quartz banakites is the aegirine-augite already referred to ; it occurs in rather large idiomorphic crystals. The groundmass is essentially * Trans. Boy. Soc. Mdin., 1892, vol. xxxvii. pp. 119-121. t Skid Hill Quarry lies to the west of the Haddington road at the very summit of the Garleton Hills. % Iddings, Mon. U.S.6.S., 1899, vol. xxxii. pt. ii. p. 350, plate 38. §" Etude sur la Determination des Feldspaths dans les Plaques Minces." 189(5, pt. ii. 132 Petrology. made up of orthoclase laths with a very small proportion of inter- stitial quartz. (6) The Porphyritic Trachytes. — Every gradation exists between this group and the last, but as a rule sanidine greatly preponderates over plagioclase among the phenocrysts, which all the same have constantly a corroded aspect and are surrounded by a zone dating from the groundmass period of consolidation and rich in inclusions. These facts have led Dr. Hatch to adopt the view that they must be regarded as the products of the " intratelluric " phase of consolidation. Glomero-porphyritic aggregates are common. Dr. Hatch's view finds support in the character of the phenocrysts occurring in the trachytic ashes already described. In the case, however, of certain exceptional phenocrysts, such as the large and obviously late-formed sanidine phenocrysts of Bangly Quarry, already described, this generalisation does not apply. The local distribution, in especial, of these crystals has led Mr. Barrow to the conclusion that they have formed after the rock had come to rest. The augite of these rocks has already been described. Apatite is not at all an infrequent accessory in large clouded crystals of early consolidation, and clear thinner crystals probably belonging to a later date. Iron ores occur with a tendency to globular form, perhaps due to corrosion, and are specially well represented in the Kae Heughs * trachyte (4522). A little interstitial quartz may generally be detected — Peppercraig f (616). (c) N on- Porphyritic Trachytes. — These resemble their porphyritic allies both in the hand specimen and under the microscope, except for the absence of felspar phenocrysts. Orthophyric varieties are well represented in the big Pencraig J intrusion, near East Linton (10854), at Craigy Hill, east side of road at summit of the Garleton Hills (636), and throughout most of the country south of the Tyne. The Pencraig trachyte shows minute patches of interstitial quartz. The varieties with trachytic structure are best represented in the Garvald intrusion (11243) and in the slaggy lava (11240) north of the Dunbar-Gifford fault in the same district. (d) The Quartz Trachytes § are an interesting division in which the interstitial quartz already mentioned as occurring in several of the other trachytes becomes sufficiently important to attract attention. The beautiful porphyritic trachyte of Craig's Quarry, Dirleton (I860") is the best example. The structure of the ground- mass is trachytic with small patches of interstitial quartz here and there into which the sanidine laths project. Both in its amount and its method of distribution it recalls exactly the behaviour of the analcite in the groundmass of Traprain Law. Eyebroughy Scar * The Kae Heughs constitute an escarpment facing north on the east side of the road at the summit of the Garleton Hills. ■f Hatch, Trans. Boy. Soc. Mdin., 1892, vol. xxxvii. plate ii. fig. 2. ± Figured by Geikie, Trans. Roy. Soc. Edin., 1880, vol. xxix. plate xii. figs. 7, 8. § These rocks should perhaps be classed with the intrusive Carboniferous '" trachytes or quartzose porphyrites " of the Limerick basin, for which Professor Watts has suggested the name ivernite. " Guide to the Collections of Rocks and Fossils belonging to the Geological Survey of Ireland," 1895, p. 93. Trachytes and Quartz Banakites. 133 (10827), on the coast, is a less conspicuous example of a non-porphyritic quartz trachyte. A. I. II. III. IV. V. SiO., 60-89 58-50 59 50 6135 62-50 62-61 Ti0 2 0-49 — — — — — A1 2 3 1714 2112 18-25 1688 18-51 18-17 Fe,0 3 3 32 4-68 4-81 0-41 } 4-39 32 FeO 95 — 2 34 5 01 4-25 MnO 09 — — 26 — 021 NiO 019 — — — — — MgO 116 093 070 44 0-61 0-74 CaO 3 58 3-70 210 239 2-00 2 58 Na 2 4-54 3 90 5 03 5-26 3 44 649 K 2 571 5-84 630 6-12 631 4-02 H,0 161 2-00 1 1-60' 1-70 1 2-10 1 0-80' P 5 5 0-27 — — — Total 99-94 10067 10063 9932 9986 10019 Sp. gr. — — — 26 — 26 1 Loss on ignition. A. Quartz Banakite. Yellowstone Park. Anal. W. A. Melville, quoted from Iddings, Mon. U.S.G.S., 1899, vol. xxxii. pt. ii. p. 347. I. Quartz Banakite. Bangly Quarry (625). Anal. A. Dick, jun. This and succeeding analyses are quoted from Hatch, Trans. Roy. Soc. Edin., 1892, vol. xxxvii. p. 122. II. Porph. Trachyte. Phantassie, \ mile S.E. of Hopetoun Monument (622). Anal. A. Dick, jun. III. Ditto. Kae Heughs (635). Anal. J. S. Grant Wilson. IV. Ditto. Hopetoun Monument (620). Anal. Geo. Barrow. V. Ditto. Peppercraig (615). Anal. J. S. Grant Wilson. The analyses show how closely the quartz banakites of East Lothian and the Yellowstone Park agree in composition, and how intimately the former are united to the other trachytes of the district. All these rocks correspond in composition to varieties of the alkali- syenite magma, approaching, in the case of the phonolitic trachytes, to that of the nepheline syenites. It is sufficiently clear, then, that East Lothian in Lower Carboni- ferous times formed part of a petrographical province which possessed well-marked, though not extreme, alkali character. We know its products, basic, intermediate and acid, both as lavas and as hypabyssal intrusions, and it is clear that if the plutonic rocks belonging to this complex were exposed to view they would exhibit some such associa- tion of types as can now be studied in the classical district of Christiania. e. b. b. CHAPTER XL CAKBONIFEROUS LIMESTONE SERIES. Lower Limestone Group. district south-east op dunbar. The Carboniferous Limestone series extends along the coast for rather more than four miles in a south-easterly direction, from near the mouth of Broxburn to Long Craig, and forms an area which stretches inland, near Little Pinkerton and Thornton, nearly two miles. The south boundary on the coast at Long Craig is formed by faults which throw down to the north, but, perhaps, are not very large (see Chapter VI.). For a mile north-west of these dislocations the dip is generally northerly, often from 6° to 10°, so that as we go west from the lowest limestone — the Long Craig Lower Limestone — we reach one after the other the seven or eight higher limestones which are known in the district, which all belong to the Lower Limestone group. The highest limestone — the Barness East Limestone — is that seen near low-water mark near the foot of Dry Burn. In this locality the dip changes from north to north-east, and a little further north, near the promontory of Barness,* east of Catcraig, it becomes east, so that as we proceed westward from this promontory we reach lower beds, down to a sandstone which comes below the Long Craig Middle Lime- stone. North-west of this sandstone there is more uncertainty, partly owing to a wide covering of sand, and partly on account of faults and folds. A broad dolerite dyke, a little north-west of the White Sands, seems to be in a line of fault which has a downthrow to the north- west of about 100 ft., bringing the base of the Chapel Point Lime- stone, the highest limestone but two, against a lower limestone — the Skater aw Middle Limestone — on the south-east. Between this dyke and the Vaults the Chapel Point Limestone appears to make four separate outcrops, in consequence of folds and faults, which strike E.N.E. ; but for a quarter of a mile north-east of the Vaults the beds are less disturbed and dip north-west, and we soon pass the two highest limestones, and reach a group of beds which may represent the bottom part of the Edge Coal group of Mid- Lothian, but only about 70 ft. of them are seen. Near the mouth of Broxburn an obscure tract of sand and gravel comes in, east of which the three highest limestones and the overlying beds again appear. All these limestones and the other beds become reversed near low-water mark and acquire a nearly north and south strike, parallel to that of the big fault which brings up, on the west Bide, beds belonging to the Cementstone group. This fault probably * Not named on the one-inch map. 134 District South-east of Dunbar. 135 forms the western boundary of the Carboniferous Limestone series all the way from the coast to Little Pinkerton, near which place it apparently meets another large fault, with a downthrow in the same direction, and forms with it one line of disturbance — the Inner- wick fault. In the part of Dry Burn on the north-east side of the Innerwick fault some of the Calciferous sandstones emerge from beneath the Carboniferous Limestone series, and it is probable that a little on the south side of this burn these beds again emerge and extend towards Long Craig in an east or slightly north of east direction. Excellent sections occur on the coast and also at the east end of the railway cutting near Broxmouth, but the latter only shows the lower beds. Inland exposures are rare, and the boundaries of the different limestones are to a large extent conjectural. The following section, in descending order, has been constructed from the coast section, chiefly between Barness and Thorntonloch : — Ft. in. 62 103 D* Ft. in. Barness East Limestone from 2 ft. to 6 Strata, chiefly sandstone 50 °i Dr/burn Foot impure limestone or calcareous sandstone from 1 ft. to 2 SI Sandstone and shale 10 Chapel Point Limestone . . 9 ft. or 10 Shale and thin coal smut 3 °1 Fireclay or ganister, and sandstone 20 ° Thin flaggy sandstone and shale from 70 ft. to 80 0} Skateraw Upper Limestone from 1 ft. to 2 Black shale from 3 ft. to 5 Skateraw Middle Limestone . . from 16 ft. to 18 Coal from 4 in. to 6 1 Fireclay ■with small calcareous lumps i 1 4 Shale and fireclay 6 6 J Skateraw Lower Limestone from 2 ft. to 4 Thin coal in places Shale and sandstone 23 Long Craig Upper Limestone . . 18 Thin coal in places Shale, partly sandy from 2 ft. to 5 Long Craig Middle Limestone . . from 3 ft. to 6 Shale and sandstone 25 8 6 285 6 Long Craig Lower Limestone, mixed with bands of calcareous shale : 9 feet seen. In the original edition of the one-inch map the Barness East Limestone is called No. 5 Limestone, the Chapel Point Limestone the No. 4, the Skateraw Middle Limestone the No. 3, and the Long Craig Upper Limestone the No. 2. The Long Craig Lower Limestone at Long Craig appears to be called No. 1, but in the first edition of the map the Long Craig Middle Limestone at Catcraig is indicated in the Memoir, f by this number. The total thickness from the top of the highest to the bottom of the lowest limestone is, no doubt, rather more than 300 ft. The thickness of all the limestones, and notably calcareous beds, is esti- mated to be less than one-third of the whole section, but below the * The letters A, B, C, D have been added to certain of the limestones to indicate the correlation with the limestones in the Aberlady and St. Monans sections, t " Geology of East Lothian," Mem. Geo!. Survey, 1866, p. 74. Ft. 12 2 1 in. 3 24 39 3 136 Carboniferous Limestone Series. top of the Skateraw Upper Limestone the total thickness of limestone is probably rather more than that of the other beds. The Long Craig Lower Limestone is better seen in the railway cutting near Broxmouth, where it is vertical, than on the shore. The section in the cutting has been carefully examined by Mr. Macconochie, and is as follows : — Irumpy limestone with shale Calcareous shale Soft dark alum shale with fish coprolites and Lingvla Caliny limestone and calcareous shale with abundant Lithostrotion, in some parts, and remains of Polyzoa On the shore only seven or eight feet of this limestone is seen, and below these come two or three feet of shale, but these may merely represent one of the shaly partings in the cutting. In a boring recently made at Cater aig the total thickness of the Long Craig Lower Limestone, including " limy fakes," etc., is 18 ft., and the strata inter- vening between it and the Long Craig Middle Limestone amount to 30 ft. The Long Craig Middle Limestone is a white or cream-coloured band with very lumpy bedding planes, and unusually rich in corals. In the railway cutting it is only separated from the overlying lime- stone by about three feet of shale, which is itself somewhat cal- careous. On the shore 130 yds. north-east of Catcraig houses it is better seen than at Long Craig, and is richer in corals, especially in large specimens of Zaphrentis and Lithostrotion. The latter coral, indeed, forms all the upper part of the limestone for a length of more than 30 yds. along the shore (Plate IV.) : the top is indented by many close basin-shaped hollows (Plate V.), often a foot or two deep, and three to four feet in diameter, in which has been deposited the underclay of the overlying coal. This underclay contains large pieces of Stigmaria with thin rootlets spreading far out into the rock at the sides, part of which is an impure calcareous bed that passes down into the purer limestone below, and has probably in great part been formed from it by surf action. It seems as if the old trees had been growing on the surface of the coral mass very soon after it had been formed, but perhaps after it had experienced a slight elevation. On the north side of Dry Burn the Long Craig Middle Limestone is seen once more, and again the top is marked by little hollows bke those near Catcraig : the parting between it and the Long Craig Upper Limestone is from three to five feet thick, and the latter limestone is at least 22 ft., which is more than usual in this district. The Long Craig Upper Limestone is pale or cream-coloured, and characterised by knobby bedding planes, like those in the Long Craig Middle Limestone. On the coast near Catcraig the basal portion of the limestone is a calcareous shale, two or three feet thick, which is richly fossiliferous, and contains Schizophoria resupinata (Mart.) and Productus in especial abundance. Four or five feet from the top there is a band, often about eight inches thick, which is half made up of a cup coral, Koninckophyllum. The Skateraw Lower Limestone is dark and impure, and in natural sections the whole thickness generally makes but one block or post. s < a Z SJ Q District South-east of Dunbar. 137 The lower portion is generally marked by Productus giganteus (Mart.), usually with the convexities of the valves facing upwards. It also contains large crinoid stems, and occasional lumps of Syringopora and Lithostrotion. Near Long Craig it is four feet thick, but near Catcraig only two, and in the railway cutting it does not appear to exist. The Skateraw Middle Limestone is dark grey and evenly bedded. The basal portion is a fossiliferous shale, two or three feet thick, which is especially rich in Athyrids and Spirifers. On the shore near Skateraw, the top of the lower portion contains many large crinoids. A little below the top of the limestone there is a band, usually a foot or two thick, which is crowded with Saccammina carteri Brady.* In the quarries near Oxwell Mains the Saccammina band is from one to two feet thick, and the limestone above varies from six inches to two feet, weathers with a reddish colour, and is almost entirely made up of broken crinoid stems. The characters of this limestone and of the Long Craig Upper Limestone are, as will be seen, quite distinct from one another, and we are thus able to recognise near Catcraig an east and west fault which throws the two beds together in the more northerly of the two old quarries. The Skateraw Upper Limestone is generally ferruginous and crinoidal. In different places it varies considerably both in thickness and in distance above the underlying limestone. In the quarry south-west of Oxwell Mains it is sometimes six feet thick, and is separated by more than ten feet of black shale from the lower lime- stone. The ganister beneath the Chapel Point Limestone on the south- east side of Chapel Point, has been sliced (11268), and was found by Dr. Flett to consist almost entirely of rounded grains of quartz, averaging about 2 mm. in diameter, together with a cement of quartz in optical continuity with the grains. The basal portion of the Chapel Point Limestone is an impure sandy bed, about one and a half or two feet thick, at the top of which are lumps of Lithostrotion and Chcetetes, together with large crinoid stems. Near Chapel Point and Barness, and the coast about half-way between Barness and Dryburn Foot, there are, near the middle of the bed, small lenticles of dark grey chert, which contain foraminifera and other organic remains, but none of these lenticles have been found on the north-west side of Catcraig. Saccammina carteri occurs sporadically two or three feet below the top. Most of the bed seems rather impure, and it often shows very distinct remains of Spirophyton cauda-galli near the top. North-west of Catcraig the top band is generally shaly and very rich in Spirifers, crinoids and spines of Archmocidaris. Dr. J. G. Hinde has examined various slides (10739-10742) of the chert obtained from the limestone rather more than three-quarters of a mile E.N.E. of Barness, but he reports that the chert, though full of organic remains, does not contain many that are determinable. The foraminifera determined are Endothyra and Trochammina, and in * This was recorded at Catcraig by R. Etheridge, jun., in 1873, in his paper " On the Occurrence of Foraminifera {Saccammina Carteri, Brady) in the Carboniferous Limestone Series of the East of Scotland," Trans. Geol. Soc. Edin., vol. ii. p. 225. 138 Carboniferous Limestone Series. addition to the foraminifera there are present, sponge spicules, crinoid ossicles, Entomostraca, Bryozoa, small gasteropoda and various organic remains of uncertain character. The Dryburn Foot impure limestone, or calcareous sandstone, contains remains of crinoids and plants. It makes an extensive outcrop on the shore a little north-west of Dryburn Foot, but does not seem to exist on the east side. Close to the Vaults, half a mile north-east of Broxmouth, an impure limestone, about a foot thick and with Spirophyton cauda-galli and Chcetetes, may represent this bed. The Barness East Limestone is about six feet thick near Chapel Point, but near the Barness Lighthouse it is usually only two or three, and on the north side of the east and west fault which passes about 250 yds. north of the Lighthouse, it seems very impure, and is hardly a foot thick. Near the Vaults this limestone seems repre j sented, again, by a calcareous sandstone, the upper three or four feet of which are the most calcareous, and in the map have been coloured as a limestone. This bed contains occasional worm tubes (" pipes ") and rests on a hard sandstone, about a foot thick, which is very full of worm tubes, but contains crinoid remains also. Even below this piped bed, bits of crinoid stems are occasionally seen for a depth of three or four feet. The beds which come above the Barness East Limestone, and which may represent the bottom part of the Edge Coal group of Mid- Lothian, are seen in two localities on the coast, namely, east of Barness Lighthouse, and near the mouth of Broxburn. In the former locality sandstone rests directly on the limestone — a somewhat unusual phenomenon in the Carboniferous Limestone series. The sandstone is unmixed with shale, is coarse in grain, and contains a good many big roundish lumps which possess a matrix of calcite coloured by limonite (10692). In the other locality, the beds consist chiefly of sandstone, but include also bands of shale with ironstone lumps, a bed of ganister, and a thin coal, about ten inches thick in places and perhaps 20 or 30 ft. above the limestone. The shale close to the coal contains remains of Cardiopteris polymorpha (Goppert), and it must be in a higher stratigraphical position than any other bed in which this plant is yet known. c. T. C. AREA FROM ABERLADY TO PATHHEAD. The Lower Limestone group outcrops as an irregular band from the shore of the Firth of Forth at Aberlady to Pathhead, on the western edge of the Sheet. The general dip north of the Tyne Water varies from due west to rather south of west, but a little south of the river it gradually becomes more northerly, and the trend of the out- crop changes from a north and south into a north-easterly and south- westerly direction. Throughout the greater part of this area the rock is covered by drift, and sections showing a sequence are very scarce. Isolated quarries in the principal limestones are scattered along the outcrop, but little is seen of the beds in association with them. The scarcity of bore-sections — owing to the rocks lying below the best known valuable minerals — has also helped to prevent us obtain- ing accurate knowledge of the stratigraphical sequence over much of Aberlady to Pathhead. 13 140 Carboniferous Limestone iSeries. the area. The coastal exposures at Aberlady Bay (Fig. 7) and Dalskelly Crags afford, however, excellent sections. Though but little change has been made during the resurvey in mapping the limits of the out- crop of this group, it must be understood that in many places the boundary lines have had to be drawn on very limited evidence. The correlation of the limestones seen in the different exposures has, however, been more systematically carried out than formerly (Chap.V.). The Lower Limestone group has usually in this district a breadth of outcrop of nearly a mile owing to the very gentle angle of inclina- tion at which the beds are lying, but this breadth varies somewhat with the form of the ground and local changes in direction of dip. Such changes are seen in the neighbourhood of East Salton, where, in consequence of a synclinal arrangement along an axis striking N.N.W., the outcrop makes a large tongue-like projection extending in a south-easterly direction for about two miles. In Gosford Bay, also, the rocks are arranged in a syncline, with an axis in a N.N.W. direction, and it is possible that on the shore, in some parts of this bay, there are beds that he above all the Lower Limestone group. The most complete section in this district is seen on the shore at Aberlady where the following sequence can be made out : — Ft. in. Dark shales and sandy bands, with a thin limestone, at Craigielaw Point, which is contact altered by the dolerite sill . . . . — D* Hard grey thick-bedded limestone with encrinites and Productus gigante.ua, seen near Craigielaw Point ; the base of it is also seen in the middle of the Aberlady syncline, where it forms the highest bed ( = Skateraw Middle Limestone) .. .. .. . . 12 Grey shales with calcareous and ferruginous oolitic nodules. Some beds " daugh " -like and with plant remains. A thin coal seen in the Aberlady syncline . . . . . . 20 C Hard grey limestone with Productus giganteus ( = Skateraw Lower Limestone . . . . . . . . . . 2 to Thin coal " Daugh " and sandy fakes, ripple-marked and with numerous tracks . . . . . . . . . . . . 4 to Yellow sandstone with greatly contorted bedding Fakes and shales, sandy above and limy below, ripple-marked and with numerous tracks. Some marine fossils, mostly broken or fragmentary. Many rolled fragments of shale and wood . . 8 B Limestone, nodular and dolomitic, consisting chiefly of encrinite fragments, the upper part shaly and more evenly bedded ( = Long Craig Upper Limestone) . . . . . . . . 12 to Coal Grey papery shale and " daugh " bands full of twisted rootlets A White coral limestone consisting largely of IAtliostrotion junceum and L. irregulare : also white marly bands and nests with many brachiopods ( = Long Craig Middle Limestone). One of these bands consists almost entirely of shells of " Rhynclwnella " pkurodon . . . . . . . . . . ..80 Yellow sandstones and grey papery shales with white hard oolitic beds containing rootlets . . . . . . . . . . 20 A blue calmy limestone, with encrinites, seen dipping to W.S.W. at 20° in a quarry between Aberlady Mains and the seashore, is probably near the base of the group, but its position is doubtful. On the muddy shore north of Aberlady and east of Kilspindie (Aberlady Point), lime- * The letters A, B, C, D have been added to certain of the limestones to help in their identification with the corresponding limestones in the Dunbar and St. Monans sections. 4 3 .8 4 18 10 6 Aberlady to Pathhead. 141 stone and other rocks, sometimes much contact altered by dolerite, are met with in several places as isolated patches in the mud and shingle, and these also, though doubtless representing beds in the section described above, have not been identified individually. From Kilspindie westward the section is continuous as far as Craigielaw Point, where the Peffer Burn finds an exit at low water. The beds in this section are rolling at low angles and form, first a small syncline on the east side, and then an anticline further west. Three small faults in this section have a N.N.W. direction, the same as that of the long axes of the folds. Two of these faults occur close together, the strata on either side being lowered in relation to beds that lie between them. The prevalent dip seen in the Aberlady section is southerly, this being the pitch of the folds. The strike of these folds is N.N.W. , the same as that of the folds already referred to in the synclines at Gosford Bay and in the neighbourhood of East Salton. This direction of folding differs slightly from that of the Bast Lothian Basin and the Mid-Lothian syncline and Roman Camp anticline in one-inch map 32, to the west. To the south of Ferny Ness there must be a fault, with a down- throw to the north, which probably continues inland from the southern limit of the dolerite sill, but no exposure of the fault has anywhere been detected. South of the fault some of the Aberlady limestones are again found on the shore, but the coral limestone is not seen. Two encrinital limestones, 6 ft. and 1 ft. thick, which are seen in isolated beach exposures, south of Dalskelly Crags, are probably higher than any met with in the Aberlady section. In the section north of Dalskelly Crags the highest beds are near the dolerite dyke which forms the crags. The section is as follows : — Ft. in. „ f Mudstone baked by the dolerite dyke . . . . . . — \ Dark shales and thin sandstone bands .. .. .. — Interruption of section by a strike-fault. D 7. Limestone with encrinites and thin shaly partings (=Skateraw Middle Limestone) . . . . . . . . . . 12 6. Soft grey mudstone with blue and black shales, and a thin seam of coal . . . . . . . . . . about 50 C 5. Tough limestone with " cauda-galli " markings, Productus giganteus, Lithostrotion and Cephalopods ( = Skateraw Lower Limestone) . . 4. Blue and black shales . . . . . . about 3. White and grey false-bedded sandstone . . . . ? about 2. Black shales . . . . . . . . . . about Fault here in direction of strike repeats bed. 3. White and grey false-bedded sandstone . . . . . . — 2. Black shales . . . . . . . . . . . . — B 1. Grey concretionary dolomitic limestone, very encrinital, base not seen ( = Long Craig Upper Limestone) .. .. 12 A great growth of seaweed obscures the above rocks, especially the Sandstone No. 3, and, combined with the fact that some of the beds are only exposed at low tide, renders it difficult to estimate the thicknesses accurately. The beds in this section are dipping at an angle of about 10° to the south-east, and the small faults seen have the same strike and direction of throw (down to the north) as the larger fault south of Ferny Ness. It is possible also that there are other small parallel faults with the same direction of throw which repeat the section, and 4 18 20 6 142 Carboniferous Limestone Series. keep the coral limestone below the surface, but the part of the shore between the section described above and Ferny Ness is almost com- pletely obscured by mud and shingle. Inland, limestone has been met with under 27 ft. of superficial deposits in a boring near the kennel at the east boundary of the grounds of Gosford House. A limestone with encrinites has also been quarried in these grounds, but no rocks above or below are exposed, and it is difficult to correlate it with any of the limestones in the Aberlady shore section. Proceeding southward the next sections are those along the railway near Harelaw and in the large quarries east of Longniddry Station, where the limestone is quarried and burnt for lime : the section seen in these quarries is as follows : — Ft. in. '6 4 12 10 White and yellow sandstone, top not seen Black shales . . . . . . . . . . from 3 to Blue calcareous shales with many fossils, Fenestella, Productus, Spirifer, cup corals, etc. Hard nodular encrinital limestone, bottom not seen (probably = Long Craig Upper Limestone) . . . . . . more than The same section is also seen south of the main road in the old quarries at Landridge limekilns. The sandstone can be traced for some distance south, but excepting for this no other rock is met with until we reach Gladsmuir. A bore put down on Gladsmuir farm, in search of coal, proved the following beds : — Clay Sandstone Coal Sandstone and shale Limestone Bands, etc. Calcareous shale Thin beds White sandstone Blaes Ft. in. 16 37 6 24 3 11 64 4 7 2 2 11 2 46 35 188 2| It is probable that the limestone pierced is high up in the Lower Limestone group, and that the false-bedded yellow sandstone quarried in Moffat Wood, about three-quarters of a mile further east, underlies the whole of the group. Rather less than a mile further south, a second bore put down in 1900, near Nairns Mains, a quarter of a mile west of Blinkbonny, reached a limestone after passing through about 30 ft. of drift. In the limestone quarries at Samuelston and Jerusalem, south of the main road to Haddington, the following section can be made out : — D Alternating hard blue limestone and bands of calcareous shale. Some encrinites, but fossils scarce (probably = Skateraw Middle Limestone) Obscure gap, soft beds. C Hard limestone in one set or bed (probably = Skateraw Lower Lime- stone) Pale yellow and white sandstone . . . . more than Ft. in. 12 4 3 6 6 Aberlady to Pathhead. 143 A pale nodular limestone with corals and Producti is seen in the banks of the Tyne, north of Herdmanston Mains, and resembles the coral limestone of Aberlady ( = Longcraig Middle Limestone). A good section is met with at the Salton quarries, east of Salton Hall Mains, where a small fault crosses the quarry parallel to the direction of the dip, and faults higher limestones against lower ones, thus, fortunately, exposing more beds than are usually met with in the quarries of the district. The details of this section are as follows : — Ft. in. Bands of limestone and light blue calcareous shale, top not seen . . . . . . . . ■ • more than Dark inky coloured calcareous band . . . . from 3 to i Tough eherty and nodular limestone with encrinites, Didasma, Syringopora, etc. Compact limestone crowded with Saccammina carteri Tough eherty limestone . . . . . . . . at least (This limestone with the beds above represents the Skateraw Middle Limestone and Skateraw Upper Limestone with the inter- vening beds at Dunbar.) Shale with thin coal C Tough ferruginous limestone with encrinites and Syringopora (= Skateraw Lower Limestone) Yellow sandstone with plant remains Black carbonaceous sandy shale Calcareous grey sandstone with fragments of encrinites and shells Black carbonaceous sandy shale Bluish shale with fakes and flattened easts of Productus . . B Tough limestone band, consisting of comminuted fragments of shells and encrinites, very variable in thickness from 6 in. to Soft dark blue calcareous shale with encrinites and Syringopora . . Nodular hard limestone, very fossiliferous. Corals, brachiopods (Orthids, Didasma, Spirifer, Productus) and small lamellibranchs. The limestone is in places like a breccia in appearance — base not seen . . . . . . . . . . . . 6 to 8 49 6 The three bottom beds probably represent the Long Craig Middle and Upper Limestones. The quarry to the north of the road shows that the beds above the lowest limestone pass laterally into about 20 ft. of black carbonaceous shale with pea-like galls and thin seams of clay-band ironstone. The lowest limestone of the above section is also seen in the banks of the Tyne at the bend near Salton Hall, where about 20 ft. of lime- stone are exposed and have been formerly quarried. The base of the higher limestone and calcareous shales (Skateraw Middle and Upper) is also seen in the banks of the Tyne at Spilmersford Bridge, the band with Saccammina carteri being exposed. The upper parts of this lime- stone have been formerly extensively quarried at Spilmersford ; the bottom of the limestone is not reached in the quarry, but 20 ft. of limestone and calcareous shale with a thick massive bed of limestone at the base are exposed, and the dark inky ooloured shale band is also seen. The limestone is fossiliferous, containing encrinites, small corals, and trilobites. The limestone formerly quarried in East Salton Wood, close to East Salton, is also probably the same ; about 15 ft. of limestone and calcareous shale with Productus punctatus (Mart.) are exposed. 4 1 6 6 1 6 3 3 1 6 144 Carboniferous Limestone Series. In the quarry at Blance Bridge, about three-quarters of a mile east from East Salton, on the road to GifEord, a nodular pale grey limestone, with numerous enorinites, Productus and Lithostrotion, is one of the lower limestones (Long Craig limestone), and probably the same as the lowest exposed in the East Salton quarries. Limestone and black shale are exposed at West Blance, but their position is un- certain. At Law Quarry, half a mile south-west of East Salton, the following section was observed : — Ft. in. A Pale grey limestone full of enorinites, the base consisting of a band of Lithostrotion ; top not seen . . . . . . ..30 Blue shale . . . . . . . . . . ..10 White and red sandstones, bottom not seen . . more than 20 It is probable that this limestone is the lowest in the sequence at Aberlady ( = Long Craig Middle Limestone). At Salton Hall the Lower Limestone group crosses the Humbie and Tyne Waters, and continues its south-west course. Limestone, shales, and sandstones are seen in the new railway cutting near Lampock Wells, but the sections are obscure. A nodular very fossiliferous limestone containing Lithostrotion occurs in the Kinchie Burn below the distillery, and no doubt represents one of the Long Craig limestones, and the quarries at a higher level close by expose the thick upper limestone with the " Saccammina band " ( = Skateraw Middle). The intermediate hard limestone ( = Skateraw Lower), is also met with in the burn immediately above the bridge near the distillery. The surface between Glenkinchie and Muttonhole is swathed in drift, but the quarries, at Lampland, Peaston and north of Dodridge Law, show that the strike gradually becomes more westerly as we proceed south-westwards. The. sections in these quarries are as follows : — Ft. in. Lampland Quarry — Limestone in one bed, very ferruginous, and with numerous en- orinites, also corals, brachiopods, lamellibranchs, trilobites, poly- zoa and other fossils . . . . . . . . Pale blue calcareous shale with Nucula, and weathering with » white powdery surface . . . . . . from 3 to Inky coloured shale weathering with a white surface Pale blue calcareous shale Inky coloured shale with Nucula and Productus ("Very hard pinkish ferruginous limestone with large encrinite | stems . . j Limestone band with Saccammina carteri [Dark blue hard nodular limestone, top only seen . . . . — The above beds represent the Skateraw Middle and Upper Lime- stones. Peaston Quarry — Ft. in. Grey compact ferruginous limestone consisting largely of enorinites . . 4 Calcareous shale . . . . . . . . . . ..10 Calmy, well-bedded, dark bluish hard limestone, rather lenticular and with thin shaly partings. Large simple corals, Productus and en- orinites ; base not reached . . . . . . . . at least 12 5 1 3 6 10 4 1 Ft. in. 6 2 6 6 Aberlady to Pathhead. ; 145 It is not certain to which horizon this limestone belongs. It is possibly higher than the Skateraw beds. The limestone in the quarry north of Dodridge Law resembles that of Peaston, and is at least 12 ft. thick. It is very fossiliferous, containing numerous encrinites, also sponges, corals, brachiopods, lamellibranchs, etc. Limestone has recently been worked south of Muttonhole in a large quarry extending about half a mile along the crop ; the section exposed is as follows : — Soft calcareous shale weathering with a white powdery surface . . Inky coloured shale {Soft calmy limestone or calcareous shale Hard dark blue ferruginous limestone weathering in a nodular fashion. Saccammina carteri occurs near the top in lenticular masses . . . . . . . . . . . . at least 8 The above beds represent the Skateraw Middle Limestone and some of the higher bands. Fossils are abundant in this quarry. Amongst them are encrinites, gasteropods, brachiopods, lamellibranchs, polyzoa and corals. Cone- in-cone structure occurs in bands of limestone in this quarry. Quarries have also been worked south-east of Crichton, where about 20 ft. of hard concretionary limestone are seen, but neither top nor bottom. Among the fossils met with was Litho- strotion junceum (Flem.). There are also other corals and many encrinites and brachiopods. The limestone resembles the second limestone seen in the Tyne Water in one -inch map 32 ( = Long Craig Upper). The tracking of the outcrops of the limestones described has been rendered possible, rather by a combination of the palseontological and physical evidence, than by true zoning in the strict palseonto- logical sense. The abundance of compound corals in the Long Craig Middle Limestone and the nodular dolomitic character of the Longcraig Upper Limestone, and the strong evidence of shallow water conditions in the beds that accompany them, have been of service in this task. The recognition of the Skateraw Middle Limestone has been greatly facilitated owing to the wide extent of the band of Saccam- mina carteri, which has been traced from Dunbar nearly as far west as the Tyne Water. The great thickness of limestone and shale from the Skateraw Middle up to the Skateraw Upper Limestone mark this horizon as a prolonged phase of rather deeper water conditions, or of greater distance from the source of terrigenous sediment. The Skateraw Middle Limestone is separated from the Skateraw Upper band by a mass of shale in the region of Dunbar, and at Aberlady the former limestone is not of great thickness, and the band of Saccam- mina carteri is absent. On passing southward, the intervening shale becomes interleaved with limestone, and the whole passes gradually into limestone with subsidiary bands of calcareous shale. Some of these bands have a peculiar inky colour, and are character- istic of this shale -limestone phase, being traceable over wide areas south of the Tyne, and into the adjoining one-inch map 32. c. B. C. 10 146 Cwrbemferotus Limestone Series. LENNOXLOVE OUTLIER. ; A limestone outlier, about half a mile long and a quarter of a mile broad, is found at Lennoxlove, about a mile south of Haddington. Its isolation is simply due to denudation of the beds which formerly connected it with the main outcrop. This limestone was formerly extensively quarried, and has also been more recently worked for road-metal. It is a grey well-bedded fossiliferous limestone at least 15 ft. thick. No limestone occurs below it for more than 300 ft., as has been already shown in describing the Calciferous Sandstone series.* e. b. b. (.,. * The exposure of limestone at Kidlaw, formerly considered an outlier, has been shown to be a glacially transported mass, and will l>e referred to in Chap. XVX The mass of contorted limestone at Marl Law Quarry, Crichton Dean, is also probably a transported mass, and the lower boundary of the limestone has been drawn to exclude this quarry. These transported masses have apparently been derived not from one of the lowest limestones, but from one of those higher in the series. CHAPTER XII. CARBONIFEROUS LIMESTONE SERIES.— (Continued) Edge Coal Group. introduction. The group about to be described makes up nearly all the East Lothian coalfield, which differs considerably in structure from the Mid-Lothian coalfield to the west. It presents the character of a shallow basin, with flat or gently undulating strata, and is separated from the deeper Mid-Lothian basin by the Roman Camp anticline, the crest of which runs north and south, and lies just a little to the west of the western margin of one-inch map 33. This anticline brings to the surface beds belonging to the Lower Limestone group, while the basin itself is mostly occupied by the Edge Coal group, and by beds stratigraphically equivalent to those known elsewhere as the Upper Limestone group, though the limestones, as we shall see later on, have very seldom been proved. The eastern boundary of the basin is formed by the outcrop of the Lower Limestone group. Within this shallow basin are several minor undulations, which, in combination with the general flatness of the seams, render the outcrops very difficult to trace. Often the contour of the country has as much to do with determining the outcrops as the dips of the seams themselves. Fig. 8, shown on next page, has been drawn to represent the general vertical section of the Edge Coal group of the basin. TRANENT DISTRICT. The following table gives a general section of the coal seams and intermediate strata belonging to the Edge Coal group in the northern part of the East Lothian basin : — Ft. in. Horizon of Index Limestone . . . . . . . . . . — Strata including some quarried sandstones and one or two thin coals, about . . . . . . . . . . 60 Great Seam . . . . . . . . . . .. 5 ft. to 7 Strata about . . . . . . . . . . 70 Splint Coal .. .. .. .. .. ... 4 it. to 5 Strata about . . . . . . . . . . 18 Parrot or Gas Coal . . . . . . . . 1 ft. 6 ins. to 2 Strata about . . . . . . . . . . 15 Three-Feet Coal . . . . . . .'. . . 2ft. to .2 6 Strata .. .. .. .. .. .. . . 18 Four-Feet Coal .. .. .. .. .. ..3 Strata with sandstone and shale and one or two thin coals . . 80 147 148 Carboniferous Limestone Series. Black-Band Ironstone (where present) Strata Five-Feet Coal Strata with one or more thin coals Penston Splint Strata about Bough or Under Coal The distance from the Rough or Under Coal to the top of the Lower Limestone series is very uncertain, but cannot be more than about 20 fms. The upper two-thirds of the Edge Coal group in this district contain, Ft. in. 1 • • 15 1 ft. 6 ins. to 3 6 70 3 10 2 6 Horizon of Index Limestone Great Seam Splint Coal Parrot Coal Three-Feet Coal Four-Feet Coal B. B. Ironstone Five-Feet Coal P. Splint Coal Bough Coal Hauohielin Limestone x o z II I'- ll. o o u _i <: o FMS. 10 FMS 20 FMS. 30 FMS. 40 FMS. 50 FMS. 60 FMS. - 70 FMS. J 80 FMS. Fig. 8.— Diagram of the General Vertical Section of the Edge Coal Group of the East Lothian Basin. as we shall see, a very well marked series of coals, which can readily be identified with one another from colliery to colliery. The lowest of these is the Five-Feet Seam (see Fig. 8). The relations to one another of the coals beneath the Five-Feet Seam are not so perfectly known. Edge Coal Group. 149 The lowest coal seam known in the district is the " Under Diamond Coal " which has been proved close to the Macmerry railway, just where it enters the present one-inch map. This has been shown by a bore to be 1 ft. 10 ins. in thickness. It lies three fathoms above a band of limestone, and at least 18 fms. under any other workable coal. It is thus, in all probability, the same as the Parrot Coal of Newbattle and the Hauchielin Coal of the Pathhead district, while it also corre- sponds with Diamond No. 2 of the former Dolphingstone Colliery, situated just outside the limits of the map.* Apart from this locality, the Hauchielin is not known to occur in the district being described. Along the east side of the basin near Penston two coals occur close to one another about 12 fms. below the Five-Feet position. The upper of these is known as the Penston Splint, and the lower, which is about two fathoms below it, is here known simply as the Under Coal. These are the same as the coals known further south as the Splint and Rough, and it is probable that one or both of them may correspond with the Kailblades of Newbattle. Two coals were met with in a bore put down by the late Mr. McMillan at Fleets Colliery, near North Elphingstone. These occur respectively about 10 and 14 fms. below the Five-Feet, and are probably the same as the two coals last referred to. The upper coal is now being opened up. A coal named the Diamond was formerly wrought close to the position of the present Macmerry railway, and just on the margin of one-inch map 33. This coal is at least 18 fms. above the Under Diamond Coal before referred to, and is probably one of the same two coals, and the same also as the Kailblades of Newbattle and the Diamond No. 1 of the old Dolphingstone Colliery. A coal found five fathoms below the Five-Feet at the Tranent Collieries is probably the same as the Beggar Seam of Prestongrange and Dolphingstone, but it is not at present of importance. In the upper group of coals before referred to, the highest workable coal, and the thickest coal in the Edge Coal group of this district, is the Great Seam. It corresponds with the Great Seam of the Mid- Lothian basin, and is probably about ten fathoms below the horizon of the Index Limestone. The lowest member of this group, named the Five-Feet Seam, has certain characters which show that it is the same seam as the Jewel of Prestongrange, and the Five-Feet Seam of Wallyford and Carberry (one-inch map 32). The Pan wood Coal of the eastern part of the basin was once thought to be distinct from the Five-Feet, but it seems now to be really the same. Between these two very well-marked coals is a group of four, which, although they can be followed from colliery to colliery throughout this district, cannot be correlated with so much certainty with the coals of the adjoining basin. Their names in ascending order are the Four-Feet Coal, the Three-Feet Coal, the Parrot or Gas Coal, and the Splint. They generally occur pretty close together, the Four-Feet Coal being in some cases only seven fathoms below the Splint ; while they are separated by greater intervals from the Great Seam above and from the underlying Five-Feet Seam. Of the four, the Four- * See explanation of one-inch map 32. 150 CarboniferoWs' Limestone Series. Feet Seam and the Splint are in general the thickest, and are now the most widely worked ; the Parrot was formerly extensively worked" for the sake of the Gas Coal which it contains. A black-band iron- stone occurs in one or two localities a short distance above the Five' Feet Seam, and will be referred to more fully in the chapter on Economics. The outcrop of the Great Seam after runnng out to sea opposite Northfield Colliery, situated just outside the limits of the map, is brought in again on the foreshore by a number of small faults, and bends inland at the eastern extremity of Prestonpans. This seam has been worked at Preston Links Colliery, along with the underlying Jewel or Five-Feet Coal : the seaward boundary of the workings was till recently formed by the whinstone dyke which runs along the foreshore and out to sea just west of Cockenzie Harbour, but this dyke has now been pierced, and the Great Seam is found to dip gently out to sea on the northern side. A short distance to the south of the dyfee the workings are interrupted by an east and west fault, with about 40 fms. downthrow on the northern side, which is well exposed on the foreshore. , Besides the Great Seam and the Five-Feet Seam already mentioned,, there are three intermediate seams which have been formerly worked at this colliery, partly on account of beds of fireclay which occur under each of them. These are known as the Upper Clay Seam, the Fire Clay Seam, and the Under Clay Seam. The suggested correlation of these seams with those occurring at Wallyford in the north-eastern part of the Mid-Lothian coal-field, and also with the well-known seams occurring further inland in the East Lothian coal-field, is given in the accompanying table : — Wallyford. Northfield. Preston Links. East Lothian. Great Seam Great Seam Great Seam Great Seam Jewel • Parrot Rough Diver Clay Three-Feet Upper Clay Fireclay Splint Parrot or else Three-Feet Five-Feet Jewel Under Clay Jewel Four-Feet Five-Feet It will be seen that according to this correlation the Wallyford Jewel Coal corresponds to the Splint Coal of East Lothian. This opinion has been formed after drawing up sections of the strata at all the intermediate collieries in graphic form, and comparing them, but the evidence is not quite conclusive. South of Preston Links the outcrop of the Great Seam is not accur- ately known, but it must swing inland somewhat abruptly. The section in the cutting made for the mineral railway to Preston Links Colliery shows that the Roslin Sandstone series must exist somewhat to the north of Thorntree Mains, and there is evidence to suggest that it extends southward nearly as far as Bankton. On the other hand several small collieries south of Thorntree Mains formerly worked Edge Coal Group. 151 a coal which was called the Spliat. On the whole, it seems most likely that this was really the Splint of the Edge Coal group, though this supposition raises a difficulty, as these collieries were situated quite close to the spot where, as we have mentioned, there seems evidence of the presence of Roslin Sandstone, and there would be no room for the intervening Upper Limestone group to crop out. The solution of the difficulty may He in the existence of a large fault with downthrow to the north-west, running north-eastward from Bankton, and keeping to the north of Thorntree Mains. A fault running in the right direction has been proved from Bankton Colliery (situated north-east of Bankton House), but the amount of its downthrow is not known, and the mapping of this district must not be regarded as final. On the east side of this fault, there seems to be an area from which the Great Seam is " off," although, as we have stated, a coal called the Splint was wrought. The outcrop of the Great Seam describes a somewhat sinuous course to the north of Tranent, and then turns and runs in a generally southward direction to a point west of Elphing- stone village. The outcrops of several of the lower seams no doubt run parallel to it in this part of its course and farther to the west, but they are ill-defined and are not shown on the map except in particular localities. At the Tranent Collieries, situated to the south and east of Tranent, the seams have all been worked down to the Five-Feet Coal. The most notable feature at these collieries is the presence of two faults forming a trough-like depression. These occur to the east of Tranent, and run somewhat east of south. The one to the west has a down- throw of 20 fms. to the east. The more easterly one has a westerly downthrow of 40 fms., and continues a considerable distance to the south. At Fleets Colliery, situated about a quarter of a mile north-east of North Elphingstone, all the coal seams are present from the Great Seam down to the Five-Feet. Reference has been made already to the two seams which have been proved beneath the level of the Five-Feet Seam. South of Fleets Pit, and just north of the village of Elphingstone, the strata are thrown down, by two east and west faults, into a trough-like depression within which the coal seams are 80 ft. below the level at which they occur on either side. West of Elphingstone the Great Seam is very well exposed in some old workings in a small plantation called the Fufiets Wood. From this point the outcrop runs in an easterly direction south of Elphing- stone, and then north-west. The Splint, and in one place the Five- Feet Coal (here called the Triping) also crop out between Elphingstone and the Macmerry railway. At Elphingstone Colliery (Howden Pit, situated half a mile east of South Elphingstone) the Four-Feet Seam is worked, while at the Cockham Pit of the Ormiston Coal Company, situated half a mile south-west of Buxley, work is carried on both in the Splint and in the Four-Feet. Continuing its course to the north-west, the outcrop of the Great Seam runs past Buxley up against the continuation of the more easterly of the two faults referred to as being met with in the Tranent Collieries. This fault cuts it out for about half a mile, but it is 152 Carboniferous Limestone Series. finally brought in by a smaller fault somewhat to the east of Kingslaw. From thence it continues to neaT Rigganhead, where it was worked in the old Garnet Pit. Here its course is interrupted by another of these curious trough-forming double faults, the depth of the trough in this case being about 25 fins. On the other side of the trough it continues its course towards the shore, which it reaches about three- quarters of a mile east of Port Seton Harbour. Near this latter point it is known to be about five and a half feet in thickness, and to lie about 14 fms. beneath the Index Limestone. On the eastern side of Elphingstone and Tranent the outcrops of the lower seams down to the Four-Feet probably lie east of that of the Great Seam — between the latter, in fact, and that of the Panwood or Five-Feet Seam — but it has not been found possible to lay them down on the map. In the district lying just south of Macmerry, the two seams known farther south as the Splint and Rough, but here better as the Splint Coal and the Under Coal, have been extensively worked in former times. A coal in a somewhat higher position was also worked in this localitv, and was known under the name of the Panwood Coal. Although it is an inferior seam, there seems reason, as we have said, to suppose that this coal is really the same as the Five-Feet. Close to Penston and Macmerry are several abandoned ironstone mines, which worked what was known as the Penston Ironstone. This ironstone occurs about 15 ft. above the Panwood Coal, and it is interesting to note that an ironstone was worked a short distance above the Jewel or Five-Feet Coal at the now abandoned Dolphing- stone Colliery (west of Tranent, on the eastern margin of one-inch map 32). The outcrops of the Splint and Rough Coals are repre- sented on the map by a single line ; this line and the outcrop of the Panwood seam run for some distance roughly parallel to the outcrop of the underlying limestone group. The Panwood Coal is 1 ft. 6 ins. thick at Penston, and is about 21 fms. above the Splint and Rough Coals. Just north of Macmerry the Penston Splint is worked from the Montfair Pit ; the Under Coal, which lies two fathoms below it, has not been worked here till quite recently. The Penston Ironstone does not occur at this pit, and has apparently died out. At least 29 fms. of strara have been bored through above the Splint Coal without passing through any ironstone or thick coal, and it is certain that the positions both of the Five-Feet Seam and of the accompany- ing ironstone must occur within this interval. The former is probably represented by a thin seam which occurs in the bore section. It is possible that some of the faults which are known to exist at St. Germains continue further to the east, and account for the fact that the Splint and Under Coals have not been proved within a mile to the south of the dolerite dyke that runs past Cantyhall. On the north side of this dyke their outcrop is again shown, and it runs out to sea about a mile and a half to the east of Port Seton. A fuller description of the characters of coals and ironstone, etc., occurring in this district, will be found in the chapter on Economics. E. M. A. Ft. in. 80 4 75 4 10 3 30 3 Edge Coal Group. 153 ORMISTON TO PATHHEAD. This area comprises the ground south of the Monktonhall Railway, and extends as far east as Wester Pencaitland. It stretches south to the outcrop of the Lower Limestone group, and on the west is bounded by the edge of the map. Rock exposures are scarce and small owing to the wide spread of drift, but we have been able to draw up the following generalised section from the mining information generously supplied by the owners and managers of the collieries : — Strata, mostly sandstones, about Great Seam Strata, chiefly sandstones, about Tranent Splint Strata . . . . . . . . • ■ from 8 ft. to Parrot-Rough, usually with thin seam of Parrot . . from 1\ ft. to Strata with two or three thin coals, one of which probably repre- sents the " Three-Feet Coal," about Four-Feet Coal, often with thin seam of Parrot . . from 2 ft. to Strata, upper part mostly sandstones ; thin coals and ironstones below. One of the latter was formerly worked as the " Pan- wood Ironstone ". . .. .. .. .. 80 Five-Feet Coal (probably represents the Panwood Coal formerly worked near Preston Hall) . . . . from 2 ft. to 4 Strata, upper part mostly sandstone, but with thin coals below, about .. .. ... .. .. ■• .. 60 Splint and Rough Coals, averaging 2 ft. 6 in. each, with 8 to 10 ft. of strata between .. .. .. .. .. 15 Strata, with sandstones above and blaes and ironstones below, about .. .. .. .. .. .. .. 60 Parrot (Arniston) or Hauchfelin, formerly worked near Pathhead, about . . . . . . . . . . . . ..16 Strata . . . . . . . . . . . . . . 34 Limestone The crops of these coals as now drawn differ slightly from those on the earlier edition, and additional crops, chiefly of coals above the position of the Panwood Ironstone, have been added from infor- mation acquired from recent bores and workings. The coals chiefly worked now are the Splint and Rough at the Tyneside pits, Ormiston Colliery. A higher seam, the Four-Feet Coal, is worked at the Ormiston Station and Limeylands Colliery by the Ormiston Coal Company. The Great Seam is the highest workable coal, and occupies a comparatively limited area to the south-east of Ormiston. A pit sinking to this coal has lately been in progress near Red Row, south-east of Ormiston ; but we do not know whether this seam, or others underlying it, are being worked.* The Hauchielin Coal. — This coal is the lowest known coal in the basin, and its position is about 40 ft. above the top of the Lower Limestone group. It is, however, not continuous as a workable seam, and is only known at Pathhead and Preston Hall, at the southern extremity of the coalfield, where it was formerly wrought. This seam has been proved to be the same as the Parrot Coal of Edgehead, Arniston, and Newbattle, by tracing its outcrop from Vogrie, in the adjoining map 32, across the River Tyne, at Ford, to Pathhead, and * The Great Seam is now being worked from this pit. 154 Carboniferous Limestone Series. by taking into consideration the distance it lies above the limestones. The Parrot, however, which makes the seam so valuable at the former collieries, does not continue to the east across the Tyne, where the seam becomes an ordinary " rough " coal from 15 ins. to 18 ins. thick. The following section gives its thickness and position above the lower limestones as formerly proved in a bore on the west side of the Tyne near Ford : — Section from the Hauchielin or Parrot Coal down to the Lower Limestone near Ford. Shale (blaes) . . Hauchielin (Coal (hard) or Parrot] Coal (" Parrot ") Coal [Coal (dross) Fakes White sandstone Soft parting Sandstone and shale Sandstone Shale (blaes) . . Limestone It will be noticed that the distance between the limestone and the coal is here 34 ft. The Tranent Splint and Parrot Rough Coals occupy a limited area to the south of Ormiston, and also form a small separate basin at Limeylands. These coals have also been proved to He beneath the surface near Oxenford Mains, where they must also form a separate basin, elongated in a north and south direction, the limits of which have not been accurately defined. The Great Seam forms a small basin to the south-east of Ormiston, not exceeding half a square mile in extent, which is truncated by a fault on its N.E. side. This fault is a continuation of the one drawn on the former map from Huntlaw in a N.W. direction for more than a mile towards Ormiston. Its throw in the workings of the Huntlaw Colliery is 33 fms., the Great Seam on the south-west side of the Fault being brought against strata overlying the Pencaitland Splint. C. B. C. Ft. in. 3 11 6 6 4 5 5 5 3 9 1 12 10 6 1 6 Upper Limestone Group. During the original survey Mr. Howell mapped two thin limestones on the coast east of Port Seton, referring them to the Upper Limestone group. The correlation has been confirmed in the recent revision, and additional evidence has been gathered regarding the extension of the group inland. In the neighbourhood of Port Seton the group is overlain by the Millstone Grit and Coal-measures, so that the full sequence is preserved (see Sketch Map, Chap. XIII.). The best exposure is that of the shore section * east of the village ; four lime- * Already described in a paper by E. B. Bailey andD. Tait, " On the Occurrence of True Coal-Measures at Port Seton, East Lothian," Trans. Qeol. Soc. Edin., 1905^ vol. viii. pp. 352-355. Upper Limestone 6frewp. 155 stones are exposed, the loweBt of which has been proved by miming operations to lie about 14 fms. above the Great Seam, so that it is undoubtedly the Index Limestone, that is, the basement bed of the gtoup. The following vertical section has been compiled from measure- ments made along the shore : — No. 6 or Castlecary Limestone Sandstone with Stigmaria Fossiliferous sandy shale Sandstone Various strata Parrot Coal Gannister. . Coal Various strata Sandstone . . Shale No. 5 or Arden Limestone { L ™y shale Various strata The Extra Limestone Various strata Coal Various strata Coal streak Shale Sandstone Various strata Sandstone Shale No. 4 or Index Limestone from 4 in. to Ft. in. 2 6 I 4 10 41 7 1 2 2 12 5 44 24 1 8 32 9 9 17 11 6 7 8 35 19 2 48 5 9 1 2 Total 316 8 The Extra Limestone of the above section is characterised by an abundance of Productus latissimus J. Sow., and it is noteworthy that an " extra " limestone, not improbably the same bed, which is exposed in the Niddrie and Gilmerton railway cuttings, Mid-Lothian, is also crowded with this species. It may be noticed that the whole group is greatly attenuated in comparison with its development in the northern portion of Mid- Lothian ; thus at Niddrie, only six miles to the west, 1070 ft. of beds intervene between the Index and Castlecary Limestones, as compared with 316 ft. at Port Seton. E. B. b. Inland, evidence has been obtained of the existence of two thin bands of limestone, some distance above the Great Seam, one of which, known familiarly as " Wattie's Toe," occurs from 5 to 10 fms. above the Great Seam,* and may be the Index Limestone. The other appears at a higher level, probably about 30 fms. above the Great Seam, in the shaft of Fleets Pit, about a quarter of a mile north-east of North Elphingstone, but the horizon of this limestone is uncertain. It is thus probable that part of the area to the south and east of Tranent, shown on the map as above the level of the Great Seam, is occupied by strata of the Upper Limestone group. A section of strata of the same age is exposed in the cutting * This information has been kindly supplied by Mr. Henderson, Mineral Boring Contractor, Edinburgh. 156 Carboniferous Limestone Series. of the railway to Preston Links Colliery, half a mile east by north of Prestonpans. None of the limestones are, however, actually seen. It is likely that this group continues, forming a strip on the west side of the area of Millstone Grit shown on the map to the east of Prestonpans, but the geology of the district is very obscure. Strata of the Upper Limestone group also occur on the shore between Preston- pans and Cockenzie, but here, also, no limestones are visible. No. 5 Limestone (the Arden) is probably cut out by a fault, while it is possible that the Index Limestone is absent in this locality. e. m. a. CHAPTER XIII. MILLSTONE GRIT AND COAL-MEASURES.* Millstone Grit. The Millstone Grit or Roslin Sandstone series is here taken to include all the beds which come between the Castlecary Limestone, at the base, and the top of the thick massive sandstone on which the eastern wall of the Port Seton Harbour is built. The lower limit is certainly the same as in Mid-Lothian, and the upper one is probably approximately so. In East Lothian the series is only found in one locality, sur- rounding the Coal-measures of the little Port Seton basin (Fig. 9). It is well exposed along the coast on either side of this syncline. The details of the section as measured on the eastern side of the harbour are given below in a condensed form : — 1. Sandstone . . 2. Various strata with Upper Carboniferous plants 3. Sandstone . . 4. Sandstone and red mottled fireclays with thin coals towards the top 5. Shale with Upper Carboniferous plants on top and Produoti below 6. Mottled fireclay or marl 7. Sandstone 8. Red nodular calcareous ironstone with marine fossils 9. Various strata down to the top of the No. 6 Limestone Ft. 44 28 104 84 15 8 57 2 160 502 In lithological character the Port Seton section resembles the type sections of the Roslin Sandstone series in Mid-Lothian. The thick sandstone (No. 3 in the foregoing section) contains large pebbles of white and yellow vein quartz, well rounded and distributed in a most sporadic manner, while the mottled red, white, and blue fireclays so typical of the group in Mid-Lothian are finely represented. A peculiar interest attaches to the fossil contents of this Roslin Sandstone since, owing to the researches of Mr. Kidston f and Dr. Traquair.f it is now known that somewhere within its limits a marked palseontological break, both as regards the flora and the fish fauna, divides the Carboniferous System palaeontologically into two divisions. Mr. Kidston has determined the plants which have been obtained from this section, and the evidence proves that Lower Coal-measure forms (Upper Carboniferous) extend far down into the Roslin Sand- stone series. Unfortunately no recognisable plants were obtained * This chapter is in the main based upon a paper by E. B. Bailey and D. Tait, " On the Occurrence of True Coal Measures at Port Seton," Trans. Geol. Soc. Edin., 1905, vol. viii. p. 351. t Sum. of Prog. Geol. Survey for 1902 (1903), p. 118. X " On the Distribution of Fossil Fish Remains in the Carboniferous Rocks of the Edinburgh District," Trans. Roy. Soc. Edin., 1903, vol. xl. p. 707. 167 158 Millstone Grit and Coal-Measures. Millstone Grit and Coal-Measures. 159 from the lower beds of the group, and no fish remains were found in any part of the section. The recognition of two marine bands (Nos. 5 and 8 in the section) Is also a point of great interest in connection with what may be termed the natural history of the group, and also because there is reason to beEeve that the bands may be of great value as stratigraphical horizons. The lower of the two bands is a red calcareous ironstone of a peculiar nodular character, and contains Productus and other thoroughly marine forms. The upper marine band occurs 65 ft. higher up in the sequence, and is a dark reddish shale with ironstone nodules, in the upper fissile part of which two pinnules of Alethopteris lonchitica (Schloth.) (?) and a specimen of Cordaites have been obtained. On the evidence of these plants Mr. Kidston places this bed in the Upper Carboniferous series. The two marine beds are seen in both limbs of the syncline on the east and on the west side of the harbour respectively, and on the west the section ends a short distance below them. Another fossil-bed was found on the east side of the harbour about nine feet below the highest thick sandstone (No. 1 in section) ; it yielded the following Upper Carboniferous plants : — Alethopteris lonchitica (Schloth.). Mariopteris muricata (Schloth.). Neuropteris gigantea (Stemb.). Sphenophyllum cuneifohum (Stemb.). Calamites sp. On the other side of the syncline in the western division of the harbour, and approximately on the same horizon, lamellibranchs of estuarine type occur, viz. : — Anthracomya williamsoni (Brown). Naiadites modiolaris (J. de C. Sow.). e. b. b. The Roslin Sandstone series probably extends southwards from the Port Seton basin to the neighbourhood of Bankton. It appears to be bounded on the east by a large fault with downthrow to the west, dimini sh ing rapidly northwards, which brings the series in contact with strata of the Edge Coal group. e. m. a. Lower Coal-Measures. True Coal-measures, overlying the Millstone Grit, have a very restricted distribution in East Lothian, being confined to the little basin at Port Seton, on the shores of the Firth of Forth. This basin is only 200 yds. across from east to west. The following section is based upon measurements made in the harbour itself : — Ft. in. Sandstone .. .. .. .. .. . . (?) Coal . . . . . . . . . . . . 6 4 Various strata . . . . . . . . . . . . 12 10 Coal . . . . . . . . . . ..04 Carry forward 19 6 160 Millstone Grit and Coal-Measures. Ft. in. Brought forward 19 6 Various strata . . . . . . . . ■ - . . 6 6 Coal .. .. .. .. .. -.7 Various strata . . . . . . . . . . . . 23 Foul coal . . . . . . . . . . . . 5 Various strata . . . . . . . . . . . . 23 Carbonicola shale . . . . . . . . . . 4 Coal with parrot . . . . . . . . . . 1 Various strata . . . . . . . . . . . . 44 133 On the north-eastern side, a few of the lowest beds belonging to this division are exposed outside the harbour ; one of these is a tough ferruginous sandstone rib which crops out on the seaward side of the eastern breakwater, and has yielded the following Upper Carboniferous plants : — Neuropteris heterophylla Brongt. Spiropteris sp. Cyclopteroid pinnule. Annularia radiata Brongt. Sphenophyllum cuneifolium (Sternb.). Cordaites principalis (Germar.). The shaly beds in the western division of the harbour, which also lie immediately below the Carbonicola bed, have furnished the following forms : — Alethopteris lonchitica (Schloth.). Mariopteris muricata (Schloth.). Calamites cistii Brongt. ,, suckowii Brongt. ,, undulatus (Sternb.). Sphenophyllum cuneifolium (Sternb.). Cordaites principalis (Germar.). Stigmaria ficoides (Sternb.), var. undulata (Gopp.). The specimens collected from the Carbonicola bed were examined by Dr. Wheelton Hind, who finds that they all belong to one species — C. robusta (J. de C. Sow.). The shells are usually preserved in iron- stone, and often have both valves in position. Attached to one of the specimens there was found a tube of the little annelid Spirorbis. Viewed from a stratigraphical standpoint this band merits special attention, for in the Mid-Lothian basin a similar Carbonicola bed is found near the base of the Coal-measures. It has been recorded from several localities by Milne Home,* including Joppa Shore, while additional evidence of its wide extent has been obtained during the recent revision. "f It is right to state that if we assume that the Carbonicola shale found at Port Seton belongs to the same horizon as the above, we must recognise that certain important coals occurring below it at Joppa have disappeared before reaching Port Seton. * Milne (Home), "The Coal-Fields of the Lothians," 1839, p. 18. f C. T. Clough, Sum. of Prog. Oeol. Survey for 1903 (1904), p. 100. Lower Coal- Measures. 161 In the east division of the harbour, in strata overlying the Carboni- cola bed, the following plants were collected : — Sphenopteris acuta Brongt. Calamites ramosus (Artis.). Calamocladus equisetiformis (Schloth.). It will be seen, then, that both in the occurrence of Lower Coal- measure plants and of the lamellibranch — Carbonicola robusta — the evidence of the presence of Upper Carboniferous strata at Port Seton is conclusive. It ought to be borne in mind, as already indicated, that Upper Carboniferous plants of Lower Coal-measure age occur well below the line which has here been taken as the base of the Coal- measures. In this description both palseontological and lithological evidence has been employed to bring the classification of the Carboni- ferous rocks at Port Seton into line with that established, chiefly by Mr. Howell,* for Mid-Lothian. e. b. b. * " The Geology of the Neighbourhood of Edinburgh,'' Hem. Geol. Survey, 1861. II CHAPTER XIV. INTRUSIVE IGNEOUS ROCKS LATER THAN THE COAL- MEASURES. In previous chapters it has been shown that the county of East Lothian possessed more than one active volcanic centre during the earlier portion of the Lower Carboniferous epoch. Following upon this came a long period of quiescence which affected the whole of Central Scotland, although its inception was delayed in some of the western districts until after the commencement of Coal-measure times. When igneous activity once again manifested itself it was in a manner quite distinct from that of the earlier eruptions, and led to the injection of a suite of dykes and sills in connection with the earth movements which brought the Carboniferous age to a close.* The surface distribution of the sills at the present time is more limited than that of the dykes, and in Haddingtonshire only the latter are represented. They occur chiefly between Port Seton and Dunbar, and have the general east and west trend which characterises the majority of the dykes of this period throughout the southern part of Scotland, and many of the faults also. These east and west dykes are usually of considerable breadth, amounting sometimes to as much as 30 yds. ; they are coarse in texture, rudely jointed and apt to weather to a ferruginous sand. Petrographically, they are entirely removed from the products of the early volcanic phase, and do not belong to any branch of the alkali family of rocks. They may be briefly described as olivine-free subophitic dolerites, consisting essentially of plagioclase felspar and augite, with abundant titaniferous magnetite and a mesostasis, some- times of glass, sometimes of micropegmatite. They belong to the quartz dolerite group, the less crystallised varieties being tholeiites. Hypersthene not infrequently accompanies the monoclinic pyroxene. The latter does not show the strong purple tint characteristic of the augites of the basic intrusions of the volcanic period, and this, combined with the absence of analcite and olivine, is generally a sufficient distinc- tion even where neither micropegmatite nor quartz can be recognised. For further details concerning the petrology of this interesting group of rocks, the reader may refer to Dr. Falconer's f exhaustive paper on their representatives in the vicinity of Linlithgow, or to Dr. Flett's account in the Geological Survey Memoir on the Edinburgh District. The east and west dykes of Haddingtonshire run generally in a direction somewhat north of east. Two important examples are * For a discussion of the evidence pointing to the Pernio-Carboniferous age of the intrusions referred to, cf. G. W. Grabham in the second edition of the Geological Survey Memoir on the Edinburgh Bistriot. f " The Igneous Geology of the Bathgate and Linlithgow Hills," pt. ii., Petro- graphy, Trans. Roy. Soc. Edin., 1906, vol. xlv. p. 133. 162 Dolerite Dykes. 163 seen near Prestonpans and Port Seton : in the latter case the dyke may be seen in clear section traversing the little basin of Lower Coal- measures which occupies the site of the harbour ; the sandstones and shales are here greatly indurated at their contact with the dolerite, and the coal seams are " burnt." The Port Seton dyke can only be traced a few yards eastwards from the harbour, when it tapers out, and no continuation can be recognised along the direct line of its strike to the east. On the other hand, another parallel dyke, forming the boundary of the foreshore to the north-east, suddenly comes into existence at this juncture and can be traced through the Dalskelly Crags to the railway at Spittal. No doubt the two dykes should be regarded as a single intrusion. Discontinuity of outcrop seems to be rather a characteristic of the east and west dolerite dykes of the county. Proceeding eastwards, dykes more or less in alignment with those of Port Seton and Prestonpans have been recognised at intervals piercing the much older volcanic rocks of the Garleton Hills. As these examples afford no points of special interest, we may proceed to con- sider the mode of occurrence of those exposed along the same line of strike in the neighbourhood of Dunbar. E. b. b. The skerries lying off the coast between Dunbar and Belhaven Bay (Fig. 4, Chap. IX.), are portions of a large east and west dolerite dyke, and a number of smaller dolerite dykes having a W.8.W. to E.N.E. trend are exposed on the foreshore near Belhaven Point. Two of the minor necks, described already in Chapter IX., interrupt the continuity of two of these dykes ; but in spite of this the necks are not younger than the dykes, since a close inspection of the junctions shows that in each case the dyke is chilled against the neck and also sends small tongues of dolerite into it. In all other instances, the dykes clearly cut the vents, and in their neighbourhood have often undergone alteration to " white trap." Just east of Belhaven Point one of the dykes is crossed by a fault-breccia cemented with barytes. H. B. M. To the east of Dunbar along the coast at Millstone Neuk, a dolerite dyke, about 33 yds. wide, displays chilled margins and strikes nearly north-east. The north-west margin is vertical. Two sets of joints, one parallel and the other at right angles to the margin, are clearly recognisable. The dyke has a more north-easterly trend than the examples described above, but this may be due to the fact that it is in the position of an important fault, part of the movement along which may be contemporaneous with * or earlier than the intrusion. Various thin strings, containing calcite, quartz, galena, and barytes, run within it, parallel to the strike, and some distance off on the north- west side various other parallel lines of fault are observed, as well as two thin north-east dykes, from one foot to four feet thick, which are in the form of white trap. In the same neighbourhood, and about a quarter of a mile north of Catcraig, a decomposed dolerite dyke, running east and west and about three feet thick, is exposed on the limestone foreshore ; it cannot be traced more than 20 yds. Half a mile east of Catcraig, another dyke of the same thickness and direction, and also very decomposed, crosses the shore section. It can be traced to low-water mark, and * " The Geology of East Lothian," Mem. Oeol. Survey, 1866, p. 57. 164 Intrusions Later than Coal- Measures. is always either in the line of or close to a fault, which has a down- throw to the north. In the old quarry 500 yds. east of Catcraig we see again a basic dyke, about a foot thick, which is, no doubt, a con- tinuation of the dyke on the shore. c. t. c. The east and west dyke of Cockburn, in the south-east corner of the map, has also been proved to be a quartz dolerite. e. b. b. This category may be concluded by reference to a few igneous rocks of doubtful age. The fault fissure separating the Carboniferous and Old Eed rocks east of Biel is apparently occupied by a decom- posed basaltic dyke, very possibly showing the same relation as the Millstone Neuk dyke described above. In the north bank of Spott Burn, rather more than a third of a mile slightly east of south of Easter Broomhouse, we see a thin band of highly vesicular reddish brown igneous rock, about three feet thick, within a sedimentary breccia supposed to be of Upper Old Red Sand- stone age. The base inclines south-west about 10°- — much the same as the bedding of the breccia beneath — and this, taken in conjunction with the vesicles, suggests a contemporaneous character, but we know no other evidence of contemporaneous volcanic activity in the Upper Old Red Sandstone of the neighbourhood. The specimen sliced (10710) consists now of plagioclase and limonite, and we cannot say what the original character was. c. t. c, h. b. m. CHAPTER XV. FAULTS. In this chapter it is not intended to do more than describe a few of the larger or specially important faults. In the chapters describing the East Lothian coalfield, various other faults have already been mentioned on account of their interest from a mining point of view. THE LAMMERMUIR FAULT. The great Lammermuir E.N.E. fault is of a comparatively simple character, though of prime importance in determining the general structure of the district. The approximate position of the fault can nearly always be fixed without difficulty, while in several cases the exact course can be located, as in the stream sections south of Garvald. In the Papana Water, and at the head of the Donolly Reservoir, it can be seen to run in two closely neighbouring branches, which include a strip of Old Red Conglomerate between them. e. b. b. The last certain evidences of the continuation of the fault in a north-easterly direction are found in the Spott Burn, near Doon, and for half a mile lower down this stream. The Old Red Sandstone rocks, exposed near the portion of the burn referred to, consist of conglomerates of various degrees of coarseness, some with pebbles as much as six inches in length, and of thin beds of red sandstone mixed with the finer conglomerates. The coarsest types of con- glomerate are only found on the south-eastern side of the line of fault. The exact position of the fault is indicated in one locality, 100 yds. north of Doon, by the steep N.N.W. inclination, at angles varying from 55° to 70°, of certain coarse conglomerates, while the general dip in the neighbourhood is easterly, often about 10° or 15°. This fault strikes nearly at right angles to the Broxmouth and Innerwick line of disturbances, to be described subsequently, which it may be expected to meet in the drift covered tract a little north of Chesterhall. Although it has not been found possible to trace the continuation of the Lammermuir fault through this obscure ground, it is probable that it crosses the Innerwick-Broxmouth dislocation, though with diminished throw. It may, for instance, be represented on the coast between the Vaults and the White Sands by several faults, striking E.N.E., which are accompanied with a considerable disturbance of the dip. These are nearly in the line of the fault in Spott Burn, and most of them seem to throw down to the north-west also. The fault which accompanies the broad dolerite dyke has probably a throw of about 100 ft., for the limestone on the •south-east side appears to be the Skateraw Middle Limestone, while 166 Faults. that on the north-west is probably the limestone of Chapel Point. The dyke is veined with little strings containing calcite, barytes, and galena, but it does not seem probable that it has been affected by the whole of the fault movement, for the crushing inside is not great, and both of the chilled margins are intact. Nearly a quarter of a mile north-west of this broad dyke, two much thinner parallel dykes are seen, very near the north side of a fault with a downthrow to the north. c. t. c. THE DUNBAE-GIFFOED FAULT. The Dunbar-Gifford Fault is a flanking fault running parallel to the major Lammermuir dislocation. The fault can readily be followed almost as far inland as the GifEord Water. Beyond this point its continuation is rather hypothetical ; the reasons for its insertion in the map have already been discussed in the stratigraphical descrip- tion (Chap. VI.). e. b. p THE OLDHAMSTOCKS, INNEEWICK AND BEOXMOUTH N.N.W. FAULTS. The narrow tract of Carboniferous rocks which lies south-east of Dunbar is bordered on the west by a great line of disturbance, gener- ally striking N.N.W. , which passes by Oldhamstocks, Innerwick, and Broxmouth. The strata near this line have been compelled to strike nearly parallel to it, and are inclined at high angles. In Ogle Burn and Braidwood Burn we find, mixed with the coarse Lammermuir conglomerate (of Old Red Sandstone age), on the west side of the hue, thin strips of Silurian greywacke and shale, considerably crushed, and in places striking N.N.W. almost at right angles to the usual Silurian strike in the Lammermuir s. In the former burn some beds of the Cementstone group are seen dipping W.S.W. at 80°, close on the east side of the main fault, and a few yards further east there is, perhaps, another fault — possibly a continuation of the big east and west fault of Cove. Near Broxmouth the disturbance is represented by several lines of fracture and contortion (Plate VI.). The beds are frequently reversed, and in the railway cutting the sandstones and shales below the Skateraw Middle Limestone are thrown into small folds, some with both limbs inclining west, and crossed by several small thrusts inclining west at low angles. On the shore N.N.W. of Broxmouth, the beds belonging to the Carboniferous Limestone series, the Cementstone group, and the Upper Old Red Sandstone, are generally reversed and dip steeply west. Near the fault, which separates the beds of the Cementstone group from those of the Carboniferous Limestone series, there is a thin bed of dolomitised limestone, the stratigraphical relations of which are not clear. These phenomena near Broxmouth indicate that in this locality the beds west of some of the lines of fracture have been to some extent thrust over the younger beds on the east. It may also be said that on the coast east of Skateraw, and nearly a mile and a half E.N.E. of the line of disturbance referred to, the Skateraw Middle Faults. 167 Limestone is often folded into small anticlines and synclines, with axial planes striking about N.N.W., and generally either vertical or inclining west. In one place, also, a little thrust is seen, dipping west at about 20°. FAULTS IN THE CATCRAIG QUARRIES. The limestone which has been quarried in the northern quarry, just south of high water-mark, at Catcraig, is the Skateraw Middle Limestone — the bed which contains the Saccammina band — but the limestone of which the base is seen at high water-mark is the Long Craig Upper Limestone, and a fault must pass between these two with a downthrow to the south of 40 or 50 ft. The main break is not distinct in the quarry, but parallel slicken-sides are conspicuous, and the limestone has been converted in parts into a soft brown mass, which consists chiefly of the brown oxide of iron,* together with scattered crystals of ferriferous carbonate (perhaps dolomite in part), galena and thin strings of barytes. The barytes is often in the form of small water-clear crystals, which are stated by Mr. H. H. Thomas to show the forms c (001), m (110), and d (102). A little east of this quarry the fault seems to divide, some branches running N.N.E. and disturbing the outcrops of the Skateraw Lower and Middle Limestones on the foreshore, while another branch pro- ceeds south-east through the north-eastern end of another old quarry, and throws the Saccammina band on its south side against a lower portion of the limestone. c. T. c. FAULTS ON THE COAST NEAR NORTH BERWICK. A large fault with an east and west strike crosses Canty Bay, and throws the beds below the green ash down to the north. Its course inland is difficult to trace, but it is probably the same fault as that seen at the west foot of the North Berwick Pier, where the down- throw is also clearly to the north. Another large fault, striking north and south, passes a little west of Weak Law, and throws down to the east. It continues seaward, and truncates the east end of Byebroughy Scar. G. b. * " Disappearance of limestones in High Teesdale," Geol. Mag., 1903, p. 259. CHAPTER XVI. PLEISTOCENE* AND RECENT. Stage of Maximum Glaciation. The whole of East Lothian bears evidence of having been overridden by land ice. The direction of striae and of the general moulding of the surface of the country indicates that the current of ice which crept forward across the district came from the west, following roughly the trend of the Central Valley (see Fig. 10). This inference is con- ef° V t*V d +LAUDER + GREENLAW Fig. 10. — Map showing the direction of the Ice-Movement in East Lothian at the period of Maximum Glaciation. firmed by the " carry " of such of the boulders, occurring in the drift, as have a recognisable local source. But when considered more closely, the striae, moulding, and drift-transport all indicate that the course followed by the ice-stream was in the main distinctly less north-easterly than the line of the great Lammermuir fault, which here defines the southern limit of the Central Valley. Thus, erratics of Carboniferous rocks are carried out in abundance on to the Silurian * The area south of the Garleton Hills has recently been described by P. F. Kendall andE. B. Bailey, Trams. Roy. Soc. Edin., 1908, vol. xlvi. p. 1. This paper, which includes among other things, an account of previous work, has been largely drawn upon in the sequel without detailed acknowledgment 168 Stage of Maximum Glaciation. 169 Uplands. Again, where the Central Valley terminates, merging in the wider expanse of the North Sea plain, the ice-stream swung round, as is clearly shown by striae, into approximate parallelism with the coast. This deflection was probably due to congestion in the en- closed basin of the North Sea, at that time flooded by the ice-sheet radiating outwards from the Scandinavian peninsula. The glacially transported boulders enable us further to locate the source from which the ice-stream, crossing East Lothian, was largely supplied. Highland Erratics. — The occurrence of erratics of Highland schists along the northern front of the Lammermuirs has been recorded by Prof. James Geikie.* Most of them consist of coarse pebbly schistose grits of the type prevalent in the Southern Highlands. Occasional blocks of mica schist have been noticed, and also small pebbles of quartzite, originally derived from the Central Highlands. Near Tynehead, the boulders of schist are so numerous as to figure largely in the " dry stane dykes." In other parts, pebbles of Highland schists may generally be found without difficulty amons the stones ploughed up in the fields. It is evident, then, that we are justified in assuming a Highland source for much of the ice which traversed East Lothian. Its intermediate route can only be reconstructed from evidence obtained in districts lying outside the district under consideration ; but the task of reconstruction has long since been accomplished, and the reader is recommended to consult some map f showing the general glaciation of Scotland for a graphic representation of the essential facts. Here he will see that towards the west end of the Central Valley, the main ice cap of the Southern Uplands proved sufficiently powerful to ward off invasion from the Highlands, and the two great ice-streams, meeting at the base of the southern hills in the plain of Ayrshire, turned north-east and south-west to escape either way along the Central Valley. Before the Lammermuirs were reached, however, the Highland stream, which had been diverted towards the north-east, was able to push its southern companion back upon itself, and to creep up obliquely on to the Silurian Uplands. Its subsequent course across East Lothian has already been indicated. Southern Upland Erratics. — But while Highland erratics may be found over the whole extent of East Lothian, it is now known that pebbles of Silurian greywacke are also of frequent occurrence in the boulder clay, even as far north as Pencaitland. The recogni- tion of this important fact is due to evidence brought forward recently by Mr. Whalley before the Edinburgh Geological .Society ; as the greywacke pebbles are equally abundant in the boulder clay on both sides of the Tyne valley near Ormiston, it is obvious that they have not merely been picked up by the ice-sheet from the gravels of this river ; in fact, the most probable explanation of their mode of occurrence is to suppose that they were derived from tributary glaciers nurtured in the more westerly valleys of the Southern Up- lands, at a time when the main ice-stream did not overtop the Lammermuir Hills to the south, but was restricted to the valley of the Forth. * Great Ice Age, 1894, p. 195. t E.g., Sir A. Geikie, Scenery of Scotland, 1901, Plate IV. 170 Pleistocene and Recent. Strice and Ice-moulding. — We may now briefly notice a few par- ticular instances of glacial erosion. In the first place, striae are only well preserved on the hard volcanic rocks of the district. Examples are numerous in the Garleton Hills and adjoining district, but even here it is obvious that only a minute proportion of those originally impressed upon the rock surfaces have been retained — in positions, that is, which are open to observation, and therefore subject to atmo- spheric erosion. Where the protective covering of drift has only recently been removed, as in the making of the small reservoir on the hill close to Gullane, the glaciated surfaces are frequently found in a beautiful state of preservation ; apart from the northern district where the strise observed are directed towards the E.N.E., ice scratches have been noticed only along the coastal area between Dunbar and St. Abb's Head (one-inch map 34). They are so few that they may be tabulated as below : — Shore south-east of the Old Harbour, Dunbar, E. 5 S. (Mr. Maufe). Catcraig Quarry two miles E. of Dunbar, E. 15 S. (Professor Young). Shore close to Catcraig, E. and E. 10 N. (Mr. Clough). A striated pavement, Thornton Loch, 5 miles S.E. of Dunbar, E. 10 S. (Professor Young). St. Abb's Head (one-inch map 34), E. 25 S. (Professor Young). The following is Professor Young's account of the striated pave- ment : * "At Thornton Loch, Boulder Clay is exposed between tide- marks, and blocks washed out of it strew the shore for some distance. At one point, over a space of about 40 square yards, the blocks em- bedded in the clay have their surfaces on the same plane ; and over- riding the irregular striations, which are deeply impressed, another series of parallel grooves runs in a direction uniform for every stone over the space, viz., E. 10 S. The blocks seem to have first under- gone the tumultuous scoring before reaching their present position, and afterwards to have been subjected to the friction which has converted them and the intervening Boulder Clay into a striated pavement, now slowly wasting under sea action." As regards the glacial grooving of East Lothian, it is noteworthy that this was one of the first localities for which an accurate account of the phenomenon was published.")" Deep glacial grooves have been cut in many of the trachyte hills north of Haddington ; they have been taken advantage of by the later marginal streams, to be described pre- sently, and have thus been somewhat modified in form. Larger though less pronounced hollows, attributable also to direct glacial erosion, are characteristic of the country lying south and east of Haddington. It is common to find the western face of any upstanding mass of rock, such as North Berwick Law, showing more intense glaciation than the eastern, and it is correspondingly easy to collect fresh specimens on such western exposures. Traprain Law furnishes an excellent example of the familiar crag and tail structure, with an orientation clearly indicating the E.N.E. course followed by the ice-sheet. g. b., e. b. b. * " Geology of East Lothian," Mem. Oeol. Survey, 1866, p. 64. The pavement is no longer observable. t Sir A. Geikie and Professor Young, " Geology of East Lothian," Mem. Oeol. Survey, 1866, pp. 1, 63, 64. Stage of Maximum Glaciation. 171 Boulders and Boulder Clay. — The coast lines offer specially favour- able opportunities for observing the larger ice-carried boulders. Scattered over the foreshore east of Dunbar, for instance, we find many boulders which are foreign to the district, some of which, for example, those of epidiorite and schistose greywacke, may have been carried from the Western Highlands. Between Dunbar and the foot of Broxburn there are many blocks of a coarse, reddish yellow sandstone, crowded with small pieces of compact unfossiliferous limestone or cementstone. These blocks closely resemble parts of the Craigmillar Sandstone of the Edinburgh district, and if they have been derived from this source, they indicate a " carry " in much the direction of the striations observed. It is noteworthy that boulders of this type are abundant on the foreshore to the east of Port Seton, which lies on the direct route for the ice sheet between Craigmillar and Dunbar. c. T. c, e. b. b. The boulder clay has up to the present only been described in respect to its far-travelled contents. Apart from these its ingredients vary locally from place to place, as might be expected. Thus in the coal-field it is often a stiff stony clay almost black in colour, while in the area occupied by the Cementstone group, south of the Tyne Valley, the matrix is a tough, bluish-grey to purplish clay. Very different both in colour and texture is the red, sandy boulder clay of the Old Red Sandstone areas, while the equivalent deposit which covers the large tracts of conglomerate of the same age can, where sections are not available, scarcely be distinguished from a gravel. The boulder clay of the Silurian Uplands is, as a rule, very stony and of a fawn colour. Roughly, these different types of drift are confined to the outcrops of the various corresponding rocks. Sometimes the transition is very abrupt ; thus, immediately after crossing the Dunbar-Gifford fault, in the eastern part of its course where the drift cover is not thick, the boulder clay takes on a red colour, and the soil becomes generally lighter. In other cases there is a very marked overlap of the drift in an easterly direction, and near Fala the boulder clay, which is particularly thick, is often of the black stiff type characteristic of the coal-field, and crowded with limestone and Pentland lava frag- ments. H . B . M . Another instance of deep boulder clays occurring in the Garleton Hills may be noticed on account of the special interest which attaches to it. The superficial deposits are evidently thick in the hollow through which flows the eastern PefEer Burn, the burn entering the sea at Pefier Sands ; while at Beanston, north-east of Haddington, a deep well failed to penetrate the drift. It is suggested that this may indicate the existence under the boulder clay of an old channel of the Tyne reaching the sea at PefEer Sands. The constriction of the present Tyne valley above East Linton supports the view that this portion may be of comparatively recent date, but on the other hand the importance of the present estuary must be taken into con- sideration. G. B. Gigantic Erratics. — We may refer now very briefly to certain large masses of limestone which are regarded as gigantic erratics transported by the ice. 172 Pleistocene and Recent. The most conspicuous example is that of Kidlaw, a mass a third of a mile long and a quarter broad. The other two are of smaller size, one at Marl Law quarry, a mile N.W. of Fala, and the other at Woodcote Park, a mile to the east of Fala. It will suffice here to give the reasons for considering the Kidlaw mass a " boulder " rather than a normal outlier. 1. The few exposures in the neighbourhood, and general con- siderations as to the geological structure of the district, point to the conclusion that the limestone is resting on sediments of Upper Old Red or early Calciferous Sandstone age, with associated igneous rocks. The limestone appears, moreover, to belong to the middle and not the basement portion of the Lower Limestone group. 2. The whole mass is in a completely shattered state. 3. There is a great abundance of limestone blocks, both large and small, in the boulder clay of adjoining areas, whether it rests upon Silurian, Old Red, or Carboniferous strata. Similar and quite indubitable cases of transport of huge rock masses are, of course, well known in England and elsewhere. B. b. b. Coal near Oldhamstocks. — The following example serves as a con- necting link between these great transported masses and the scattered stones so familiar in ordinary boulder clay. It was reported locally that coal outcropped in a burn rather more than a mile and a half south of Oldhamstocks Church, but on examination it was found that the coal was merely in the form of pieces included in the boulder clay, which in this locality was of a chocolate or bluish colour. The pieces are very abundant, often four or five inches long, and are associated with many fragments of a richly fossiliferous limestone, resembling beds in the Carboniferous Limestone series. The nearest locality at which such limestones are known is three or four miles away to the north, but it seems likely, especially in view of the numerous bits of coal, that they have been carried from a much farther distance, namely, from near the east side of the East Lothian coal basin, which is almost 20 miles away to the west. c. t. c. The Retreat of the Ice-Sheet. With the period of ice-melting and the emergence of rock surfaces a new form of erosion began. It has been observed in the analogous Arctic and Antarctic examples of modern times, that where an ice- sheet abuts against a hill-slope it generally rises abruptly from the latter in the form of an ice cliff. Thus it happens that a distinct channel is provided along the ice margin, and, where the glacier is but little fissured, this channel serves as a stream-course, which is supplied by the drainage from the hill country and from the ice-sheet itself. In East Lothian such stream courses, called into being during the retreat of the ice-sheet, have often been sufficiently deeply eroded to remain as recognisable features in the present day landscape. Of ' cognate origin are other channels cut by streams which did not neces- sarily follow the ice margin at all, but which issued from lakes held up by that margin — lakes which have vanished on the withdrawal GLACIAL DRAINAGE CHANNELS AND GRAVEL ■*■ Best sections showing intercalation of Sana's and Boulder Clays 'iW'- Sand and Gravel. ffeayy solid lines = Dry Glacial Drainage Channels. Broken heavy lines = Stream - containing Glacial PLATE YII ON THE FLANKS OF THE LAMMERMUIR HILLS ra.ino.ge Chorine, Retreat of the Ice-Sheet. 173 of the ice-sheet, like those described by Agassiz * in classic Glen Roy. The gravel deposits which accumulated at the mouths of these glacial drainage channels, and in the various lakes, also form a great feature in East Lothian geology. These phenomena of the retreat of the ice-sheet are most con- spicuous along the northern and eastern flanks of the Lammermuir Hills, and again in the detached area of the Garletons. G. B., E. B. B. LAMMERMUIR AREA. Glacial Drainage Channels. — With regard to the Lammermuir area, a mere outline of the more important features is all that need be given here, as it has so recently formed the subject of the conjoint paper with Professor Kendall already referred to. It may be added that our indebtedness to Professor Kendall is fundamental, since marginal drainage phenomena had never been fully interpreted in this country before the appearance of his original paper on the glacier lakes in the Cleveland Hills, f Glacial drainage channels of both the classes referred to above are well represented. The artificial loch of Pres- mennan lies along a strictly marginal channel. It has been incised into the smooth slope of a steep hillside, following instead of crossing the contour lines. It is evident, therefore, that the actual ice front must have provided the outer wall during the initiation of the stream channel. In other cases the long sinuous courses of the valleys show that they were not excavated immediately along the ice margin, but merely received their waters from glacially dammed lakes. A good example of such a winding valley is the streaniless ravine which runs to the south of Whitelaw Hill. The most striking characteristic of the glacial drainage channels, considered as a group, is the fact that many of them are entirely dry, now that the ice-sheet no longer diverts the drainage of the country along them. Among numerous fine examples we need only notice here the various dry valleys between Gifford and Garvald, the grand gorge, 200 ft. deep and cut in the solid rock, which separates Deuchrie Dod from the main chain of the Lammermuirs, and the less imposing, but very beautiful, channel (Plate VIII.) which joins the Spott Burn a little above the village, and within easy walking distance of Dunbar. In many other cases, however, the glacial drainage channels have still retained a more or less considerable stream since the withdrawal of the ice. Such valleys can be readily recognised on the map owing to their evident connection with the dry valley system. In several cases, too, it can be shown that the comparatively small stream now left in possession has not effected any deepening of the valley during post-glacial times. Under such circumstances, tributary dry valleys coincide in level with the bottom of the stream-con- taining valley at their point of junction. A good example of this is afforded at the junction of the valley, already mentioned * " The Glacial Theory and its Recent Progress," Edin. New Phil. Journ., 1842; vol. xxxiii. p. 236. t Q-J-0.3; 1902, vol. lviii. p. 47. 174 Pleistocene and Recent. (Plate VIII.), with the Spott Burn, some little distance above the village. In other cases post-glacial deepening has been effected, but not to such an extent as to remove all traces of the floor of the old glacial channel ; for, as is well shown by the Braidwood Burn, south of Innerwick, the recent stream, with its greatly diminished volume, has merely succeeded in cutting a miniature, gorge that winds to and fro along the old bottom, the latter being in large measure still pre- served intact. Some peculiarities in the relations of the various glacial drainage channels suggest the existence of oscillations which affected the position of the ice front during its gradual retreat. The Rammer Cleugh channel behind Deuchrie Dod is a case in point. This splendid dry valley bifurcates towards the east, a high level channel leading away from the main ravine, and following a slightly more northern course. It is obvious at once that the two channels cannot have originated successively during a continuous withdrawal of the ice front towards the north, for the shallow northern trench could not have been supplied with water at any period since the establishment of the deep southern gorge. It seems probable then that the two were formed during a period of oscillatory readvance of the ice- sheet, following upon a rather rapid retreat which had temporarily uncovered the site of the northern channel. We may suppose that the latter, after some slight excavation by the escaping waters, was blocked by the readvancing ice-sheet, under which circum- stances a more southern channel would perforce be called into existence. If it stood by itself, this example might be interpreted as acci- dental ; it might be assumed that the glacial drainage channel hap- pened to be split by some original unevenness of the surface, and that of the two courses, which thus originated, the northern one gained ascendancy, until at last it trapped the whole of the water supply. But Black Law furnishes an even clearer case of the same kind ; in fact, the channel behind Deuchrie Dod has been selected as an illus- tration, chiefly because it provides further, quite independent evi- dence of oscillation of the ice front. The readvance in this case is indicated by a group of morainic mounds charged with great blocks of red sandstone, which have been carried from the Lowlands into this valley of the Silurian Uplands. They rest on the very bottom of the gorge, near its western extremity, and have evidently been deposited in it as a result of a forward movement of the ice, sub- sequent to the complete excavation of the channel by the marginal drainage. : j p The Lammermuir Terrace and the Coastal Spread. — Reference has previously been made to the glacial sands and gravels which accumu- lated during the retreat of the great ice-sheet. They are concen- trated for the most part into two definite and quite distinct areas (Plate VII.). The first of these is a well-marked belt or zone of maxi- mum accumulation, extending from Tynehead, in the west, right round the hills to Oldhamstocks, in the east, while the second includes what may be termed the coastal spread. The former belt is roughly contained within limits set by the H (3 cq Retreat of the Ice-Sheet. 175 700- and 500-ft. contours respectively. It appears to be of the nature of a great terrace filling in the slack between the ice margin and the hills, and largely supplied by detritus washed down from the latter.* In places the deposits are of a coarse gravelly nature, but deep sections of fine sand with seams of laminated clay appear to indicate that in some measure this composite terrace collected in the tranquil waters of marginal lakes. The height to which these fine deposits rise in the Upper Keith district suggests that they must have formed in a mar- ginal lake of which Deuchrie Dod furnished the eastern barrier, and which, therefore, was fully 14 miles in length. With the deepen- ing of the Rammer Cleugh channel, behind Deuchrie Dod, the lake was drained, and its deposits were exposed to vigorous erosion. With the further retreat of the ice, fresh opportunities for denudation were offered, which still more reduced the continuity of the deposit. It is interesting under these circumstances to find, in the Upper Keith sections, evidence which strongly supports the inference regarding the oscillatory^ 'nature of the retreat of the ice-sheet, already considered in connection with the Rammer Cleugh channel behind Deuchrie Dod. An important bed of boulder clay intercalated in the sands has been traced with tolerable certainty for a distance of a mile, parallel to the old ice margin, and a quarter of a mile, at right angles to the same, without any indication of the original limits of the deposit. We take it that this indicates a minor readvance of the ice margin over the floor of the lake, which spread out in front of it. We may add that without doubt the boulder clay in this case was deposited by the main ice-sheet, and not by a local glacier from the hills, because it is charged with big blocks derived from the Lowlands, set, as may be seen in the unweathered exposure of the Red Scar f (a little north of Costerton Cottage), in a black, stiff matrix, showing transport from the coal-field. Two of the sections illustrating the position of this intercalated boulder clay are specially clear. They both occur along the course of the Keith Water. The first constitutes the Red Scar, and the second lies just to the west of the road from Upper Keith to Ormiston. The details are as follows : — Red Scar. W. of Ormiston Road. Ft. Ft. Sand . . . . . . . . . . 53 Not exposed. Boulder clay . . . . . . 13 6 Sand 15 65 Boulder clay, base not seen . . 37 33 E. B. B. Somewhat similar evidence, again suggesting oscillations of the ice front, but at a later stage, is furnished by the mining operations in the neighbourhood of Ormiston and Pencaitland. An old glacial drainage channel passing close by the latter village has been proved to contain a considerable depth of clay and sand, and in several places * Originally (Trans. Roy. Soc. Edin., 1908, vol. xlvi. pp. 13, 14, and 17) it was supposed that all the Silurian pebbles in the gravels north of the boundary fault were washed down from the hills to the south. As previously noticed, however, following up work by Mr. Whalley, we now know that Silurian pebbles occur through- out the boulder clay of the low country, but there can still be no doubt that the local hills supplied much of the material of the gravel spreads. f Not named on one-inch map. 176 Pleistocene and Recent. it has been found that boulder clay occurs lying over sand and mud. The journal of one of the bores reads as follows : — Surface, 1 ft. Clay and stones, 17 ft. Sand and gravel, 13 ft. 10 in. Mr. Whalley has recently given the Edinburgh Geological Society an account, not yet published, of another very interesting buried channel at Pencaitland, which, in some features, agrees with the description given above. c. b. c. The coastal spread of sand and gravel cannot be regarded as a unit even in the extended sense in which that term might be used to describe the complex Lammermuir terrace. It owes its continuity to the juxtaposition and overlap of deposits formed successively and not contemporaneously. It is probably the accumulation which formed where the mouths of the glacial drainage channels debouched upon the coastal plain, and, as these came into being in succession from south-east to north-west, following the retreat of the ice-sheet, it is concluded that the coastal sands and gravels in the eastern area were formed before those of the western : that, for example, those near Oldhamstocks belong to a date prior to those about the mouth of the Tyne. The finer deposits, which figure largely in the Dunbar neigh- bourhood, may have, to some extent, collected in waters held up in front of the ice margin. A section in a sandpit in the bank behind the 20-ft. raised beach just east of Dunbar shows boulder clay overlying glacial sands, and thus indicates once again the oscillatory nature of the retreat of the ice-sheet. The materials of the coastal spread were no doubt largely derived from the cutting of glacial drainage channels and from the denudation of the great Lammermuir terrace. Silurian pebbles are very abundant in the gravels around Innerwick and Oldhamstocks, and even at Dunbar they figure very prominently. In fact they form as much as 49 per cent, of the pebbles collected from several gravelly surfaces in the fields near the town. At Oldhamstocks, where the coastal spread and the Lammermuir terrace come into contact, an extremely interesting and complex history can be deciphered. The deep cut valley running through the village is bordered by a series of three or four old river terraces, shown as alluvium on the map. The highest of these lies about half-way up the sides of the valley, and is not much lower than the bottom member of a higher series of gravel terraces, also coloured as alluvium, but with the addition, in places, of the flu vio -glacial sign. The distinction between the two series is arbitrary, but has been made, since it is not possible to distinguish the lower terraces from normal river alluvium, while the higher terraces are certainly glacial. They slope in the same direction as the present stream, but more gently ; the highest one, for instance, is about 100 ft. above the stream at Oldhamstocks Church ; near the bridge, however, a mile lower down, it is nearly 150 ft. above the stream. They must be referred to a period when the valley was much less deep and constricted than at present, and as none of them can be traced more than a little way east or north-east of Berwick Burn, in spite of the general fall of the ground in these directions, it Retreat of the Ice-Sheet. 177 seems probable that the old stream which formed them was blocked by the margin of the ice-sheet then occupying the lower ground. c. t. c, H. B. M. Local Glaciers. — We have in preceding paragraphs been dealing with phenomena which marked the retreat of the great ice-sheet from about the 1000 ft. level downwards. Above this, there are very few signs of marginal drainage effects (Plate VII.), and the theory has been developed that at first, when the great ice-sheet drew back, a local ice cap was left on the hills which protected them from the ravages of stream erosion. Very simple and straightforward evidence of local glaciation is in fact afforded both in the neighbourhood of Lammer Law and also of Soutra Hill. In the former case a neatly cut high level channel leads right across the ridge bounding the Valley of the Sting Bank Burn on its northern side. It shows all the characteristics of a winding stream course, with steep banks facing every curve. Its elevation above the Sting Bank Burn is about 200 ft. ; it is now quite dry. To explain this high level channel we must admit that the course of the Sting Bank Burn was choked with ice streaming in from the tributary valleys to the south, and that a small lake was thus enclosed, in the north-eastern angle of the valley, which drained northward across the ridge so that a stream course was excavated in what is at present an impossible situation. As the water which cut this channel drained outwards from the hill country, we have clear indication that local glaciers remained in the high valleys after the great ice-sheet had shrunk to a lower level. Another high level channel of the same kind, also leading out from the hill country, may be seen just west of Soutra Hill. It is in fact probable that the Linn Dean Water lying east of Soutra Hill originated under precisely similar conditions to those outlined above ; but being sufficiently deeply cut, it has permanently intercepted the upper portion of the Armet Water, and so has not been left dry on the dis- appearance of the local glacier. Another interesting but complicated case in the Cowie Burn Valley, near Lammer Law, is discussed in full in the paper already referred to. There seems evidence here of actual marginal drainage along the front of a local glacier occupying the upland valley. e. b. b. An Up/jey Limit to Possible Submergence. — When we begin to con- sider the lower limit to which these marginal phenomena descend, the question of the level at which the sea stood during the retreat of the ice-sheet is immediately raised. The clearest evidence is afforded by a well-defined dry valley, as pointed out by Professor Kendall, cut in rock and terminating near Eweford, slightly more than a mile south- west of Dunbar. This channel only ceases to be a well-marked feature on crossing the 75-ft. contour, so that high-water mark at Dunbar, when the ice drew back, cannot have reached the level of the lOO-ft. contour of the present time ; probably it did not surpass even the 75-ft. contour, if indeed it reached it. In like manner a dry valley leaving the Spott Burn near the rail- way is recognisably cut down to the 75-ft. contour, but not to the 50-ft. C. T. C, H. B. M. 12 178 Pleistocene and Recent. « Corroms. — This brief abstract may be terminated with an account of the modification, by corrom formation, of the glacial drainage system of the Lammernmirs. Corrom is a Gaelic word (cothrom) used in place names in Argyll- shire to denote a delta-watershed. Its literal meaning is a " balance," and its use implies that a stream issuing upon a delta of this character has the chance of flowing either into one drainage basin or another. Corroms are of frequent occurrence, blocking the old glacial drainage channels. A priori it is obvious that these valleys, cut to very low gradient by the powerful torrents which originally fashioned them, and as often as not quite open at their heads, must be particularly prone to such modification. The corrom is of course built up by some tributary or other, entering the main valley down a steep gradient, and no longer capable of carrying away its load of gravel and sand along the very gentle incline of the glacial channel. A concrete example will serve to show what important readjust- ments may result from corrom formation. At present, Cocklaw Hill is separated from the Lammermuir chain by a deep narrow valley, which undoubtedly served as a glacial drainage channel leading south- east. In fact, it owes its continuity to the glacially diverted torrent which for a time occupied it, since it is clear that in preglacial times its course was interrupted by a watershed. On the withdrawal of the ice-sheet, the Aikengall Burn, which in preglacial times flowed into the Oldhamstocks Burn, built out its cone into the deserted through- channel, and thus gave rise to a corrom or delta-watershed. As one might suppose, the corrom here is not the only cone built out into the glacial drainage channel ; in fact, every stage in the growth of dry deltas is illustrated in this beautiful valley (Plate IX.). An equally striking example of corrom formation is provided by the Dry Burn valley, somewhat farther north. In this case it is the How Burn which is responsible for blocking the main channel by the delta which it has built out across it. Here, and also in the former instance, it seems probable, to judge from the erosion effects, that the reversed drainage, initiated upon the corrom, had formerly a much greater volume than at present. In fact, it is likely that these corroms were formed while glacial conditions still persisted, and when the floods of summer frequently attained very large dimensions. Corroms of minor importance are very numerous throughout the area included in the map. Another modification of cognate origin is the entire obliteration of a glacial drainage channel by a delta. A case of this sort is well displayed at Common House, two miles S.S.W. from Spott. E. b. b. THE GARLETON AREA. High Level Channels. — The peculiar features produced by marginal streams are well preserved on many places along the north face of the Garleton Hills and the rising ground towards East Linton. These hills are largely composed of bare rock and descend toward the northern plain by a series of step-like features. The steps are not quite horizontal along their greater length, and appear to represent the furrows worn by successive marginal streams. Of course, to complete the channels of these streams, one must in imagination replace the glacier lobe B < H O Retreat of the Ice-Sheet. 179 which protruded down the Tyne valley and which supplied the northern containing wall in every case. A further stage in the development of marginal channels is reached in cases where the step feature is faced along its outer edge by small ridges of bare rock. The name of marginal footings may be applied to these ridges ; they are well shown along the northern face of the Garleton Hills, and represent portions of the north side of the channels, the pedestal, as it were, upon which the ice wall stood when the marginal stream had sunk its bed some little way into the rock of the hillside (Fig. 11). MARGINAL CHANNEL Fio. 11. When the ice finally melted, the small mass of protected rock was left projecting sharply above the old stream bed, and its character as a remnant of a stream bank is still often tolerably obvious. A perfect example of a step feature, along which a marginal stream has once flowed, occurs on the face of the Garleton Hills, east of the road passing between the two patches of ashy marl shown on the map. Looking east from the road we see a bold scarp face of the fine trachyte, and at the foot of this is the step feature referred to. Close to the outer edge of the step, at a distance of 400 yds. from the road, is a perfect example of the rocky remnant (marginal footing) of the outer wall of the old channel. The footing, which can be easily recog- nised by aid of the little diagram given in the text, forms a little narrow ridge more than 100 yds. long. There is no difficulty in tracing the old courses of these marginal streams along the face of the Garleton Hills eastwards, and near East Linton they are unusually well seen. A small group of marginal footings can be easily recognised upon the hillside north of Pencraig Wood, near Over Hailes. On the south-west side of the East Linton railway cutting, west of the town, we may study the different positions of the marginal stream as it fell from one level to another. A few hundred yards across the railway to the north-east we reach an area of flatfish ground in which the gravel swept along by the streams was accumulated. Low Level Channels. — As the ice sheet sank still further, it left remnants heavily loaded with the mud and stones that formed the boulder clay * when the containing ice melted ; while, here and there, more or less isolated masses of rock projected above its surface. The * Many geologists favour a more strictly subglacial origin for boulder clay than that advocated here. This difference of view does not, however, essentially affeot the line of argument developed in the succeeding paragraphs. 180 Pleistocene and Recent. nature of this low level ice has led to a sharp contrast between the manner of preservation of marginal stream channels occurring in the high and low ground respectively : in the former, with the exception of the small rock footings, one bank only, the rock bank, is left and all trace of the ice bank has gone, but in the later low level streams the position of the ice bank is still preserved by the large residue of enclosed mud and stones left when the ice melted. Old stream courses, formed at this epoch, are thus easily recognised. A junction of the mud-loaded ice and bare rock margin occurred along the north face of the Hill of Balgone, the escarpment of the basaltic lavas. Previously to meeting this junction, the water of the melting ice probably flowed exclusively over the latter ; but, on reaching the typical hollow at the rock and ice junction, down it plunged, deepening its bed locally as every waterfall does. It swept away not only the ice, but also the enclosed mud and stones, the material, that is, from which boulder clay might have been formed later on. When the ice bank melted, its contained material was largely left, but along the site of the old stream course there was none to leave, so that, in a certain sense, the position of the old bank is determined by the deficiency of boulder clay along the site of the stream bed. If this hollow be approached from the west, it is obvious that since the present configuration of the country was acquired, there never has been and never could be a stream capable of cutting this deep hollow with rock on one side, and boulder clay on the other — a fact that was clearly recognised by Dr. Young in the former memoir on the district. A similar hollow, with rock on one side and boulder clay on the other, occurs to the south-west of Smeaton House, near East Linton, and has been artificially banked into a small lake : the rock face here has been slightly undercut by the stream. Englacial Streams. — These phenomena suggest a novel interpreta- tion of the hollows in the boulder clay occurring on the two flanks of North Berwick Law. These depressions have usually been regarded as small "diversion basins "• deepened by the scour of the glacier as it swept round the obstacle. But may not this isolated pillar of rock, by arresting the flow of the ice, have given rise to two per- manent crevasses into which small streams poured during the period of melting ? As before, these would sweep away part, at least, of the material enclosed in the ice, and eventually would cause deficiency hollows in the ground moraine, as finally deposited. Both hollows are more or less silted up ; the more northerly and larger mainly by material brought in by a small stream ; the other by downwasn from the margins of the hollow itself. Englacial streams, by a similar washing away of the material that ultimately formed the boulder clay or ground moraine, probably gave rise to a great number of the hollows of variable size, since silted up, which are a regular feature of the drift-covered area of low ground in the North Berwick and similar districts. In addition to hollows, terraces were also cut in the ice by these streams, and, when the ice melted, their former position is often indicated by faint terraces in the boulder clay now remaining. There are a great number of these vague terraces below the 100-ft. contour Raised Beaches. 181 between Aberlady and Tyne Mouth, and many are in positions in which no running water could have flowed since the boulder clay was formed on the disappearance of the ice. These features point to the prolonged existence of the ice over this area where the 100-ft. beach is persistently missing. The view here taken is that, during the epoch of the 100-ft. beach, much of the area was protected under a stagnant remnant of the great ice-sheet, and that the sea cliff, cut in ice, although the latter was heavily drift laden, can naturally no longer be identified. g. p.. Raised Beaches. Bast Lothian cannot be regarded as a satisfactory district for the study of any of the raised beaches, except the one which occurs at about 25 ft. above Ordnance Datum. The observations made in various localities, in regard to the higher beaches, present certain difficulties of interpretation and even an apparent lack of harmony. The evidence is of a very fragmentary character, and no theory has as yet been advanced which will give a plausible account of the phenomena of the whole area. Under the circumstances it is unwise to attempt to arrange the available matter in strict chronological order so far as the higher beaches are concerned. For them the coastal areas will therefore be discussed in succession from west to east. Then will follow a separate description of the 25-ft. beach which is very clearly de- veloped. E. B. B. UPPER RAISED BEACHES. Prestonpans to Aberlady. — In the area east of Prestonpans, the ground beneath the 100-ft. contour is irregularly covered by sandy deposits, which might readily be ascribed to high level beaches. Just south of the wood which lies to the north-west of Longniddry, a distinct terrace at a level of about 40 ft. is traceable for some little distance, and it is possible that this may represent a beach margin. E. B. B., E. M. A. Aberlady to Tyne Month. — Excellent examples of raised beaches and deposits of blown sand occur in North Haddingtonshire east of Aberlady. In a large number of cases the two are most intimately connected, each " beach " having in many localities a " bank " of blown sand a little farther inland behind it, just as the present beach at the north side of the Tyne Mouth is bordered by the long ridge or bank of blown sand called Sandy Hirst. A beach may be easily concealed by recent blown sand, but a bank of the latter is more difficult to destroy, and thus near Ravensheugh Sands, a mile N.W. of Tyne Mouth, the bank of blown sand which was formed when the sea stood 25 ft. higher than at present is still well preserved, though the raised beach contemporaneous with it is very indistinct. This indistinctness is due to the local circumstances : between the beach and the sea lies a mass of shifting sand, which is continually receiving fresh supplies when the tide is out and dry winds are blowing. The 182 Pleistc-certe dild Recent. trace of the even beach line becomes more and mare blurred, while in many eases the bank, arresting the moving sand, tends to grow bigger so long as the fresh supplies last. If, in such a case, the supply- were to be cut off, the bank itself would in time be levelled. The older the beach, the' longer these agencies have had to act, and the more complete their work. Thus the 100-ft. beach in the Gullane area is found on both sides of the road from Gullane to Dirleton under variable conditions. It is quite distinct on the north side of the road from Collegehead west- ward for about a mile. Here it is near the limit of supply of sand, and in consequence is very little blurred in outline ; but, owing to the scanty supply of sand, its bank, standing on a greatly exposed small ridge, has been almost blown away. The boundary of this beach is really the margin of an old flat extending for nearly a mile northwards, and as one goes seaward, toward the source of supply, the old sand banks on it are better and better preserved. The most perfect evidence of the nature of this flat as a whole is afforded by a portion of it that is enclosed within a chain of sand dunes thait com- mence about Eldbottle Brae and extend to the south-west for some distance. It will be noted that the preservation of this encircled flat is most perfect where it is furthest from the fresh supplies of sand, which elsewhere is often blowD on to it. If, now, the form of this be compared with the enclosed flats of the modern beach, such as are so finely illustrated in the Scilly Isles, its original nature as a beach is at once obvious.* On the south side of the road to Dirleton the same beach is again visible, but facing a direction from which little sand was available to cover it or form a bank. It is thus quite clear in the village of Gullane itself, but to be seen properly one must look along its length ; it is clear that the very small bluff behind it can mark but a short period of cessation in the progress of emergence. To the south it gradually enters the area of modern sand supply, and is overblown ; but, to the east, it can be easily traced to a point south of Collegehead, where it abruptly ceases. After puzzling over this strange disappear- ance for some time, the only satisfactory solution that suggested itself was to suppose that the great hollow that stretches across the country from Aberlady to Tyne Mouth was filled with a mass of mud- loaded ice. The terrace was really cat, possibly on both sides of the hollow, but in ice, and when this disappeared, the terrace disappeared also. In some cases the ice in which the terrace was cut was greatly charged with mud and stones, and the terrace lines are preserved, but very faintly, and always at levels below the 100-ft. contour, because on the final melting of the ice which was mixed with the mud, the latter was necessarily dropped to a lower level. Between Dirleton and North Berwick traces of terraces have been met with slightly above the 75-ft. contour, but these are 1 n'ot strictly horizontal, and so interrupted and vague, that we may suppose them to have been cut when a thin layer of ice existed in places. The 75-ft. raised beach is quite well defined for a short distance in the hill face due north of Gullane. A considerable amount of * The most perfect parallel occurs at the south end of Tresco, but an approxima- tion to the same feature is shown in St. Martins. See " Geology of the Isles of Scilly," Mem. Geo!. Survey, 1906, plate vii. Raised Beaches. 183 blown sand occurs on top of the cliffs between the east end of North Berwick and Castleton, which lies about 75 ft. above sea-level ; we have little doubt that it belongs to the period of the 75-ft. beach, though the beach itself is not observed at this locality, having probably- been denuded away. About Seacliff there is another large mass of blown sand near the 75-ft. contour, on top of the cliff. This sand stretches half a mile inland, though there is very little sand on the present shore. It must have gathered when the sea stood about the 75-ft. level, and it is to be noted that it terminates inland so suddenly as to suggest that its further progress was blocked by some barrier that has since disappeared — possibly the remnant of the ice-sheet. The only trace of the 50-ft. raised beach is a faint terrace on the east side of the ridge which extends from Weaklaw, on the coast, to Collegehead. This does not, however, keep strictly, to one level, and seems to mark a slow rise of the land rather than a definite pause in the upward movement. g. b. East of Tyne Mouth. — Between the mouth of the Tyne and Dunbar, there is no erosion feature which can be definitely assigned to the 100-ft., or any beach higher than the 25-ft. If the level plateau, which lies at a height of 75 ft. above O.D. to the west of Dunbar, is a plain of marine erosion, it must be of pre-glacial age, because it has a thin layer of boulder clay over it and because the basaltic crag of Knockenhair * with its " tail " of tuff and boulder clay remains un- modified by marine action. Marine deposits belonging to a period older than the 25-ft. beach are found at Belhaven. Here a blue laminated clay, formerly dug for brick-making, has yielded numerous specimens of Ophiolepis gracilis Allman.j" This brittle-star is known only from late glacial marine clays at St. Andrews and at Montrose. At the latter locality it has been found in association with Yoldia pygmaea (Miinst.), Pecten groenlandicus Lamk., and other Arctic forms. J The Belhaven clay lies only a few feet above high-water mark, and, though its surface formed the sea-floor in 25-ft. times, there can be little doubt that the clay belongs to an earlier period. h. b. m. On the south sides of the mouths of Thornton Burn and Dunglass Burn, there are high gravel terraces which may possibly be referable to the 100-ft. raised beach, but this beach is not distinct anywhere else in the neighbourhood. On the south side of Thornton Burn other gravel terraces are observable between the 25-ft. and the 100-ft. contours, but they cannot be traced far along the sea margin. C. T. C. THE 25-FT. RAISED BEACH. Along the coast eastwards to Aberlady Bay the 25-ft. raised beach can, as a rule, be readily recognised. It is backed b}' a steep bluff eroded in the drift of the low ground, and is only lost sight of where covered by recent blown sand. Oysters and many other species of * Near Winterfield House. ■fProc. Boy. Soc. Edin., 1866, vol. v. p. 101. X " On the Superficial Deposits of the Estuary of the South Esk.' - J. 0. Howden. Trans. Edin. Oeol. Soc, 1870, vol. i. p. 138. 184 Pleistocene and Recent. mollusca have left their shells on the well-marked platform between Aberlady and Longniddry. The fossiliferous deposits are here fre- quently covered by blown sand, which makes an unusually wide spread in the Aberlady Links. c. B. c. In the northern part of the county it is less continuous. It runs along the coast for three miles to the west of North Berwick, and is again seen at Seacliff, but not along the rocky coast in the interval. At the mouth of Feffer Burn it is sharply defined, and can be traced up the Tyne estuary for some distance, although obscured by blown sand at Bavensheugh, as already stated. p. B. Between the mouth of the Tyne and Belhaven Bay is a wide area of low ground, which was covered by the sea in 25-ft. beach times, and is now partly drifted over by blown sand. Sections in Hedderwick Burn show several feet of bedded sand with marine shells resting on an estuarine clay with plant remains. The latter is perhaps an equivalent of the peat below the carse clays of the Forth, and proves that at the time of its formation the relative level of land and sea was almost exactly the same as it is to-day. The sea then rose on the land in this neighbourhood to about 20 ft. above O.D., and, after depositing the marine sand above the clay, and cutting a rock- platform on the open coast, retreated again to its present level. The inner margin of the beach, as shown on the map, is very indefinite between the Tyne and West Barns, but around Belhaven, it is marked by a degraded cliff the foot of which is about 20 ft. above O.D. About 200 yds. south of Belhaven Point the beach gravel, 4 ft. thick, is full of littoral shells, a list of which is given in the appendix. The stone-lined graves which occur in the beach here are Christian, and do not, therefore, afford any clue as to the age of the beach. The beach is not well seen again till we reach Dunbar, where the lower part of the town south of the Old Harbour is built on it. The sand is stated to be 10 ft. thick, and has a bed of gravel at the base, which rests on the rock-platform. h. b. m. Between Dunbar and Linkhead the 25-ft. raised beach is almost continuous, but is sometimes obscured by sand which has blown over, and settled on it in low undulating mounds. Small patches of the beach are again seen between the foot of Dunglass Burn and Reed Point (one-inch map 34). This blown sand covers most of the raised beach between Barness and the mouth of Dry Burn, but does not greatly obscure the land- ward margin of it, and has therefore only been shown on its south eastern side, so as to allow of this margin being mapped. The blowing of this sand in a south-easterly direction has been arrested by the high wall at the cliff top. c. T. c. Blown Sand. The blown sands, whether belonging to the present beach or the raised beaches, have been already frequently referred to. The larger areas make hummocky bare tracts, with fine sea views and bracing air, and those near populous centres, or easy of access, are used as golf links. The famous links of Gullane, North Berwick, and Dunbar are all situated within the area treated of in this memoir, o. t. c. Freshwater Alluvium. 185 Freshwater Alluvium. There is little to be said about the alluvium of East Lothian. All the larger streams, among which the Tyne ranks first, are bordered by stretches of haugh land. The higher terraces in such cases are, doubtless, often of fluvio -glacial origin. Those of Oldhamstocks have already been described, while another interesting series occurs at the junction of the Tyne and Coalstoun Waters. The alluvium occurring along various deserted channels obviously belongs also to this category. The several accumulations of glacial gravels have already been sufficiently described. Of cognate origin are certain patches of lamin- ated clay which here and there collected in hollows of the drift surface, or in ice-dammed lakes. A good example occupies the flat to the west of Whitelaw Hill, while another, which occurs to the north of the railway at East Fortune, has been worked for brick and tile making. g. b., e. b. b. The only examples of post-glacial lacustrine deposits worthy of notice here are two which have been described in the former edition of this memoir. The first one occurs partially infilling the glacial drainage channel north of Balgone House. The following section, as exposed in a sinking made to receive a gasometer, has been recorded by Sir Roderick Murchison : — Modern debris of clay and fragments from adjacent cliff. Black peat, with a few Lymncea in its lower part, 4 to 5 ft., and thicken- ing to 8 and 10 ft. in the centre of the depression. Shell marl with Lymncea ; a few inches thick only on this side of the loch, but thickening towards the centre of the valley. On this rested bones and skulls. Coarse glacial drift, 3 ft. Finely laminated grey sand, 2 to 3 ft. (water beneath). The bones referred to are numerous, and include the remains of red deer, wild boar, aboriginal oxen, horse, etc. etc., in association with human skulls. Professor Huxley examined the bones and skulls, but found nothing remarkable in them. It would seem that, when the narrow valley was occupied by a lake in which Limncea lived, human beings had a dwelling near its edge, and that the bones of the animals they slaughtered were cast into the water. It is evident from the accumulation of peat and soil above them that a very con- siderable period has elapsed since the day of their burial. The other example is situated in a field half a mile east of Brox- mouth. An old fresh- water loch, about 300 yds. long, formerly lay among the mounds of sand and gravel in this locality. The following section of its deposits has been given by Professor John Young : — Thin sandy soil containing beach shells (probably blown sand). Peat 2 to 10 inches in thickness. Marl, white tenacious, consisting almost entirely of Lymncea, Plan- orbis, Pupa, and Cypris. It is divided by short seams of sand and peat. At the wall next the sea a laminated clay underlies the marl ; on the south side, a layer of sand resting on red sandstone. During the re-survey, examples of Limncea and Succinea were found in considerable abundance in the black earth which indicates the site of the loch. c. t. c, g. b. 186 Pleistocene and Recent. Peat. Considerable tracts of the Silurian Uplands are cloaked beneath masses of peat, but the Carboniferous rocks are almost free from this covering. Fala Moss, near the south-east corner of the map, has recently been examined as a typical example. It covers about one square mile, but has evidently at one time had a greater extension. Its surface is quite firm, the moss having shrunk from drainage. It is in most places undergoing slow denudation along its margin, which is frequently raised considerably above the surrounding moorland. The surface of the moss is still covered by a peat-flora t but this has undergone much change through drainage. The dominant plants are Calluna erica and Eriophorum vaginatum with scattered masses of Sphagnum and some Aulacomnium palustre. Empetrum nigrum is not uncommon, but the Vaccinia are either rare or unrepresented. Along its margin the denuded area is undergoing gradual invasion by a thick grassy covering, consisting chiefly of Nardus striata and Juncus squarrosus, and, where the surface is moister, Aira flexuosa and Molinia cerulea. This grassy covering rests on thin peat which has been bared and washed in the process of denudation. Sections show- ing the base of the original undisturbed peat cannot be found, but at one place 12 ft. is exposed in a gully. The upper 9 ft. here consist of layers of Eriophorum and moss, with scattered Calluna. The lower 3 ft. represent a birch forest, some of the stumps being of large size. C. B. C. CHAPTER XVII. ECONOMICS. Coals. calciferous sandstone series. In considering the possibility of finding workable coals of the Sctemerston group in the district south-east of Dunbar, on the north side of the Cove east and west fault, it has to be noted that in Dunglass Dean a smaller thickness of coal-bearing beds has been preserved than On the coast, and that there are no sections which show that good coals were ever well developed on this horizon in this district. At Marshall Meadows Bay (Sheet 34), a few miles north of Berwick-on- Tweed, some coals were formerly wrought, but these seem to have been decidedly inferior to their representatives at Scremerston.* The coal formerly worked near Linkhead appears to be 400 or 500 ft. above the horizon of the Cove coals, and higher than all the beds which are included in the Scremerston group, as defined in Northumberland. It is said to have been mined for a period of 300 years extending up to the beginning of last century, and there has lately been considerable talk of working it again. The greatest thickness proved in a recent bore appears to be 20 ins. An analysis of this coal has been kindly communicated by Mr. James Cleland, and is as follows : — (Gas, Tar, etc. 42 81 1 Volatile Matter . \ Sulprfur 126 4800 (.Moisture . . 393j (Fixed Carbon 43 23 i Coke . . . J Sulphur 137 -52 00 (Ash . 7-401 C. T. C. On the Coalstoun Estate, south of Haddington, a coal was formerly wrought in shallow pits. It is exposed in the burn south of Sanders- dean, where the thickness is two feet, but the quality is very inferior. The position is probably about 300 ft. below the Lennoxlove Limestone (Long Craig Lower). e. b. b. LOWER LIMESTONE SERIES. An old coal pit is reported to have formerly existed about 200 yds. south-east of East Barns, nearly three miles south-east of Dunbar. No indications of an old pit were noticed in this locality, but if the report is true, it may be presumed that the pit was shallow and worked one of the Lower Limestone Coals. c. t. c. * W. Gunn, "Notes on the Rocks about Berwick-on-Tweed," Proc. Bir. Sat. Field Club, 1901, vol. xvi. p. 315. 187 188 Economics. EDGE COAL GROUP. The occurrence and relative position of the lower coal seams of East Lothian has already been discussed in the chapter on the Edge Coal Series. In that chapter reference was made to the prevailing flatness of the strata ; in many parts of the basin the dip never exceeds 6° or 1 in 10. This flatness, and the consequent shallowness of some of the main seams, has had the effect of making the coal-field com- paratively easy to work to those unprovided with modern pumping machinery ; consequently the coal-field was one of the earliest to be opened up in Scotland. Eound Tranent coal has been worked for centuries, and, as a consequence, the Great Seam, and in places some of the lower seams, have been almost entirely exhausted. e. m. a. The most important economic fact made out during the revision of the East Lothian coal-field is the presence of the Edge Coal Seams in a certain area about Port Seton and Cockenzie, at a depth which makes it practically certain that they have not yet been worked, although they could easily be reached by modern mining methods. Along with this field, there is probably a larger unworked area under- neath the sea to the north, and it is known that coals have never been wrought under the sea from this coast except from Preston Links Colliery. It is worth while to note that there are indications of thinning in some of the coal seams as we proceed to the east in this district. This attenuation affects the Five-Feet Seam, and possibly also the Four-Feet. The Great Seam, however, as we have seen, still retains a thickness of 5J ft. near its outcrop to the east of Port Seton, and the Splint Coal seems to be of normal thickness. e.b.b.,e.m. a. In the district east of Dunbar, as has been shown in a previous chapter, a considerable area is occupied by strata belonging to the Lower Limestone group, which underlies the Edge Coal group. The beds which at Barness come above the Barness East limestone — the uppermost limestone there seen — and also the beds which occur, near Broxmouth, above the crinoidal sa-ndstone near the Vaults, probably represent the basal beds of the Edge Coal group. As the dip of the beds is seawards, and the sea shallow,* it seems possible that some coals may outcrop under the sea at a comparatively short distance from the land. The Edge Coals are represented by the Lickar Coals of North Northumberland, and it therefore seems probable that they are represented in this intermediate area also, but it must be remembered that the Lickar Coals are much inferior to those of East Lothian. Between Barness and Long Craig the beds are not much disturbed and dip seawards between 5° and 15°. In the locality near Broxmouth the structure is complicated by some large faults and disturbances, but, owing to the steep or sometimes vertical position of the strata, coal-bearing beds might be reached at a shorter distance from the shore than near Barness. c. t. c. Hauchielin Coal. — The Hauchielin Coal, as has been previously noted, was worked near Pathhead in a position below that of the Splint and Kough. It has been proved to be the same as the Parrot * In the Admiralty Chart (234 new series) the 20-fathom line passes rather more than a mile and a half E.N.E. of low- water mark at Barness. Goals. 189 Seam of Newbattle, but it does not in the area referred to contain any gas coal, but is an ordinary coal from 15 to 18 in. thick. It is also known to occur in the locality where the railway to Ormiston enters the map. There it is 1 ft. 10 in. in thickness, and contains no gas coal. Apart from these two localities the seam is not known to exist anywhere in the district. Splint and Rough Coals. — The Splint and Rough Coals are only being worked at two localities in this district, viz. close to Macmerry and south of Ormiston. At the Montfair Pit, just north of Macmerry, the Splint or Upper Coal is about 2 ft. 6 in. in thickness, the Rough or Under Coal somewhat thinner. The Splint is a fairly good coal, and is used for both household and steam purposes. The Rough Coal is just being opened up, but is said to be at least as good in quality as the Splint. In the district farther south, between Penston and Pencaitland, the Splint and Rough Coals have been worked in former times from a great number of small pits. It is said that the thicknesses vary, and that in some places the Splint Coal alone, and in others the Rough has been worked. The usual thickness of the strata between the two coals is about 16 ft. The two seams were also formerly worked between Seton Sands and the dolerite dyke at Cantyhall. At the Tyneside Pit, about a mile south of Ormiston, both Splint and Rough Coals are being worked. The Splint Coal is mostly sold for household purposes ; and so, also, is the best of the Rough Coal, but the remainder of the latter is used as a steam coal. The Splint Coal is also being opened up at Fleets Colliery, a mile south of Tranent, where it is called Diamond No. 1, and is 2 ft. 10 in. in thickness. It is classed as a second-class household coal. Five-Feet Seam. — The Five-Feet Seam ranks next to the Great Seam and the Splint in importance among the coal seams in this district. At Preston Links the coal, which is there known as the Jewel, is four feet in thickness, and is used partly as a gas-making coal, and partly for steam and household purposes. An average analysis of the seam, by Mr. G. R. Hislop, F.C.S., has been kindly communicated by Mr. James Nimmo, and is here reproduced : — per cent- Volatile matters (containing '45 of Sulphur) . . . . . . 3414 (-Carbon 53"31 j Coke consisting of Sulphur "19 . . .. .. .. 58'41 I Ash 4-91 I Water expelled at 212° Fahr. .. .. .. .. 7 45 100-00 Gas per ton of coal at 60° Fahr. and 30-in. Bar . . . . . . 11,230 c. ft. Illuminating power of gas in standard candles (per London Argand) 20'54 candles Coke per ton of coal .. .. .. .. .. 1306'38 lb. Heating power of 1 lb. of coke (water from boiling point into steam) 12'58 lb. At Tranent the coal is mostly a steam coal. At the Elphingstone Collieries it is somewhat over three feet in thickness, and is used for both steam and gas-making purposes. It is being opened up at Limylands Colliery, west of Ormiston. 190 Economics. Throughout the whole of the western half of the district, the Five-Feet Seam maintains its character as a workable coal. In the eastern part of the district it is much thinner, and is known as the Panwood, as it was not originally recognised that the two coals were the same. It was wrought formerly to some extent under this name at Penston, Fountainhall, and Ormiston. At the first-mentioned place it is 1 ft. 6 in. in thickness, and lies about 15 ft. beneath the Blackband Ironstone, of which an account will be given under a separate heading. Four-Feet Seam. — The Four-Feet Seam at Preston Links is associ- ated with a two-feet seam of fireclay, occurring above the thicker part of the coal, and it is known as the Third Fireclay Seam. The coal, however, apart from the fireclay, is not considered to be work- able, and the seam is no longer wrought in this colliery {see section on Fireclays). Near Tranent this seam is about three feet in thickness without any important parting. Here there are 8 to 15 in. of splint coal, at the base of the seam, which are used for household purposes, the rest serving as a steam coal. An analysis of the coal used for household purposes has been kindly supplied by Mr. T. Waldie (analysts, Messrs. Tatlock and Thomson) : — Volatile matter — per cent. Gas, tar, etc. . . . . . . . . . . . . 35 31 Sulphur . . . . . . . . . . . . . . "44 Water . : . . . . . . . . . . . . 14-80 Total 50-55 Coke- Fixed Carbon . . . . . . . . . . . . 4358 Sulphur . . . . . . . . . . . . . . -42 Ash . . . . . . . . . . . . . . 5-45 Total 49 45 100-00 Heating power of 1 lb. of coal (water from boiling point into steam) . . 6 '75 At the Elphingstone Collieries, and those of the Ormiston Coal Company, the thickness is about the same as near Tranent. At the former it is used as a steam coal, and as a second-class household coal, the household coal forming the lower half of the seam. At Montfair Pit, close to Macmerry, a thickness of 27 fms. of strata have been bored through above the Penston Splint. This thickness includes the Panwood or Five-Feet coal, and it may pos- sibly include the position of the Four-Feet. In this case the seam must have suffered a diminution of thickness, as the thickest coal which could represent it is a seam 1 ft. 6 in. thick, close to the top of the section. Three-Feet Seam. — Next in ascending order comes the Three- Feet Seam. At Preston Links Colliery, which is the only place where it is worked at present, this seam is about 2 ft. 6 in. in thickness, and is used partly for steam coal, and partly for gas-making purposes. Coals. 1 91 At the Tranent and Elphingstone collieries the thickness is about the same, but the coal is not worked in any of these collieries. At the Cockham Pit, north of Ormiston, this coal ranges up to 3 ft. 6 in. in thickness, but it contains two blaes bands, and is not counted a " clean " coal. Parrot Coal. — Next above the Three-Feet Seam comes the Parrot or Gas Coal, so called from the presence of a band of gas coal in the centre of the seam. The whole thickness varies from 1 ft. 6 in. to 2 ft. 6 in. ; the band of gas coal is brownish in colour, and may have any thickness up to a foot. At Preston Links the Parrot seam appears to be present, but without the customary band of gas coal. At the Tranent, Elphingstone, and Ormiston Collieries, however, the gas coal is found, although the seam is not now worked at any of these collieries. The analysis given below has been communicated by Mr. Burt, Manager of the Elphing- stone Collieries. per cent. Volatile matters (containing '40 of Sulphur) . . . . . . 35'03 ( Carbon 5090 j Coke, consisting of- Sulphur "36- .. .. .. .. 57 '47 (Ash 6-21 I Water expelled at 212° Pahr. .. .. .. .. .. 7 '50 100-00 Gas per ton of coal at 60° Pahr. and 30-in. Bar . . . . 10,624 c. ft. Illuminating power of gas in standard candles . . . . . . 24 - 53 Coke per ton of coal .. .. .. .. .. 1287'32 lb. Heating power of 1 lb. of coke (water from boiling point into steam) . . 12 - 25 lb. This seam was formerly a good deal wrought in the district, but this is no longer the case, probably largely owing to the use of ordinary bituminous coals, with enrichment processes, for gas-making purposes, and the consequent decline in price of true gas coal. Splint Coal. — The Second Fireclay Seam of Preston Links is prob- ably the same as the Splint Coal of Tranent. It is not, however, now worked at this colliery (see under Fireclays). The Splint, how- ever, is worked at Bankton Colliery, intermediate between Preston Links and Tranent, where it occurs in two portions, the upper of which is overlain by a thick post of sandstone. At the Tranent Collieries it is four feet thick, and comprises, at the base, a band of household coal from 1 ft. to 18 in. in thickness ; the rest of the seam is steam coal. At the Elphingstone Collieries the Splint is used as steam coal and as second-class household coal. It is here of somewhat greater thickness than usual. At the time of the revision of this area (1904) it was being worked on the stoop and room principle, the " rooms " being in many cases high enough to stand upright in. The Splint Coal is also worked at the Limylands, Cockham, and Meadow Collieries of the Ormiston Coal Company. These are situated to the west, north, and north-east of Ormiston respectively. At the Meadow Colliery, just north-east of Ormiston, a band of gas coal 12 in. thick, occurs in the bottom of the seam. The following analysis of this band of coal has been kindly furnished by Mr. J. Clark, Managing ] 92 Economics. Director of the Ormiston Coal Company (Analyst, Mr. G. R. Hislop, F.C.S,):— per cent. Volatile matters (containing '56 of Sulphur) . . . . . . 41 '95 ("Carbon 45 "77 ] Coke, consisting of- Sulphur "21 [ . . . . . . . . 50'09 Ush 4-11J Water expelled at 212° Fahr. .. .. .. .. .. 7'96 100 00 Gas per ton of coal at 60° Fahr. and 30-in. Bar .. .. 11,205 c. ft. Illuminating power of gas in standard candles . . . . . . 27 "19 Coke per ton of coal .. .. .. .. .. 1122'01 lb. Heating power of 1 lb. of coke (water from boiling point into steam) . . 12'61 lb. First Fireclay Seam. — At Preston Links Colliery, a seam, called the First Fireclay Seam, occurs between the Great Seam and the Splint position. This is probably the same as the Diver Seam of Northfield Colliery (in Prestonpans, just outside the map), and is said to be a very good seam, but it is not at present being worked. It is not known to occur as a workable coal anywhere else in this district. (See section on Fireclays.) Great Seam. — The Great Seam, as before stated, is the highest workable coal, and the thickest seam in the district. At Preston Links Colliery, north-west of Prestonpans, it is 7 ft. in thickness. At this colliery it is used both for steam, for household, and for gas- making purposes. The coal used for household purposes includes, not far from the base of the seam, a band of " clear coal " 9 in. thick, which has a glossy lustre, and can be handled without soiling the fingers. It occurs not only in this colliery, but in Prestongrange Colliery, in one-inch map 32, and at Tranent and Blphingstone Collieries, farther south. At the Tranent Collieries, situated east and south of Tranent, the Great Seam was only about 5 ft. in thickness. Except for the band of clear coal already mentioned, it was used mostly as a steam coal. At the Elphingstone Collieries (Fleets and Howden Pits, situated respectively to the north-east and south-east of Elphing- stone) the Great Seam is 7 ft. thick. The band of clear coal is present here as usual, and is classed as a first-class household coal. E. M. A. The most important area of the Great Seam which still remains unwrought upon the mainland is that which underlies the Millstone Grit and Coal-measures about Cockenzie and Port Seton. Unfortun- ately, it has not been found possible to determine the boundaries of these formations with any great degree of accuracy, except in the neighbourhood of the coast. At Port Seton, where the seams of the Coal-measures are present, the Great Seam must be about 1100 ft. below the surface. At some old pits near the outcrop of this coal to the east of Port Seton, the seam is known to have had a thickness of 5£ ft.* It is, therefore, almost certain to retain a good thickness throughout the unwrought area. e. b. b. * This information has been kindly supplied by Messrs. Miller, Williamson, & Robertson, Mining Engineers. Coals and Fireclays. 193 At Preston Links Colliery, the dolerite dyke, which, as shown in the map, runs along the shore from Port Seton to Cockenzie Harbour, was formerly the northern limit of the workings in this seam. In the recent reopening of this colliery, however, the dyke has been pierced, and the Great Seam has been found dipping gently out to sea on the northern side. Thus there must be an unworked area underneath the Firth of Forth, in continuity with the land area which has just been mentioned. e. m. a. COAL-MEASURES. The small area of Coal-measures on the mainland at Port Seton has probably been wrought out more or less completely in the old times. But a glance at the Geological Survey one-inch maps 32 and 33 shows that it is highly probable that the Coal-measure seams, like the Great Seam of the Edge Coal group, have an extension to the east- ward, round the end of the Roman Camp anticline, and that they may occur under the sea off the East Lothian coast. Moreover, as Milne Home has emphasised,* the predominant faults in the Lothian basins throw down to the north, while along the southern shore of Fife the majority of the faults downthrow to the south, facts which favour the idea of a large extension of Coal-measures under the Firth of Forth. It is satisfactory, then, to know of two good coals, between six and seven feet in thickness, near the base of the Coal-measures at Port Seton. It is, also, a favourable feature that the interval between the lower of these seams and the Great Seam of the Edge Coals is only 1000 ft., little more than half of that found in the west of the Mid- Lothian basin. E. b. b. Fireclays. As has been mentioned in the section dealing with coals, three coal seams at Preston Links Colliery, north-west of Prestonpans, have fireclays associated with them. These coals are (1) the First Fireclay Seam, corresponding to the Diver Seam of Prestongrauge and Northfield Collieries, in one-inch map 32, and occurring between the Great Seam and the Splint ; (2) the Second Fireclay Seam, corre- sponding most likely to the Splint of Tranent, and (3) the Third Fireclay Seam, which is probably the Four-Feet. All three were formerly worked, but especially the First Fireclay Seam. It consists of 2 ft. of fireclay underlying about 2 ft. 2 in. of coal. The Second Fireclay Seam consists of 2 ft. 6 in. of dark fireclay underlying 2 ft. 2 in. of coal. The Third Fireclay Seam consists of 2 ft. of dark fireclay overlaid by 9 in. and underlaid by 2 ft. 2 in. of coal. The fireclay in connection with the first of these seams does not seem to be very persistent, as there is no fireclay underneath the Diver Coal either at Northfield or Prestongrange. The Second Fire- clay Seam, however, is the same as the Clay Seam of the two last- mentioned collieries, and is underlain in both by 2 ft. of fireclay. A hard fireclay, a foot thick, underlies the Splint at Tranent, but it is not worked. * "Memoir on the Mid-Lothian and East Lothian Coal-Fields," 1839, p. 20. 13 .194 Economics. No fireclay in the position of that which was worked in the Third Fireclay Seam appears to occur anywhere else than at Preston Links. These seams were wrought by Mr. Grieve, owner of the former Bank- park Fireclay Works. Some fireclays — said to be above the Great Seam — were also wrought from a pit quite close to these works, and west of Tranent. It is interesting to note that fireclays in somewhat the same position, namely, above the Great Seam, and a little below the Index Limestone, were worked some miles farther west at Joppa Quarry. Nearly all the fireclay produced at the two centres was utilised in the Bankpark Fireclay Works, where it was manufactured into firebricks, pipes and, gas retorts. The industry was discontinued about thirty years ago. It is stated that a little fireclay has been worked along with the Three-Feet Coal in the pits of the Ormiston Coal Company. The Millstone Grit, which is so rich in fireclays in the West of Scotland, also contains, near Port Seton, seams of marl or fireclay, but no attempt has been made to work them, so it is doubtful whether they are of any value. A seam of fine white fireclay was exposed in the same series, when the mineral railway to Preston Links Colliery was in course of formation, at a point half a mile east of the east end of Prestonpans, but it does not appear to have exceeded a foot in thickness. E. m. a. Black-band Ironstone. At the old Dolphingstone Colliery, a mile and a half west of Tranent, and just outside one-inch map 33, a black-band iron- stone, consisting of 10 in. of ironstone, with a mixture of impure gas coal, was worked about five fathoms above the Jewel or Five- Feet Coal. A black-band ironstone in the same position was wrought near Penston under the name of the Penston Ironstone, where it was 1 ft. 2 in. in thickness, and lay about 15 ft. above the Five-Feet Coal, there known as the Panwood. The following is the section formerly exposed : — Section of B.B. Ironstone and Panwood Coal at Penston. B.B. Ironstone Grey fakes Fakes and blaes (shale) Coal Grey fakes . . Blaes Ironstone band Daugh Blaes Grey fakes . . Sandstone Fakes and fireclay Daugh Foul Goal (Panwood or Five-Feet) The output of ironstone was at one time as much as 100 tons a day, but it ceased to be worked in this district in 1880. It is not known Ft. in. 1 2 8 10* 7* 5 11 1 n 4 23- n 1 3 9 1 11 0i 1 6* Metalliferous Veins and Building Stone. 195 to have been worked north of the road leading from Edinburgh to Haddington, and seems to die out in that direction.* This band of ironstone has been proved at Fountainhall and Ormiston, where it is also found in connection with the Five-Feet Coal. It may be represented near Elphingstone by a thin seam of coal ; otherwise, it would seem to be absent from the central part of the East Lothian basin. e. m. a. Other Minerals. A mine for haematite was formerly wrought by the Coltness Iron Company, a little to the south-east of the Hopetoun Monument. The vein, which cut through trachytic lavas, had a N.N.W. strike, and was nearly vertical. Three shafts were sunk, and the workings were carried to a depth of at least 250 ft. Many years ago J. W. Young analysed two specimens of the ore,")" one of which yielded 89"64 per cent, of peroxide of iron, and the other 89'28 per cent. A boring which was put down for water subsequently, in 1892, about 200 yds. E.N.E. of Blackmains, cut another seam of haematite at 18 fms. The thickness recorded in the bore journal is two feet, but in this allowance must be made for the inclination of the seam, which has not been determined. It is stated that trials for haematite were formerly made in the Upper Old Red Sandstone on the south side of the road about 200 yds. W.N.W. of Oldhamstocks Bridge, but they evidently did not meet with much success. Crystals of galena are occasionally seen in the vein in the limestone quarry at Catcraig, east of Dunbar, and in little strings in the dolerite dyke near the White Sands, but they are far too rare to be of economic value. In the last edition of this memoir J Sir A. Geikie made the follow- ing reference to veins of ore in the old tableland of the Lammermuirs. Veins of barytes containing copper (" green carbonate and prismatic copper glance," according to Cunningham) have been worked to a small extent in the Priestlaw granite. Ores of the same metal have been found in small quantity in other parts of the Lammermuirs in lodes that run with the strike of the strata. These have been indi- cated by gilt lines. Building Stones. old red sandstone. A considerable part of Dunbar is built of a deep red sandstone, which has, no doubt, been obtained from the Old Red Sandstone areas adjoining the town. The sites of several old quarries, which formerly supplied such stone, are still distinct in the cliffs west of the town, and also near Bourhouse and Wester Broomhouse. In the last-named * The above information has been kindly supplied by Mr. R. Moore, Smeaton Park, Inveresk. t Trans. Glasg. Oeol. Soc, vol. iii. 1871, p. 373. % Geology of East Lothian, p. 17. 196 Economics. locality a quarry is still being worked, at the west end of which we find about 25 ft. of Indian red sandstone of medium or somewhat coarse grain, often somewhat calcareous, and occasionally mixed with galls of clay shale. In the area of Upper Old Red Sandstone, which extends from this locality nearly to Gifiord, numerous small quarries have been opened up to meet local demands : the stone is much jointed, and not durable, and so is never used very far from the quarries. CALCIFEROUS SANDSTONE SERIES. Sandstones have been wrought in the upper part of the Calciferous Sandstone series at Eentonhall, south-east of Haddington, and other localities. Sandstones above the volcanic rocks are quarried to some extent in the Gullane area, mostly to the west of the town ; but the rock is not sent far from the district. Its somewhat calcareous character detracts from its durability, but probably less so in a rural district than it would in a manufacturing town. On the eastern margin of the one-inch map 33, the Bilsdean sandstone is exposed for a con- siderable distance along the shore, and in Dunglass Dean, and it was once largely quarried in the latter locality. It furnished the stone of which Dunglass Mansion House was built, about a hundred years ago, and makes an excellent building stone, mostly of a white or pale yellow colour, which is very easy to work, and yet durable. The thick red sandstones near Branxton and Thornton have also been formerly wrought. C. t. c, g. b., e. b. b. EDGE COAL GROUP. In the Tranent neighbourhood several quarries either have been or are now worked for building stone on a horizon somewhat above the Great Seam. To the west of Tranent two sandstones are quarried in this position, the lower one coarse and gritty and white in colour, the upper one brown and with numerous plant remains. They are separated by a few feet of unworkable strata containing a thin coal. Near Bankton a white sandstone, 40 ft. thick, is quarried on a somewhat lower horizon, namely, just above the upper division of the Splint Coal. Near Winton Castle and Wintonhill farm there are some old quarries in a sandstone which occurs about 15 or 18 fms. above the Splint and Rough Coals, and probably just above the position of the Five-Feet Seam. This sandstone varies in grain from medium to very coarse, and the finer part has been used for building stone. In at least one place, however, the bed is so much decomposed that instead of being quarried it has been carted away as building sand. E. M. A. IGNEOUS ROCKS. The igneous rocks which are used for building stone include porphyritic basalts of the Markle type, porphyrinic trachytes, and the phonolitic trachyte of North Berwick Law. The first type has been extensively quarried in the district west of East Linton, and is used in East Linton and in Dunbar. The town of Haddington is largely Building Stone, Sand, and Limestone. 197 built of a porphyritic trachyte obtained from Peppercraig Quarry, a little to the north of the railway station, and a porphyritic quartz trachyte has been quarried to a small extent at Dirleton Craigs Quarry, west of Dirleton. The rock of Traprain Law (trachytic phonolite), though quarried very largely for road metal, is rarely, if ever, used for house building. The rock of North Berwick Law (phonolitic trachyte), however, is almost useless for road metal, but on the other hand is quarried to a great extent for building purposes. This is due to the fact that it is not fresh and hard like the Traprain rock, but owing to decomposition has acquired a particularly rich red-brown tint, and can be freely worked, though still retaining considerable coherence. The greater part of North Berwick is built of this rock, and its dis- tinctive rich colour adds a charm to the place. g. b., e. b. b. Sand. Important accumulations of glacial sand and gravel extend along the flanks of the Lammermuir Hills and along the coastal plain east of Dunbar, and are found also in other situations. They have been opened up for local purposes in numerous small pits. As noticed in the previous section, building sand is also obtained near Winton Castle from a soft decomposed sandstone, probably just above the position of the Five-Feet Coal. Limestones. calciferous sandstone series. Two limestones at the base of the volcanic group, namely, the Sunnyside Limestone near Traprain Law, and the Bhodes Limestone near North Berwick, have been quarried for burning and for the building of walls. The Rhodes Limestone is said to be of excellent quality. g. b. LOWER LIMESTONE GROUP. The limestones of the Lower Limestone group have been or are being wrought in this map in both the areas in which they occur ; that is, east of Dunbar and in the belt which borders the East Lothian coal basin. In the Dunbar district the Skateraw Middle Limestone has formerly been extensively quarried at Skateraw, Catcraig, and Oxwell Mains. At the time of the resurvey it was still being worked at the last locality, and 30 or 40 tons a day were being obtained. Of this, two-thirds were sent to the West of Scotland for smelting purposes, while the other third was burnt into lime, chiefly for agricultural purposes, in the adjacent kilns. The top band — the ferruginous crinoidal band which comes above the Saccammina band — was not burnt, but the rest is said to be a very pure limestone, yielding a first-class lime. The Longcraig Upper and Middle Limestones have both been •quarried near the Dry Burn, and the former on the shore also, near 1 98 Economics. Catcraig. The Chapel Point Limestone is sometimes quarried on the shore at Chapel Point, but only on a small scale and for road metal. (See section on Road Metal.) c. t. c. Along the belt of Lower Limestones which extends from Aberlady to Pathhead the limestones have been worked in numerous quarries in former times, though only one quarry, namely, Harelaw Quarry, east of Longniddry, is open at present. The greater number of these quarries are probably in two bands of limestone, which are taken to be the Longcraig Upper and the Skate- raw Middle. The former is the one being worked at Harelaw Quarry. Analysis has shown that the limestone of this quarry contains 96 per cent, of carbonate of lime. The lime is used for building, plastering, agricultural, and gas purifying purposes. The same limestone was worked in several old quarries near Harelaw Quarry and west of Setonhill ; also at the Landridge Quarry near Redcoll and at Salton Quarry near Middlemains. The last-mentioned quarry also worked a higher band of limestone which is probably the Skateraw Middle. The Skateraw Middle Limestone was also worked at an old quarry in connection with the Jerusalem Lime Works ; at the Spilmersford Quarries east of Pencaitland, at the Lampland Quarries near East and West Peaston, and at the quarries on the main road about a mile south-east of Pathhead. (See section on Lower Limestone group.) c. b. c. Road Metal.* The following list shows the quarries in one-inch map 33 from which road metal is being or has been obtained. Those no longer used are marked by an asterisk : — SEDIMENTARY ROCKS. Silurian Qreywacke. 1. Soutra Hill Quarry, N. side of Soutra Hill. 2. Blegbie Quarry, near Blegbie, 3 miles E. of Fala. 3. Hornshill Quarry, S. of Snawdon, 3 miles E. of Gifford. 4. Clints Quarry, S. of Moorcock Hall, 2 miles S.E. of Garvald. 5. Pathhead Quarry, near Pathhead, 2 miles S.E. of Stenton. Carboniferous Limestone. 6. West Peaston Quarry,* S. of Pencaitland. 7. Quarry at Chapel Point, 4 miles E. of Dunbar. IGNEOUS ROCKS. Lavas and Intrusive Rocks of Lower Carboniferous age ; given in approximate order of decreasing basicity. 8. Chesters Quarry, S. of Whitelaw Sill of Monchiquite. Hill, near Chesters. 9. Baro Quarry, in plantation S. of Sill of Analcite Basalt (very closely Baro, 2 miles N.E. of Gifford. allied to 8). * Thanks are specially due to Mr. T. Callen and to Mr. P. Clarke, C.E., Road Surveyors of the Western and Eastern District of Haddingtonshire respectively, for the technical information contained in this section. Road Metal. 199 10. Kidlaw Quarry, 3 miles S.W. of Sill of Analcite Basalt. Gifford. 11. West Fenton Quarry, near Peffer Intrusion of Analcite Basalt. Burn, S. of W. Penton. 12. Gosford Bay Quarry. Sill of Olivine Analcite Dolerite, or Teschenite. 13. Galalaw Quarry,* in eastern of Intrusion of Teschenite. the two intrusive masses S.W. of Gullane. 14. Traprain Law Quarry. Laccolite of Trachytic Phonolite. 15. Skid Hill Quarry, just south of Quartz Banakite. ? Lava. Garleton Castle, and 1J miles N. of Haddington. 16. Bangly Quarry, near Bangly Quartz Banakite. ? Lava. Braehead, 2 miles N.W. of Haddington. 17. Peppercraig Quarry,* a little N. Porphyritic Trachyte. of Haddington Station. 18. Pencraig Quarry, on main road Laccolite of Trachyte. 1 J miles W. of East Linton. 19. Dirleton Craigs Quarry,* just W. Quartz Trachyte. of Dirleton. Intrusions supposed to be of late Carboniferous age. 20. Millstone Neuk Quarry, 2 miles East and west Dolerite dyke. E. of Dunbar. 21. Quarry near Seton West Mains, East and west Dolerite dyke. S. of Cockenzie.* The outside quarries, material from which is used within this area, are all in the adjoining one-inch map 32. The following is a list of these quarries : — Ravelrig Quarry. "I Sill of Olivine Dolerite of (?) early Kaimes Quarry. J Carboniferous age. Ratho Quarry. Sill of Quartz Dolerite of late Car- boniferous age. Westcraig Quarry. 1 Sill of Quartz Dolerite of late Car- Lenny Quarry. J" boniferous age. The largest sources of supply for the district as a whole are Traprain Law, and the Ravelrig and Kaimes Quarries. The Silurian greywackes yield a rather soft stone, which is only used locally ; the Pathhead stone, for instance, is variable in char- acter ; it gives a good summer surface, but one which in winter is apt to be spoilt by intermittent frosts. The Chapel Point limestone quarry is on the seabeach, and can only be worked at certain states of the tide ; the stone is used for roads which have not a heavy traffic. The Chesters Quarry stone (monchiquite) is a first-class stone for road purposes, but hard to quarry and break. It is inclined to be " knobby " after lying on the road for a couple of years, and forms a slippery surface on slopes. Baro Quarry (analcite basalt) furnishes a useful stone very suitable for roads in the neighbourhood. Although a heavy stone, it is a little " dead," and inclined to be muddy. It lies well and gives no trouble by working loose. It is not slippery, and is very suitable for slopes. Although closely allied to the stones from both Kidlaw and Chesters Quarries in mineral composition and texture, its behaviour is markedly different from that of either. Kidlaw Quarry (analcite basalt) furnishes a first-class stone which wears well and forms the minimum of mud. It stands heavy traffic 200 Economics. well, and weather has little or no effect upon it. Though inclined to work loose in dry weather, it does not get " knobby " like the Chesters Quarry stone, and is not so slippery on steep gradients. West Fenton Quarry (analcite basalt), in the southern of the two intrusive masses occurring near West Fenton, furnishes a fairly good but somewhat soft stone. It makes a good running surface during the summer, but is inclined to form a muddy surface when there is heavy traffic during the winter months. Gosford Bay Quarry (olivine analcite dolerite or teschenite) furnishes the best material in the western part of the sheet, but it is a tidal quarry, and cannot be worked at all states of the tide. The stone is neither too hard nor too soft ; it stands all kinds of traffic well, and forms very little mud. Galalaw Quarry (teschenite) is now disused ; when worked it fur- nished a soft stone which crumbled very readily. This may be due to its coarse texture and the abundance of analcite. Traprain Law Quarry (trachytic phonolite) gives the largest supply of road metal in East Lothian. The rock is very hard and brittle, and difficult to work ; in the quarry it has a very high working face — about 200 ft. Great care has to be exercised in breaking the stone, owing to the brittleness of the material, and it lacks the degree of toughness which is characteristic of good road metal. Its wearing quality is inferior, and the surfaces of roads on which it is applied are of an open brittle character, especially during the summer-time. It gives a good surface, free from mud, during the winter-time, but taken as a whole the stone is certainly not of the best quality. Skid Hill Quarry (quartz banakite) furnishes a variable stone ; the best parts having been mostly quarried out, the material now got is second-class. The same remarks apply to Bangly Quarry (also quartz banakite), where the stone now got is inferior, although it is supposed that there may be better material still unworked. Pen- craig Quarry (trachyte) yields a soft stone which is principally used on roads which are badly wind-swept, as it gives a very close surface. Dirleton Craigs Quarry (quartz trachyte) yielded an inferior stone, and was abandoned about ten years ago. Coming to the intrusions of later Carboniferous age, that quarried at Millstone Neuk (quartz dolerite) yields an excellent stone which for surface and wearing qualities is hard to beat. It is, however, only possible to get the material at low-water spring tides. The quarry in the east and westerly dyke near Seton West Mains did not yield so good a stone, although it belongs to the same general petrological type. It was soft and unable to stand heavy traffic, and, as quarry- ing was rendered difficult by water finding its way in from old coal- pits to the south, the quarry was abandoned. Another old quarry in the same dyke exists to the south of Longniddry. The Road Surveyor of the Western District of Haddingtonshire makes the following comparative estimate of the qualities of the road metals used in that part of the county : First of all comes Gosford Bay Quarry (olivine analcite dolerite or teschenite), then Kidlaw and Chesters Quarries (analcite basalt and monchiquite), then Traprain Law (trachytic phonolite) in the Eastern District, while last among the igneous rocks come Skid Hill and Bangly Quarries (quartz banakite). The Silurian greywackes come about last in the list. It will be seen that on the whole the more basic igneous rocks are the best, the Road Metal and Agriculture. 201 more acid types being of inferior quality. This rule also holds good in the eastern part of the sheet, where the Millstone Neuk rock (quartz dolerite) heads the list. Traprain Law (trachytic phonolite) is not nearly so good, while the material from Pencraig Quarry (trachyte) is of inferior nature. It will be seen, however, on reading over the descriptions given above, that the properties of the stones are not wholly dependent on their petrological characters, so far, at least, as they can be studied under the microscope. Some other cause of variation must be present, as in the case of Baro Quarry stone, which in road-making qualities differs widely from the stones from the Chesters and Kidlaw Quarries, although very like them in microscopical characters. The sill of porphyritic basalt, about two miles west of Fala, is in very sound condition, and might advantageously be tried for road metal, being near the main road from Edinburgh to Lauder. E. B. B., E. M. A. Agriculture. Taking the district as a whole, it may be said to be divided into two by the boundary fault of the Southern Uplands, which runs across the map from south-west to north-east. To the north-west of this fault the country is mostly occupied by sedimentary strata of Old Red Sandstone and Carboniferous age, together with volcanic rocks of the latter period, as has been described in previous chapters. On the whole, these rocks give rise to low-lying country, the greater part of which is cultivated as arable land. To the south-east of the fault, the Silurian strata, as well as the Old Red Sandstone conglomer- ate, with which they are sometimes covered, form a more elevated tract, which is mostly hill pasture used for sheep grazing. An area of cultivated ground occurs, however, at the south-east corner of the one-inch map 33, and another, along the coast south-east of Dunbar, where rocks of Carboniferous age are again found. The greater part of the Lammermuirs is heather covered, and most of the sheep supported on them belong to the blackfaced stock. The arable ground within the map may be roughly divided as follows : (1) tracts where drift accumulations are thin or absent ; (2) tracts with a sandy subsoil ; and (3) tracts where the subsoil is boulder clay. Under the first heading come some areas in the Garleton Hills. The danger to cultivation in areas of this sort lies in the liability to parching in times of drought. Among areas which may be included under the second heading comes the long belt of glacial gravels and sands which flank the Lammermuirs through a great part of the district, and turn round to the south-east a little south of Dunbar. These gravels are all cultivated. The gravelly lands of Cockburnspath and Innerwick, merging into the mellow loamy soil of Dunbar, are also formed of glaciai deposits of similar character to those last described. They occur at a lower level, and have long been noted as the finest potato-lands in the kingdom. Another type of ground with a sandy subsoil is formed by the accumulations of blown sand and raised beach deposits which border some parts of the coast. Near Prestonpans the raised beaches have a rich sandy soil, and are used largely for market gardens. 202 Economics. The greater part, however, of the arable land has a subsoil of boulder clay, the nature of which varies with that of the underlying rock, though it is influenced also by the nature of the rock to the west of its place of occurrence, as the ice in this area advanced from west to east. In the district to the south of Haddington it is of a somewhat lighter nature than usual, owing to the predominance of sandstones in that district. The tract of Old Eed Sandstone between Gifford and Dunbar is also covered by a very sandy boulder clay derived from the subjacent rocks. In the area between Haddington and North Berwick, the boulder clay represents the churned-up debris of limestone, sandstone, and shale, with a large addition, in many cases, of volcanic material which adds greatly to the fertility of the soil. The farmers have taken full advantage of the rich nature of the land, and have turned this into one of the best farmed districts in Scotland. With the growth of Edinburgh, North Berwick, and Dunbar, a demand has sprung up for fresh vegetables, which are now largely cultivated. Water Supply. The Silurian rocks which form a great part of the south-eastern half of the one-inch map 33 are almost impervious to water, and the rain which falls over this area runs off in the form of streams, which may be collected into reservoirs, as is being done at Castle Moffat, above Garvald. The sedimentary rocks of Old Red Sandstone age, and the sedimentary and igneous rocks of Carboniferous age, which occupy the remainder of the area being described, are on the other hand more or less pervious to water, and the result is that a certain part of the drainage is underground. This makes it possible to obtain water in some localities by means of bores ; it also gives rise to numerous natural springs, which have been utilised in many cases to provide a supply of water. Besides these more solid rocks, the glacial sands and gravels which occur so extensively along the flanks of the Lammer- muirs and elsewhere are often water-bearing, and where a bed of gravel rests on boulder clay the junction is often marked by a line of springs. We shall consider the different towns and districts briefly with regard to the sources of their water supply. In the Bast Lothian coal basin, extending from Prestonpans to Pathhead, a good deal of the surface water finds its way into old or present workings for the ex- traction of coal. From these it is either pumped out, to find its way along the surface towards the sea, or in one or two cases, as in an old level which leads northwards from the Tranent Colheries, a certain amount of drainage actually takes place in underground tunnels. At present, underground water of this sort, procured from some workings near Bankton, is being utilised to form a temporary supply to the town of Prestonpans. To provide a permanent supply a reservoir has been constructed at Kidlaw, about three miles south- west from Gifford, with a catchment area on the Silurian rocks, but repeated difficulties have been experienced in forming this reservoir. A bore which was put down proved deceptive, having probably come on a large boulder in the drift itself, and consequently it was found Water Supply. 203 necessary to sink much deeper than had been expected to obtain a foundation for the retaining wall of the reservoir. When ready this source is intended to supply both Prestonpans and the neigh- bouring village of Cockenzie.* Tranent, Ormiston, and Blphingstone are supplied from a locality about a mile south of Pathhead. While considering this district, it may be of interest to point out the existence of a sandstone at least 20 fms. thick, which has been met with in some bores to the north of Tranent. Its upper surface lies about 70 fms. below the Great Seam, and 15 fms. below the horizon of the Splint and Rough Coals. This sandstone might yield a good water supply if it persists to an outcrop on either side of the basin, without interruption by any large faults, but unfortunately our knowledge of the district does not allow us to state definitely whether it does so or not. It should also be said that if it were to be bored to for water in the central part of the basin, difficulty would be experienced from coal wastes which the bore would be almost certain to penetrate before reaching the sandstone. The Millstone Grit of the northern portion of the basin might also possibly be water-bearing, if bored at the right place. E. m. a. Aberlady has a gravitation supply from three small sources- wells or springs — on the farms of Byres, Ballencrieff , and Ballencrieff Mains, the two former at any rate being in the volcanic area. At the time of the revision of this area Gullane was supplied with water from two bores close to the town. One of these is situated a little less than half a mile from high-water mark ; it starts from about 100 ft. above sea-level, and goes down to a depth of 214 ft. in sedimentary rocks. The other is rather more than half a mile from high-water mark ; it starts from between 100 and 200 ft. above sea-level, and goes down 300 ft. through sedimentary rocks and a sill of whinstone. For a time these bores yielded a supply of fresh water, though not very copious, but latterly the water in both has become contaminated. In the first bore this is almost certainly due to the infiltration of sea water. The strata, as well as the sill of whinstone, dip to the west, and strike seawards. The water supply of Haddington is obtained chiefly from springs issuing at the base of the monchiquite sill of Chesters Quarry, a mile to the west of Garvald. The sandstones furnishing the supply are of Upper Old Red Sandstone age. One of the most striking glacial dry valleys of the district cuts through the sill and so enables the water beneath it to be easily tapped. Haddington has, also, an additional supply from the glacial gravels near Long Yester, two miles to the south of Gifford. North Berwick was originally supplied by small springs near the Law, some of which are still utilised. A larger supply of excellent water is now, however, obtained from two reservoirs near Garvald, with a catchment area which is mainly Silurian. One of these, which is shown on the map to the south of Carfrae, is in a glacial drainage valley. The water is led into North Berwick in a six-inch pipe, some farmhouses being supplied on the way. Only a small proportion of the rainfall of a district will, as a rule, percolate underground if a thick cover of boulder clay be present, for it acts as a more or less impervious layer. The volcanic rocks in the * The supply from Kidlaw reservoir has now been introduced into Prestonpans. 204 Economics. northern part of the sheet have large outcrops bare of boulder clay, and they would no doubt carry much underground water if they were as pervious as sandstones. Water does, indeed, enter these rocks, but chiefly by means of cracks and joints, which become less and less open the deeper they are beneath the surface. This makes the rinding of water by bores and wells very largely a question of chance ; if a well be ortunately sunk about a network of joints a considerable quantity may be obtained ; but if not, the supply will be little or none. This is illustrated by two borings in the volcanic series which have previously been referred to. Taking first that at North Berwick, the amount of water obtained was singularly small, when we consider that the bore reached the sandstones and shales below the volcanic rocks. On the other hand, the bore at Seacliff had the luck to tap what was called a spring, clearly a shatter or joint zone, a considerable distance above the position of the bottom of the North Berwick bore ; and in this case water rose to a considerable height in the bore. G. b., e. B. b. Dunbar is supplied by a reservoir on the Spott Burn near Little Spott. This is in a glacial drainage valley, and the catchment area is mainly occupied by rocks of Old Bed Sandstone age. A boring recently made near high-water mark at Catcraig went down 365 ft. below the base of the Longcraig Lower Limestone. It yielded a good supply of water, which spouted from the mouth of the bore hole at the rate of about 160 gallons a minute.* A thick sandstone, with its surface about five feet below the limestone, was met with in the bore, and it was from this sandstone that the water was derived. It is probably of general occurrence in those areas where the overlying limestone exists, and it might be worth while to bore down into it in various localities on the chance of obtaining water. At Lennoxlove, near Haddington, the sandstone, 37 ft. thick, below the limestone outlier, yielded water ; but, after passing through 153 ft. of marls and fakes, a lower sandstone, 62 ft. thick, was reached, which was quite dry. Cockburnspath and Oldhamstocks, and many of the adjacent farms, are supplied with water piped from springs some distance away, some of which come from beds of glacial sand overlying the boulder clay. c. t. c, e. b. b. * This is an estimate made by Mr. W. Meek, who furnished us with the journal of the bore. In the summer of 1907 the yield was estimated at 1Q0 gallons a minute. APPENDIX. PACtE I. PaLjEONTOLOGICAL — Prefatory Note. By Dr. Lee . . 206 A. Lists of Fossils in Special Localities ... .207 B. Note on the Fossils collected from the Shales in " Cheese " Bay, on the Shore about two miles north-east of Gullane, East Lothian. By Dr. Peach 215 C. Vertical Distribution of the Carboniferous Fossils. By Dr. Lee ... . . . 217 II. Bibliographical — List of Writings descriptive of the Geology of the Area included in the Memoir. Compiled by Mr. David Tait . . 218 206 Appendix. I. PAL^ONTOLOGICAL. The greatest number of the fossils given in the following Lists were collected by the late Mr. Bennie, whilst a few were lately added by Mr. A. Macconochie and Mr. D. Tait. Some of the specimens obtained in earlier years were determined by Mr. E. Etheridge, junior, and the study of special groups has been kindly undertaken by the following specialists : The Fishes, the higher Crustacea, the Plants, and the Lamellibranchs were determined by Dr. Traquair, Dr. B. N. Peach, Dr. R. Kidston, and Dr. Wheelton Hind respectively. Dr. C. B. Crampton has named some of the Brachiopoda. Professor T. R. Jones and the late Mr. Kirkby determined the Entomostraca, and the late Mr. H. B. Brady named the Foraminifera. The nomenclature of the Bryozoa, Brachiopoda, and Gasteropoda has been revised by Dr. G-. W. Lee. The Lists have been drawn up by Mr. A. Macconochie, under the superintendence of Dr. B. N. Peach. G. W. Lee. Palceontological. 207 A. LISTS OF FOSSILS IN SPECIAL LOCALITIES. Calciferous Sandstone Series. Shore £ ml. and 50 yds. E.S.E. of entrance to Cove Harbour (one-inch map 34). Cementstone bands in the Cementstone Group. Cardiopteris sp. Lepidodendron sp. Lepidostrobus sp. Lepidophyllum sp. Cordaites sp. Stigmaria fiooides undulata Gopp. Brongt., var. Spirorbis pusillus (Mart.). sp. Glyptoscorpius oaledonicus (Salt.). [Cycadites auct.] Sanguinolites abdenensis .B. Eih., jun. Sohizodus sp. Cheese " Bay, on shore 2 mis. N.E. of Gullane. Soft dark shale, oil shale, and cement band. Above the Traps. Cardiopteris frondosa (Gopp.). Sphenopteris foliolata Stur. obovata L. & H. Spiropteris sp. Telangium affine (L. & H.). [Calym- matotheca auct.~] Telangium bifidum (L. & H.). [Calym- matotheca auct.~] Lepidophloios scoticus Kidston. Lepidophyllum lanceolatum L. & H. Lepidostrobus comosus L. & H. fimbriatus Kidston. sp. Leaia leidyi var. salteriana Jones. Tealliocaris loudonensis Peach. woodwardi (B. Eih., jun.). [Anthrapalsemon auct.~\ Eoscorpius sp. Prestwiehia sp. Anthracodesmus sp. Acanthodes sp. Coelacanthus sp. Gonatodus punctatus Ag. Elonichthys robisoni (Hibbert). striatulus Traq. striatus Ag. Nematoptychius greenocki (Ag.). Rhadinichthys brevis Traq. elegantulus Traq. formosus Traq. ornatissimus (Ag.). Rhizodus hibberti (Ag. <£• Hib.). Wardichthys cyolosoma Traq. Shore a little below high-water mark 90 yds. S. of entrance to Cove Harbour. Shale crowded with Cardiopteris. Below the Cove Lime- stones. Cardiopteris polymorpha (Gopp.). Rhodea moravica (Ett.). Lepidodendron sp. Shore 66 yds. S. of the middle of the entrance to Cove Harbour. Cove Lower Limestone. Crhioid remains. Productus sp. Spinier sp. Edmondia rudis (M'Coy). Modiola macadami (Portl.). Pinna flabelliformis (Mart.). mutica M'Coy. Sanguinolites plioatus (Portl.). Bellerophon hiulcus (Mart.). 208 Appendix. Shore at low-water mark 220 yds. E. by N. of Linkhead. Limestone and limy shale. The Linkhead Lithostrotion junoeum (Flem.). Syringopora sp. Archseocidaris urei (Flem.). sp. Crinoid stems. Spirorbis sp. Eenestella sp. Dielasma sacoulum (Mart.). bratula auct.~\ Lingula squamiformis Phill. Orbiculoidea nitida (Phill.). [Tere- Productus giganteus (Mart.). semireticulatus (Mart.). Rhipidomella michelini (VEveillfr [Orthis auct.] Spirifer bisulcatus J. de C. Sow. duplicicosta Phill. Spirif erina oristata (Sehloth. ). Edmondia (cast). Pleurotomaria sp. Orthooeras sp. Shore \ ml. E. of Linkhead. Grey shale in sandstone overlying the Linkhead Limestone. Telangium affine (L. & H.). [Calym- matotheoa auct.] Sphenopteris machaneki 66pp. subgenioulata Stur. Rhodea patentissima (Ett.). moravica (Ett.). Asterocalamites s,cTdbicv\aXus(8chloth. ). In bay 150 yds. W. of Standalane, barely \ head. Bituminous shale resting on thin coal. Limestone. ml. S.E. of Link- Above the Linkhead Telangium affine (L. & H.). Sphenophyllum tenerrimum Ett. Lepidodendron acuminatum Oopp. Carpolites sulcatus L. & H. Lepidostrobus sp. Sandersdean, 1| mis. S.S.E. of Haddington. Sandersdean Limestone and associated Shale. Batostomella sp. [Chsetetes Monticulipora auct.'] Fenestella plebeia M'Coy. Productus sp. Aviculopecten eskdalensis Hind. and Edmondia oblonga (Portl.). Naiadites crassa (Flem.). Pseudamusium sp. nov. Sedgwickia gigantea M'Coy. Letham Burn, 500 yds. W. of Letham House, l\ mis. W.S.W. of Haddington. Sandersdean Limestone. Aviculopecten intermedius (?) M'Coy. Allorisma sulcata (Flem.). Edmondia rudis (M'Coy). sulcata (Phill.). Myalina pernoides (Portl.). Naiadites crassa (Flem.). Protoschizodus axiniformis (Portl.). Letham Burn, 700 yds. E. of Letham House. The Sandersdean Limestone, first limestone below Letham House. Polyzoa. Spirif erina cristata (ScUoth.). Aviculopecten sp. Naiadites crassa (Flem.). Sanguinolites variabilis (?) M'Coy. Orthooeras sp. PaloBontological. 209 Humbie Water, a few yards above railway bridge, Saltoun Station. The Sandersdean Limestone and Shale. Aviculopeoten sp. Allorisma sulcata (Flem.). Edmondia transversa Hind. Naiadites crassa (Mem,). Euphemus urei (Flem.). [Bellerophon auct.] Letham Burn, 700 yds. E. of Letham House. Second limestone below Letham House. Lepidodendron sp. Lepidophyllum lanceolatum Brong. Sporangia. Spirorbis pusillus (Mart.). Entomostraoa. Elonichthys sp. E. Tyne, opposite the Distillery, Haddington. Lepidodendron veltheimi Sterrib. Lepidostrobus sp. Carpolites sp. Naiadites obesa (S. Eih., [Anthracoptera auct.] Elonichthys sp. jun.). Carboniferous Limestone Series. LOWER LIMESTONE GROUP. Quarry at Lennoxlove, 1 ml. S. of Haddington. Lower Long Craig Limestone (?). Lingula mytiloides J. Sow. Orthotetes crenistria (Phill.). [Strep- torhynchus auct.] Productus semireticulatus (Mart.). Actinopteria persulcata (M'Coy). [Pteronites auct.] Aviculopecten sp. Leptodomus sp. Sanguinolites striatolamellosa de Kon. Solenomya primeva Phill. Bucania decussata (Flem.). [Bellero- phon auct.] Macrochihna sp. Pleurotomaria sp. Orthoceras sp. Shore, Aberlady Point. Middle Long Craig Limestone. Lithostrotion junceum (Flem.). Turbinate corals. Dielasma hastatum (J. de C. Sow.). Productus aculeatus (Mart.). muricatus Phill. punctatus (Mart.). scabriculus (Mart.). semireticulatus (Mart.). Beticularia lineata (Mart.). [Spirifer auct.] " Bhynchonella " pleurodon (Phill.). Seminula ambigua (J. Sow.). [Athyris auct.] Spirifer duplicicosta Phill. Spiriferina cristata (Schloth.). Harelaw Limeworks, Longniddry Station. Upper Long Craig Limestone. Spirorbis sp. Cystodictya parallela (Phill.). [Sulco- retepora auct.] 14 Penestella plebeia M'Coy. _ Pistulipora incrustans (Phill.). Hemitrypa (?) 210 Appendix. Pinnatopora elegantula (R. Eih., jun.). Polypora sp. Rhabdomeson gracile (Phill.). rhombiferum (Phill.). (?) Rhombopora, sp. Chothyris roissyi (IS Eve..). [Athyris auct.] Dielasma hastatum (. Gonatodus punctatus . Elonichthys robisoni ,, striatus . ,, stviatuhis Rhadinichthys ornatissimus ,, brevis . ,, elegantulus ,, formosua Nematoptychius greenooki Wardicnthys oyclosoma Bed o. Bed&. Bedc. X X X X X X X X — X — — * X X — X X — "— X X X • See pp. 59, 84, and 207. t Trans. Roy. Soc, Edin., 1907, vol. xlvi. p. 103. 216 Appendix. Dr. Traquair points out that the assemblage of fishes in the above list is one of Lower Carboniferous estuarine forms, and that not one of the named species can be noted as indicating an Upper Carboniferous horizon. He further adds that eight out of the thirteen species from the beds in " Cheese " Bay also occur in the Wardie Shales — .one of the subdivisions of the Calciferous Sandstone series near Edinburgh, and that of these eight species, four, namely, Gonatodus punctatus, Elonichthys robisoni, Elonichthys. striatus, and Nematoptychius greenochi, are the commonest of all the fishes which are to be found in the Wardie nodules. The following table, again after one by Dr. Traquair, shows the proportion of the specifically determined Gullane fishes represented in Lower Carboniferous estuarine rocks of the Edinburgh district belonging to the Wardie Shales and to higher horizons : — Named Species from Gullane. ■2 m pen to CO . ~ o> o a ■° ° .2 W K s pi .a 2 * p* A Lower Limestone Group. Upper Limestone Group. Bhizodus hibberti Gonatodus punctatus . Elonichthys robisoni . ,, striatus . „ striatulus Rhadinichthys ornatissinms ,, brevis . ,, elegantulus . ,, formosus Nematoptychius greenocki . Wardichthys cyclosoma X X X X X X X X X 2 X X X X X X X X X X X X V V X X — ! X 11 8 5 4 3 4 2 From a consideration of the evidence presented in the second table Dr. Traquair concludes that the fish-fauna of the beds near Gullane shows " the greatest amount of agreement with that of the Wardie Shales of all the horizons in the Lower Carboniferous of Central Scotland in which fishes have been found." Finally he notes that three out of the eleven named Gullane species have not been found in the Wardie Shales nor at any other locality near Edinburgh. Of these three, one is peculiar to the beds in " Cheese " Bay, namely, Rhadinichthys formosus, and the remaining two, Elonichthys striatulus, and Rhadinichthys elegantulus, form part of the peculiar Lower Carboniferous fish-fauna of Glencartholm, on the river Esk, near Canonbie. In addition to the fishes, two schizopods, namely, Tealliocaris loudonensis and T. woodwardi and a phyllopod Leaia leidyi, var. salteriana, were obtained in remarkable preservation from the beds north of Gullane. Tealliocaris woodwardi is mainly confined to the Cementstone group, and is extremely abundant in this subdivision of the Calciferous Sandstone series, especially in the Border territory from Liddisdale to Berwickshire. It occurs in the same group at Dunbar, where it was first found by the late Mr. Bennie, and described by Mr. E. Etheridge, jun.* It is found sparingly in the scorpion bed at Glencartholm on the Esk, near Canonbie — that horizon being above the Fell Sandstones and consequently above the Cementstone group. * Quart. Journ. Qeol. •Sue., vol. xxxiii. p. 863, plate xxvii. Palmontological. 217 Tealliocaris loudonensis, though a new species, is very closely allied to T. etheridgei. The latter form occurs in great abundance in the scorpion bed at Glencartholm, and has also been obtained from the shales associated with the Craigleith Sandstone, and from shales of the Wardie group exposed in the cutting of the suburban railway near Craiglockhart Station. Leaia leidyi, var. salteriana, was named from specimens got low down in the Calciferous Sandstone series at Crail in Fife. The evidence derived from the crustaceans, though indefinite, tends to support Dr. Traquair's conclusion regarding the probable strati- graphical horizon of the fossiliferous bands in " Cheese " Bay, near Gullane. Dr. Kidston states that the plants as a whole indicate the horizon of the Wardie Shales and the scorpion bed at Glencartholm on the Esk, near Canonbie, Dumfriesshire. B. N. Peach. C. VEETICAL DISTRIBUTION OF THE CARBONIFEROUS FOSSILS. Calciferous Sandstone Series. — Organic remains from strata belonging to this series were found at a number of localities, but, as is generally the case in Scotland on this horizon, very few beds represent a normal marine facies of moderate depth. Correlation with the English sequence, on a strictly palseontological basis, is therefore difficult, since the succession established by Dr. A. Vaughan is based on organisms belonging to a normal marine facies. At the same time, those fossils cited in the preceding lists constitute an assemblage which in Scotland is typical of the Calciferous Sandstone series. As shown by Dr. Kidston, the plants are characteristic of the series, and the main facts touching the distribution of the higher Crustacea and Fishes are referred to in the preceding Note. The Lamelli- branchs belong to species chiefly developed in this series, although they can hardly be said to be confined to it. Of the beds containing fossils indicative of a normal marine facies, the Linkhead Limestone is the richest in species, but the state of preserva- tion of the fossils is not satisfactory enough to permit of accurate com- parisons with the forms used as zonal fossils by Dr. Vaughan. However, so far as the present determinations may be trusted, its fauna does not appear to be very different from that of the Lower Limestones, that is, so far as Brachiopod life is concerned, this bed may possibly belong to Dr. Vaughan's D 2 zone. But confirmatory evidence, specially from the Corals, must be obtained before this point can be settled. It is interesting to recall the fact that in the Glasgow district the D 2 zone has its lower limit in strata situated some distance below the Hurlet Limestone, which is taken as the base of the Carboniferous Limestone series (e.g., the Hollybush Limestone, which lies some 40 fathoms below the Hurlet Limestone, contains a typical D 3 assemblage of fossils). Carboniferous Limestone Series. — The fauna of the Lower Limestones belongs to the D 2 phase, which obtains in Central Scotland at the same horizon, the Corals and Brachiopods being essentially D 2 forms, whilst the other classes of fossils represented here also attain their chief develop- ment in beds referred elsewhere to the D 2 zone. Fossils from the Upper Limestones are unfortunately too scantily re- presented to permit of comparisons with the other Upper Limestone districts of Scotland. G. W. Lee. 218 Appendix. II. BIBLIOGRAPHICAL. LIST OF WRITINGS REFERRING TO THE GEOLOGY OF THE AREA INCLUDED IN THE MEMOIR. Compiled by Mr. David Tait. 1805. Jameson, R. A Mineralogical Description of the County of Dumfries. 1811. Ogilby, J. On the Veins that occur in the Newest Floetz-trap Formation of East Lothian. Mem. Wernerian Nat. Hist. Soc, vol. i. p. 469. 1811. Ogilby, J. On the Transition Greenstone of Fassney. Mem. Wernerian Nat. Hist. Soc, vol. i. p. 126. 1818. Macknight, T. Description of Ravensheugh. Mem. Wernerian Nat. Hist. Soc, vol. ii. [1811-1816], p. 404. 1821. Boue, A. Essai Geologique sur l'ficosse [not dated], p. 94. 1821. Jameson, R. Geognosy of East Lothian. Mem. Wernerian Nat. Hist. Soc, vol. iii. p. 225. 1822. Playfair, J. The Works of John Playfair with a Memoir of the Author, 4 vols. [Illustrations of the Huttonian Theory], vol. i. p. 328. 1832. Thompson, R. D. Contributions to the Geology of Berwickshire. Mag. Nat. Hist., vol. v. p. 637. 1835. Milne-Home, D. On the Geology of Berwickshire. Rep. Brit. Assoc [Edinburgh Meeting, 1834], p. 625. 1837. Milne-Home, D. On the Geology of Berwickshire. Trans. Highl. Soc, vol. xi. p. 171. 1838. Cunningham, R. J. H. On the Geology of the Lothians. Mem. Wernerian Nat. Hist. Soc, vol. vii. pp. 3-160 ; and separately 8vo Lond. and Edin. 1839. [With thirty-five coloured sec- tions and a Geological Map of the Lothians.] 1839. Maclaken, C. Geology of Fife and the Lothians. Edin. 1840. Milne [Home], D. Memoir on the Mid-Lothian and East Lothian Coal Fields. Trans. Edin. Roy. Soc, vol. xiv. p. 253; and separately with additions, 1839, Blackwood, Edin. 1842. Buckland, W. On the Evidence of Glaciers in Scotland and the North of England. Geol. Proc, vol. iii. p. 345. 1849. Stevenson, W. On the Geology of Cockburnlaw, and the adjoining District, in Berwickshire ; with a Map and Sections. Trans. Edin. Roy. Soc, vol. xvi. p. 33. 1850. Stevenson, W. On a Gap in the Greywacke Formation of the Eastern Lammermuirs filled by Old Red Sandstone Conglomerate. Quart. Journ. Geol. Soc, vol. vi. p. 418. 1851. Portlock, J. E. Notice of the manner in which Trap or Igneous Rocks intrude into the Sandstone and Conglomerate near North Berwick. Rep. Brit. Assoc, for 1850, p. 101. 1859-1860. Davidson, T. The Carboniferous System in Scotland Characterised by its Brachiopoda, vol. ii. p. 461 ; vol. iii. pp. 14, 99, 179, 219, 235, 258. 1860. Geikie, [Sir] A. Tabular View of the Carboniferous System in the Lothians. The Geologist, vol. iii. p. 239. 1863. Allman, G. J. On a New Fossil Ophiuridan, from Post-Pliocene Strata of the Valley of the Forth. Proc Roy. Soc. Edin., vol. v. p. 101. Bibliographical. 219 1866. Howell, H. H., [Sie] A. Geikie, and J. Young. Memoirs of the Geological Survey of Great Britain. The Geology of East Lothian [one-inch map 33]. 1869. Young, J. Discovery of Archseocidaris Urei in Shale on Dunbar Coast. Proc Glasg. Nat. Hist. Soc, vol. i. p. 94. 1869. Gray, R. Discovery of Ophiolepis gracilis in Brickclay at West Barns, near Dunbar. Proc. Glasg. Nat. Hist. Soc, vol. i. p. 84. 1871. Young, J. W. Analysis of Haematite from Garleton Hills. Account of Proceedings, Trans. Glasg. Geol. Soc, vol. iii. p. 373. 1872. Balfour, J. W. and F. M. On some points in the Geology of the Bast Lothian Coast. Geol. Mag., vol. ix. p. 161. 1873. Richardson, R. On the Volcanic Rocks and Collateral Phenomena of the North Berwick Coast. Trans. Edin. Geol. Soc, vol. ii. p. 177. 1874. Vogelsang, H. Die Krystalliten, fig. 1, Taf. xiii. 8vo, Bonn. 1876. Etheridge, R., Jun. On an Adherent Form of Productus and a small Spiriferina from the Lower Carboniferous Limestone Group of the East of Scotland. Quart. Journ. Geol. Soc, vol. xxxii. p. 454. 1876. Etheridge, R., Jun. On the Occurrence of the Genus Astrocrinites [Austin] in the Scotch Carboniferous Limestone Series, with the Description of a new Species [A, ? Benniei] and Remarks on the Genus. Quart. Journ. Geol. Soc, vol. xxxii. p. 103. 1877. Etheridge, R., Jun. Further Contributions to British Carbon- iferous Palaeontology. Geol. Mag., 2nd Dec. vol. iv. p. 241. 1877. Etheridge, R., Jun. On the Occurrence of a Macrurous Decapod [Anthrapalsemon 1 Woodwardi, sp. nov.] in the Red Sandstone, or lowest group, of the Carboniferous Formation in the South- east of Scotland. Quart. Journ. Geol. Soc, vol. xxxiii. p. 863. 1880. Davidson, T., and A. Somervail. Catalogue of the Brachiopoda of the Lothians and Fife. Prepared by the Society's Lothians and Fife Palseontological Committee. Trans. Edin. Geol. Soc, vol. iii. p. 68. 1880. Geikie, [Sir] A. On the Carboniferous Volcanic Rocks of the Basin of the Firth of Forth — their Structure in the Field and under the Microscope. Trans. Roy. Soc. Edin., vol. xxix. pp. 437-518, plates ix.-xii. 1888. Teall, J. J. H. British Petrography : with .Special Reference to the Igneous Rocks. Lond., pp. 166, 187, 190, 285. 1892. Geikie, [Sir] A. Anniversary Address of the President [History of Volcanic Action in the British Isles from Devonian to Tertiary times]. Quart. Journ. Geol. Soc, vol. xlviii. p. 60. 1892. Hatch, F. H. The Lower Carboniferous Volcanic Rocks of East Lothian [Garlton Hills]. Trans. Roy. Soc. Edin., vol. xxxvii. pt. 1., pp. 115-126, plates i. and ii. 1897. Geikie, [Sir] A. The Ancient Volcanoes of Great Britain, 2 vols., Lond. [Garleton Hills], vol. i. pp. 102, 370, 377-380, etc. 1899. Peach, B. N., and J. Horne. Memoirs of the Geological Survey. The Silurian Rocks of Britain, vol. i. Scotland. 1902. Dron, R. W. The Coal- Fields of Scotland, 8vo, Lond. 1903. Young, B. R. An Analcite Diabase and other Rocks from Gullane. Trans. Edin. Geol. Soc, vol. viii. pp. 326-335. 1903-4. Teall, J. J. H. Summary of Progress of the Geological Survey, for year 1902, pp. 120-129. 1903, pp. 98-108, 113-115, 121-123. 220 Appendix. 1904. Goodchild, J. G. Canty Bay and the Bass. With Special Reference to the Eruptive Rock of that part. Hist. Berwick- shire Nat. Club, vol. xviii. 1901-1902, p. 41. 1904. Goodchild, J. G. Old Cambus, the Siccar Point, and Cove. [Report of Meetings for 1902.] Hist. Berwickshire Nat. Club, vol. xviii. [1901-1902], p. 226. 1905. Bailey, E. B., and D. Tait. On the Occurrence of True Coal- Measures at Port Seton, East Lothian. Trans. Edin. Geol. Soc, vol. viii. p. 351. 1905. Crampton, C. B. The Limestones of Aberlady, Dunbar, and St. Monans. Trans. Edin. Geol. Soc, vol. viii. p. 374. 1905. Teall, J. J. H. Summary of Progress of the Geological Survey. for year 1904, pp. 90-98. 1908. Kendal, P. F., and E. B. Bailey. The Glaciation of East Lothian South of the Garleton Hills. Trans. Roy. Soc. Edin., vol. xlvi. p.l. INDEX Abeblady, 3, 39, 101, 138. Coast section near, 139, 140. Coral Limestone, 143. Raised beaches near, 181, 183. water supply, 203. Acre Limestone, 38. Aoassiz, A., 172. Agriculture, 10, 201. Aikengall Burn, 178. Alderston Mains, 80. Allpoet, 8.. 107, 109. Alluvium, 185. Amisfield Mains, 81. Amygdules, Vertical, 75, 77. Analcite basalts, 3, 99. Petrology of, 105-113. Analcite olivine dolerites, 114—116. Analyses of analcite basalts, 113. basalts, 121. coals, 187, 189, 190, 191, 192. essexite, 117. kulaite, 127. limestones, 52. phonolitic trachytes, 130. trachytes. 133. Partial, of ironstone, 195. Andebson, Dk. T., 65. Arenig Rocks, 2, 12. General description of, 13-19. Ash, Green, 59, 60, 62. General description of, 63-66. Ash Necks, 52. ( ieneral description of, 89—97. Bailey, E. B., 3, 5, 54. Balgone Hill, 180, 1*5. Ballagan Beds, 51. Ballencrieff, 80. Mains. 56. Bangly Braehead Quarry, 80, 131, 199, 200. Bankpark Fireclay Works, 194. Bankton, 159, 196, 202. Colliery, 151. 191. Barness, Coast section near, 134, 135, 137, 138. East Limestone, 134, 138. Baro Quarry, 198. Baeeon, T., 129. Babbow, G., 105, lis. 120, 123, 132. Barytes, 163, 167, 195. Basalt, 3, 69-74, 99, 196, 199. Analyses of, 121. Crajglockhart type of, 118-119. DunBapie type of, 119-120. Markle type of, 120-121. Petrology of, 118-123. Bass Rock, 6, 76, 97, 129, 130. Bathan's Strand, 101, 115. Bauee, M., 107. Beanston, 171. Bearford, 55. Belhaven Bay, Ash Neck at, 90. Map of, 89. — ■ Raised beaches at, 183-184. stained Cementstones, 52. Bennie, J., 206, 216. Berwick Burn, 33. 45. Bibliography, 218-220. Biel, 66, 94, 164. Water, 53, 89. Bilsdean, Section near, 45, 46, 47. Birkhill Rocks, 13, 19-21. Birns Water, 53. Black Law, 174. Black Rocks, 109. Blackie Heugh, 118, 125. Blance Bridge Quarry, 144, 210. Blegbie Quarry, 198. Blinkic Burn section, 17. Blown sand, 8, 184. Bore at Elphingstone Colliery, 149. Gladsmuir, 83, 142. Gosford House, 142. Halls, 29. Kidlaw, 202. Lennoxlove, 54-57. North Berwick, 63, 66, 204. Seacliff, 63, 204. Bore near Catcraip;, 136, 204. Gullane, 84-85, 203. Tranent, 203. Boulder clay, 8, 9. General description of, 181. Beady, H. B., 206. Braidwood Burn, 166, 174. Branxton, 45. Breccias, Old Red, 33. Broad Haven, 53. Brothershiels Burn, 16. Broxburn, 43, 134. Broxmouth, 33, 45, 135. fault, 49, 166. Section near, 49, 136. Volcanic rocks near, 49, 88. Building stone, 195-197. Burnside, 78. Buet, A., 191. Buxley, 151. Calctferous Sandstone Seeies, 2-3, 26, 38, 39, 40, 197. Building stone of, 196. Fossil lists from, 207-209. 221 222 Index. Calciferous Sandstone Series, General de- scription of, 42-88. Note on fossils from, 217. Caldale, 81. Cau,en, T., 198. Canty Bay, 62. Car, 61, 62, 96. Caradoo Eocks, 2, 12. General description of, 13-19. Carbonaceous Group of Northumberland, 38, 40, 45. Carboniferous Fossils, Vertical Distribu- tion of, 217. Carboniferous Limestone, 37, 40, 198. - Edge Coal Group of, 40, 147-154, 188-193, 196. ■ General description of, 134- 156. Lower Limestone Group of, 40, 134-146, 187 ; fossils, 209. Upper Limestone Group of, 40, 154-156 ; fossils, 214. Carboniferous Bocks, Introduction to, 37^11. Carperstane, 67, 78, 79. Castlecary Limestone, 3. Castle Rocks, 91, 100. Catcraig, 50, 135, 136, 137. ■ Bore near, 50, 136, 204. Dykes at, 163. faults, 167. Striae at, 170. Cementstone Group, 2, 34, 40, 43, 47, 51-53. ■ General description of, 58-68. Central Valley of Scotland, Develop- ment of, 9, 10. Channels, High Level, 178. Low Level, 179. Chapel Point Limestone, 134, 137, 198. Cheese Bay, 84. Fossils from, 207. Notes on fossils from, 215-217. Cherts in Carboniferous Rocks, 67, 137. in Old Bed Sandstone, 28, 31, 32. in Silurian, 14, 15, 16, 17, 18. Chesterhall, 165. Chesters Quarry, 79, 100, 109, 110, 198, 199, 203. Chlorite, 63. Clabk, J., 191. Clabke, P., 198. Cleland, J., 49. Clints Quarry, 198. Clotjgh, C. T., 105, 170. Coal-Measures, 41, 193. ■ General description of, 159- 161. Coal seams in Calciferous Sandstone Series, 45, 47, 48, 49, 50, 54, 55, 187. Edge Coal Group, 3, 11, 38, 40, 147-156, 188-193. Lower Limestone Group, 135, 140, 142, 187. Coalstoun, 55, 187. Water, 185. Cockburn, 164. Cockburnlaw granite, 23. Cockburnspath, 40, 42, 43, 204. Cockenzie, 11. Cockham Pit, 151. Cocklaw Hill, 178. Collegehead, 182. Common House, 178. Congalton Mains, 74, 124. Conglomerates, Old Red, 27, 28-30. Copper ores, 195. Cornstones, 30-36, 52. Corroms, 178. Costerton Cottage, 53, 175. Cove Harbour fault, 42, 43. — Limestone, 46, 50. Limestone, Fossils from, 207, 215, 216. - Sandstone, 47. - Section at, 44. Section near, 31. Cowton Rocks, 63, 71, 82. Craigie Hill, 77. Craigielaw Point, 141. Craigleith, 116-118. Craiglockhart type, 119. Craigmillar Sandstone, 171. Craigs Quarrv, 78, 132, 200. Craigy Hill, 132. Ceampton, C. B., 3, 39, 206. Crichton Dean Limestone, 53, 145, 146. Crowhill Coal, 50. Dalskelly CBAfcs. 101, 140. Section at, 141. Danskine Burn section, 28. Davis, W. M., 60. Desert conditions, Supposition of, 32, 60. Deuchrie Dod, 173, 174. Dick, A.. Jun., 113. Dirleton, 78, 79, 85, 109. Dirrington Great Law, 29. felsite, 23. Dodridge Law Quarrv, 145. Dolerite, 5, 101, 162^-164, 193, 199, 200, 201. Dolomitic limestone, 39. Dolphingstone Colliery, 194. Donolly Reservoir, 165. Dove Rock, 89, 91. Drem, 76, 79. Dry Burn, 43, 50, 178. Dun Limestone, 46, 47. Dunbar, 2, 3, 39. 40. 41, 43, 45, 51-53, 163, 170. Glacial deposits near. 10, 176. Raised beaches at, 8. 183. Section at, 52. volcanic necks, 90-95, 105. rocks, 87. water supply, 204. Dunbar-Gifford fault, 2, 25, 33, 37, 53, 94, 166. Dunglass Burn, 43, 45, 47, 49. Dean, 196. Dunsapie type, 119-120. Dykes, East and West dolerite, 5, 23. 24, 150, 162-164, 195, 200, 201. Eahnsclet/oh Burn, 20. East Linton, 68, 70, 72. East Salton Quarry, 140, 143. Fossils from, 211. Easter Broomhouse, 164. Economics, 187-204. Index. 223 Edge Coal Group, 38, 40, 138. Building stones of, 196. General description of, 147- 156. Eel Burn, 83. Eelwell Limestone, 37. Eldbottle Brae, 182. Elphingstone Colliery, 161, 189, 191, 192. Bore at, 149. Englacial streams, 180. Erratics, 169. Large limestone, 54, 146, 171. Essexite, 3. Analyses of, 117. Petrology of, 116-118. Etheridge, R. Jun., 216. Evans, Dr. J. W., 105. Evaporation, Limestones probably pro- duced during, U7. Eweford, 177. " Extra " Limestone, 155. Eyebroughy Scar, 77, 99. Fala, Sandstone near, 28. Dam Burn, 54. Moss, 186. Falconer, Dr. J. D., 108, 162. False-bedding, 47. Faseny Water, 22. Faults, 2, 4, 5, 7, 25, 31, 33, 35, 37, 53, 54, 64, 134, 141, 151, 164, 165-167. Fell Sandstones, 40, 45. Fernylee, 86, 100, 105, 106. Fidra I., 99. Fireclays of economic interest, 193. Five-Feet Coal, 49, 89. Five Yards Limestone, 37. Fleets Colliery, 151, 155, 189. Flett, Dr. J. S., 45, 65, 104, 109, 114, 123, 137, 162. Ford, Section at, 154. Fossil plants, 48, 60, 159, 160. Fountainhall, 195. Four-Feet Coal, 147, 148. Frances Craig, 101. Galalaw Quarry, 200. Galena, 163, 167, 195. Ganister, 137. Garleton Hills, 6. Glaciation of, 170, 178-181. Volcanic Rocks of, 53, 54, 58-88, 94. Garnet, 35. Garvald, 17. Dry valley near, 173. laccolite, 99. Gegan, 62, 99. Geikie, Sir A., 6, 22, 23, 25, 26, 28, 29, 58, 91, 92, 93, 98, 103, 118, 195. Gifiord, 2, 53. Sandstone, 54. Gilbert, G. K., 98. Glacial deposits, 5. — — drainage channels, 7, 173. striie, 170. Glaciation, 168-181. Phases of, 8. Glaciers, Local, 177. Gladsmuir, 4. Bore at, 83, 142. Glenkiln Rocks, 13-19. Goodchild, J. G., 27, 32, 34, 51 , 63, 64, 97. GoBford Bay, 101, 115, 140. Quarry, 200. Gosford House, Bore at, 142. Grabham, G. W., 162. Granite, Cockburn Law, 23. Dirrington Great Law, 23. Priestlaw, 22, 41, 193. Gravel, Coastal Spread of, 176. of the Lammermuir Terrace, 174. Great Seam, 147, 148, 149, 192. Outcrop of, 150-152. Green Ash, 63-66. Gullane, Bore near, 84-85, 203. Raised beach at, 182. Sills at, 101, 114. water supply, 203. Gunn, W., 3, 37, 38, 40, 45, 46, 47, 187. Haddington, Calciferous Sandstone of, 53-57. Trachytes of, 75, 79, 196. trachytic tuff, 80. water supply, 203. Haematite mined, 195. Hailes Castle, 72. Hairy Craig sill, 98, 129. Hall, J., 22. Halls, Bore at, 29. Hardens Hills, 29. Hardraw Scar Limestone, 37. Harelaw Quarry, 142, 209. Harker, A., 74, 114, 122, 123, 127. Hartfell Rocks, 13-19. Hatch, Dr. F. H, 3. 79, 97, 103, 104, 106, 109, 110, 118, 119, 120, 129, 131, 132. Hauchielin Coal, 149, 153, 188. Headshaw Burn, 14. Graptolites from, 15. Headshaw Hill Quarries, 16. Hedderwick Burn, 184. Hibsch, J. E.. 117. Highland erratics in East Lothian, 169. Hind, Dr. W., 38, 160, 206. Hinde, Dr. J. C, 137. Hislop, G. R., 189, 192. History of the landscape, 8. Hope Quarry, 211. Hope's Water, 16, 17. Hoprig, 33, 45. Horne, Dr. J., 2. Hornshill Quarry, 198. Horse Roads Sandstone, 44. 45. Howell, H. H, 26, 53, 73, 98. 154, 161. Hull, Prof. E., 107. Humbie Water, 35, 53, 56, 57. Hummel Rocks, 101. Huntingdon, 79. Hutton, J., 25. Ice Moulding, 170. Ice Sheet, Retreat of, 172-177. Iddings, J. P., 112. Igneous intrusions, 2, 3, 4, 95-101, 104, 105-118, 119, 120, 127, 128-133. in Silurian Rocks, 22-24. later than Coal -Measures, 162— 164. Igneous rocks used as road metal, 198- 201. 224 Index. Index Limestone, 155, 194. Innerwick Castle, Section near, 50. Innerwick fault, 43, 135, 166. Ironstone, Black-Band, 148, 194. Mines, 152. Nodules, 85, 138. Jerusalem, near Haddington, 142, 198. Jones, T. R., 206. Joppa Quarry, 194. Judd, J. W., 107, 120. Kaimes Qxtaery, 199. Kelphope Burn, 13. Graptolites from, 13, 14. Kemp, J. F., 113. Kendall, Proe. P. P., 5, 54, 173, 177. Kidlaw, Bore at, 202. Kidlaw Quarry, Gigantic erratic at, 54, 146, 172. Fossils from, 212. Sill at, 100, 106, 199. Kidlaw type, 91, 106, 111-114. Kidston, Dr. R., 3, 41, 68, 157, 206, 217. Kilduff Hill, 79. Kilspindie, 141. Kingston, 78. HDL 74. Kip Carle Sandstone, 45, 46. Kippie Law, 119. Kirkby, J. W., 38, 206. Knockenhair, Intrusion at, 91, 1 100, 106. Knock Hill, 30. Kulaite, 73. Analyses of, 126. Petrology of, 125. Laocolites, 95-101. Lacroix, A., 109-117. Lairds Quarry, 85. Lamb I., 99, 108. Lammer Law, 6, 7, 8, 13, 16, 17, 177. Graptolites from, 16, 17. Lammerlaw Burn, 14. Graptolites from, 14. Lammermuirs, 2, 4, 7, 8, 12, 29, 30. Fault, 2, 4, 5, 27, 165. Glacial Phenomena, 168, 173. Terrace, 174. Lampland Quarry, 198. Section at, 144. Landridge, 142. Lapworth, C, 12, 13. Lauderdale, 10. Lawhead Hill, 68, 74. Law Quarry section, 144. Lee, Dr. G. W., 20ii. Lennoxlove, Bore at, 54, 55, 57. Limestone, 5, 55, 146. Fossils, 209. Lenny Quarry, 199. Letham Burn, 56. Fossils, 208. Levy, M., 120, 131. Lickar Coals, 38. Limestone Quarries, < leneral account of, 197-198. Limplum, 100, 106. Limylands Colliery, 189. Linkhead Coal, 49, 187. — Limestone, 48, 50. fossils, 208, 217. Links House, 83. Linn Dean Water, 177. Little Pinkerton, 43. Llandeilo Bocks, 2, 12, 13-19. Llandovery Rocks, 2, 12, 13. Long Craig Limestone, Lower, 37, 39, 50, 136 ; fossils, 209. Middle, 134, 136, 143, 144, 145, 197 ; fossils, 209. Upper, 39, 136, 143, 144, 145, 197, 198 ; fossils, 209. Longformacus, 4, 12. Longniddry Quarry section, 56, 142. Long Yester, 203. Macconochie, A., 35, 36, 55, 56, 60, 61, 62, 67, 68, 84, 87, 108, 136, 206, 215. M'Gee, W. J., 60. Mackinder, H. J., 9. Macklaren, C, 26. Macmerry, 149, 152, 189. Mammalian bones in old lake deposit, 185. Marginal channels, 179. footing, 179. Markle Quarry, 118, 120-123. Marl in Old Red Sandstone, 30-36. Law Quarry, 172. Maufe, H. B., 5, 9, 27, 170. Mill Burn, 30, 75. Miller, Hugh, 40. Millstone Grit, 3, 41, 151, 194. General description of, 157- 159. Millstone Neuk Quarry, 163, 200. Milne Home, D., 160, 193. Moffat Series, 2, 4, 12-19. Wood, 142. Monchiquite, 3, 99. Petrology of, 11, 105-113. Montfair Pit, 152, 189. Mugearite, 70, 72, 74-75, 97. Analyses of, 126. Petrology of, 123-124. Mtttr, J., 215. Mxjrohison, Sir R. I., 185. Mussel-band, 55, 56. Muttonhole Quarries, 145. Nairns Mains, 142. Necks, Volcanic, 35. General description of, 89, 95. Nepheline x, 110. Nether Hailes, 80. Newhall Burn, 54. Niddrie, 155. Nimmo, J., 189. North Berwick, 39, 58, 62, 65, 66, 68, 70, 184, 196. Bore in, 63, 66, 204. Faults near, 167. Map of, 59. water supply, 203. North Berwick Law, 6, 62, 69, 76, 130, 197. Trachytic Stock at, 97. Northfield Colliery, 150. Index. ■225 Oatleyclettoh, 23. Ogle Burn, 166. Oil-shale, 40, 47, 56, 57, 67, 83. Oldhamstocks, 40, 86, 195, 204. Burn, 33, 44, 45, 86. fault, 166. glacial deposits, 172, 176. Olivine nodules, 107. Ormiston, 153. Coal, 191. Ostracods, 62, 67. Oxenford Mains, 154. Oxford Limestone, 47. Oxwell Mains Quarry, 137. Fossils from, 213. Pal^obotanical Break in Millstone Grit, 41, 141. Palaeontological Appendix, 206-217. Panwood Coal, 150, 152, 190, 194. Papana Water, 17, 18, 35, 165. Graptolites from, 18. Parrot Coal of Ford, 154. Tranent, 147, 148, 149, 191. Partan Craig, 68. Pathhead Quarry, 138, 153, 198. Peach, Dr. B. N., 2, 10, 27. 29, 91, 206. Pease Mill, 32. Peaston Quarry, 144. Peat. 186. Peffer Burn, 171. Peneaitland, 175. Pencraig laoeolite, 99. Quarry, 76, 200. Wood, 179. Penston Coal, 148, 149, 152, 189. Ironstone, 194. Peppercraig Quarry, 79, 197, 199. Petrographical province, 133. Petrology of analcite basalts and mon- chiquites, 105-113. basalts, 118-123. Craigleith essexite, 116-118. teschenites, 114-116. trachydolerites, 123-127. trachytes, 127-133. Phillips, J. A., 37. Phonolite, 6. Phonolitic trachyte, 128-130. Physical features, 5-8. Pirsson, L. V., 104. Player, J. H., 103. Playfair, J., 22, 25. Pleistocene deposits, 1S5. Point Garry, 66, 101, 115. Pollard, Dr. W., 104, 126. Population, Distribution of, 10. Porphyritic trachyte, ] 32. Port Seton, 4, 10, 41. 152, 154, 192. Dyke at, 163. fossils, 214. Section at, 157-159. Pressmennan Loch, 100, 173. Prestongrango Colliery, 192. Preston Links Colliery, 11, 150, 18N, 190. 192, 193. Prestonpans, 4, 37, 41, 162. water supply, 202. Priestlaw granite, 4, 22, 195. Petrology of, 22. IS Prior, Dr. G. T„ 110. Pyroclastic rocks between lavas, 80- 83. Quartz, Secondary, 35. banakite, 79. Analyses of, 133. Petrology of, 131. trachytes, 132. Queensberry Grits, 20. Radley, B. G, 104. Raised beaches, 181-184. Fossils from, 215. Rammer Cleugh, 174. Ramsay, Sir A., 26, 27. Ratho Quarry, 199. Ravelrig Quarry, 199. Recent deposits, 185. Fossils from, 214. Red Scar, 175. Rentonhall, 55, 196. Rhodes Quarry, 66, 67, 197. Rigganhead, 152. Road metal, 198-201. Rockville House, 124. Rosenbusch, H., 113, 129. Roslin Sandstone. See " Millstone Grit." Rough Coal, 148, 149, 189. Rucklaw, 68. Rutile, 35. St. Baldred's Cradle, 60. 61, 95, 100, 119. St. Monans section, 3. 39. Salton quarries, Section at, 143, 198. Samuelston, Section at, 142. Sand, 197. Blown, 181. Sandersdean, 55, 56. Limestone, 56, 57. Fossils, 208, 209. Sauchet Water, 19, 35. Saughland, 53. Scoughall, 61. Scremerston group of Northumberland, 38, 40, 45, 54. Seacliff House, 63, 67. Igneous rock at, 96. Bore at, 63, 204. Sediment, Inclusions of, in lavas, 79-81. Sedimentary dykes, 101-102. Seton West Mains. 200. Seymour, H. J., 129. " Sheetfloods," 61, 81. Siccar Point, 26, 27, 31. Coast section at, 31. Sills, Intrusive, 99-101, 162, 198, 199, 200, 201. Petrology of, 103-133. Silurian Rocks, 2, 12-21, 198. Filled valleys in, 2, 25, 36. Igneous intrusions in, 22-24. Reduplication of, 4, 12, 20. Silver Hill Quarry, 79. Skateraw Limestone, Lower, 38, 39, 136 ; fossils, 210. Middle, 137, 145, 197, 198; fossils, 211. Upper, 39, 137, 145; fossils, 211. 226 Index. Skid Hill Quarry, 77, 131, 200. Soonhope Burn section, 20. Sorby, H. C, 32. Southern Uplands, 12. Erratics from, 169. SoutraHill, 16, 198. Glaciation near, 177. Spilmersford, 198. Spittal, 82. Splint Coal of Penston, 189. Tranent, 149, 191. Spott, 25. Staining of limestones, 51-52. Standalane Sandstone, 47, 48. Stenton, 19, 35, 106. Stevenson, W., 26. Sting Bank Burn, 177. Stocks, 95-100. Sunnyside, 68. Limestone, 197. Tait, D., 3, 206, 218. Tantallon Castle, 62. Tarannon Rocks, 2, 4, 12. General description of, 19-21. Teall, Dr. J. J. H., 22, 107, 115. Teschenite, 3, 100-101. Petrology of, 114-116. Thomas, H. H., 82, 167. Thornton Burn, 50, 183. Thorntonloch, 40, 41, 43, 50, 170. Coast section near, 135. Thorter Burn section, 19. Fossils from, 19. Three-Feet Coal, 147, 148, 149, 150, 153, 190, 191. Tourmaline, 35. Trachydolerite, 74-75. Petrology of, 123-127. Trachyte, 3, 75-79, 97-99. Analyses of, 130, 133. Petrology of, 127-133. Tranent, Possible water supply for, 203. Tranent Collieries, 149, 151, 190, 192, 196. Traprain Law, 6, 51, 53, 66, 70, 73, 128. laccolite, 98, 200. Traquaik, Dr. B. H., 3, 35, 52, 157, 215, 216. Tuff, 35. trachytic, 80. Turgite, 34. Tyne, R., 143, 185. Tyne Mouth, 60, 6195, 181, 183. Tyneside Pit, 189. Unconformity at base of Old Red Sand- stone, 25, 28, 29. in Old Red Sandstone, 29. Under Diamond Coal, 149. Upper Keith, Glacial deposits near, 175. Volcanic rocks near, 88. Upper Limestone Group, 3, 154-156. Vaughan, Dr. A., 217. Vaults, 138. Volcanic Rocks, 2, 3, 58, 59, 61-66, 69-79, 86-88, 103-105, 118-128. Waldie, T., 190. Wallyford, 150. Washington, H. S., 125. Water supply, 202-204. Watts. Prof. W. W., 60. Weak Law, 76, 82, 83. Westcraig Quarry, 199. Wester Broomhouse, 195. West Fenton Quarry, 200. West Fortune, 124. West Peaston Quarry, 198. Whalley, E. B., 169, 176. Whelplaw Burn, 20. Whim Park Quarry, 85. Whiteadder, River, 22. Whitekirk, 71. White Sands, 134, 195. White trap, 163. Whittinghame, 2, 35, 66. Wilson, J. S. G., 52, 102. Windycleuch Burn, 15. Graptolites from, 15. Winton Castle, 196. Woodcote Park, 172. Woodend, 55. Woodend Limestone, 46, 47, 50, 55. Yellow Craig, 100, 101. Yoredale Limestones, 38. Young, Prof. B. R., 5, 104, 108, 114, 170, 180. Prof. J., 185. J. W., 195. Zircon, 35. Zirkel, F., 109. DESCRIPTION OF PLATES. PLATE X. Fig. 1. Slide No. 11,898. Magnified 20 dia. Ordinary Light. Olivine nodule in analcite basalt, The Lamb. The minerals are olivine, diopside, and spinel, and the corrosion borders, especially round the latter, are well shown (p. 108). Fig. 2. Slide No. 11,843a. Magnified 60 dia. Ordinary Light. Augite " spherulite " in analcite basalt, Sherifiside Quarry, east of Gifford. In this instance the base seems to be in part glassy (p. 109). Fig. 3. Slide No. 836b. Magnified 16 dia. Ordinary Light. iEgirine augite showing magmatic absorption, in trachytic phonolite, Traprain Law (p. 127). Fig. 4. Slide No. 1005b. Magnified 16 dia. Ordinary Light. Complex phenocryst of purple-blown augite and olivine in micrographic intergrowth, in monchiquite or nepheline basalt, Chesters Quarry, Whitelaw Hill (p. 109). Fig. 5. Slide No. 11,899b. Magnified 25 dia. Ordinary Light. Olivine nodule with purple-brown augite and olivine in micrographic intergrowth, in analcite basalt, Fidra (p. 109). Geology of East ~ Zorfucw. Plate X, Fi£. 2 Kg.l i^^Jfe** rig. *. Bg.5. HutK, coll PhTVKiMICRO GRAPHS. PLATE XI. Fig. 1. Slide No. 11,738. Magnified 60 dia. Ordinary Light. Interior of analcite crystal, Kidlaw, showing want of zonal arrange- ment of inclusions, mostly augite, magnetite, and olivine. The wonderfully fresh condition of the olivine should be noticed (p. 111). Fig. 2. Slide No. 11,897. Magnified 20 dia. Ordinary Light. Essexite, Craigleith. Olivine quite fresh, augite conspicuous (p. 116). Fig. 3. Slide No. 11,839. Magnified 30 dia. Ordinary Light. Augite teschenite, Gullane. Olivine serpentinised and vermicular serpentine invading area occupied by analcite. See discussion (p. 114). Fig. 4. Slide No. 10,793. Magnified 15 dia. Ordinary Light. Well- formed flakes of biotite in an analcite-filled vesicle in olivine dolerite, Bathan's Strand, south of Frances Craig (p. 115). Fig. 5. Slide No. 10,835. Magnified 12 dia. Ordinary Light. Basalt of Craiglockhart type, Redside. Phenocrysts are augite and olivine (p. 118). Fig. 6. Slide No. 11,308. Magnified 10 dia. Ordinary Light. Basalt of Dunsapie type from the Tyne, south-west of East Linton. Phenocrysts of augite, olivine, and basic labradorite, or bytownite (p. 119). GeoLo \gy of East Lotkuxro Plate M. Hg. 6. Photomk PLATE XII. Fig. 1. Slide No. 11,328. Magnified 20 dia. Ordinary Light, Kulaite, scar below Blaikie Hengh, Balfour Monument, south of Traprain Law. Phenocrysts preponderantly hornblende showing marked resorption. No felspar phenocrysts (p. 125). Fig. 2. Slide No. 629. Magnified 10 dia. Ordinary Light. Basalt of Markle type, Markle Quarry. Phenocrysts of labradorite and olivine (p. 120). Fig. 3. Slide No. 625." Magnified 12 dia. Crossed Nicols. Quartz banakite, Bangly Quarry. Phenocrysts of andesine, etc. (rimmed with sanidine), and eegirine augite in a groundmass of sanidine laths with subsidiary quartz (p. 131). Fig. 4. Slide No. 11,301. Magnified 20 dia. Ordinary Light. Mugear- ite, Railway Cutting, East Linton. The dark pseudo- morphs are after olivine. The felspar laths are mostly oligoclase (p. 123). Fig. 5. Slide No. 10,829. Magnified 32 dia. Ordinary Light. Mugearite, West Fortune. The brown ophitic mineral against the oligoclase phenocryst and in the groundmass is the horn- blende determined by Dr. Flett in the mugearites of Skye and the Lothians (p. 124). Geology of E asb Lotfdaru Plate JUL Fig 1 Fig-4;. Fig. 5. -TFTOT-QMICKO GRAPHS List of Publications of the Geological Survey of Scotland — continued. 85. Elginshire, Banffshire, Aberdeenshire (parts of). 20s. 9d. 87. North-East Aberdeenshire and Banffshire (detached portions). 13s. 3d. 91, Ross-shire (part of), 15s. 6d. , 94. Ross-shire, Cromartyshire, Sutherlandshire (parts of). 8s. 9d. 95. Elginshire, Banffshire (parts of). 5s. 3d. 96. Aberdeenshire, Banffshire (parts of). 7s. 3d. 97. Aberdeenshire and Eastern Banffshire (parts of). 4s. (id. 100. N.W. Ross-shire (part of). 2s. 6d. 101. Ross-shire, Cromartyshire, and Sutherlandshire (parts of). 14s. 103. Sutherlandshire, E. 8s. 9d. 107. Sutherlandshire (part of). 25s. 3d. 113. Sutherlandshire, N.W. (part'of). 5s. 3d. 114. Sutherlandshire (part of N.). 13s. 3d. 115. Sutherlandshire, Caithness-shire (parts of). 19s. 3d. Maps on Six-inch Scale, illustrating the Coal-fields. Edinburghshire. Haddingtonshire. Fifeshire. Ayrshire. Sheets 1, S.W. (and 1b, S.E.), S.E. ; 3, N.W., N.E., S.W., S.E. ; 4, N.W., N.E., S.W., S.E. ; 4a., S.W.; 5, N.E., S.E. ; 7, N.E., S.E. ; 8, N.W., N.E., S.W., S.E. ; 9 (and Haddington 14), N.W., S.W., S.E. ; 11, N.W., S.W. ; 12, S.E. ; 13, N.W., N.E., S.W., S.E. ; 14, N.W., N.E., S.W., S.E. ; 15, N.W. (and Haddington 18, N.W.) ; 18, N.E. ; 19, N.W.,' N.E. (revised editions). Is. Sd. (uneoloured). Sheets 4, S.W., S.E. ; 9, N.W., N.E., S.W., S.E. 14, N.W., N.E., S.W., S.E. editions). Is. 6d. (uneoloured). Sheets 24, 6s. 3d. ; 25, 4s. 3d. ; 30, 5s. ; 33, 2s. ; 35, 7s. ; 36, lis. Sheets 7, 12, 13, 17, 19, 22, 23, 24, 28, 30, 36, 42, 46, 52, 8s. 3d. ; 8, 40, 8s. ; 9, 4s. 3d. ; 11, 18, 29, 34, 18, N.W. (revised 31, 8s. 3d. ; 32, 37, ; 14, (un- 8,23, 41, 9s. 9d. ; 16, 6s. 3d. ; 26, 27, 31, 5s. 9d. ; 33, 35, lis. ; 47, 7s. 9d. ; 50, 10s. 3d. Sheets 7, 11, 9s. 9d. ; 8 and 9, 13, 5s. ; 12, 8s. 3d. 3s. ; 15, 16, 7s. ; 17, 3s. 9d. (old editions). Sheets 12, N.E., S.E. (revised editions). Is. 6d, coloured). Sheets 1, 2, 3s. 3d. ; 3, 3s. Sd. ; 4, 2s. 9d. ; 5, 2s. 3d. 24, 7s. ; 7, 11, 17,' 20, 31, 38, 41, 42, 8s. 3d. 25, 32, 7s. 9d. ; 9, 19, 6s. 3d. j 12, 13, 16, 5s. 10, 5s. ; 18, 37, 9s. ; 49, 4s. 3d. (old editions). Sheets 1, S.E. ; 2, S.E. ; 6, N.E., S.W., S.E. ; 10, N.W (revised editions). Is. 6d. (uneoloured). Sheets 1, 3s. ; 5, 7, 5s. 9d. ; 6, 8s. 3d. Sheets 19a, 20, 24, 2s. 3d. ; 23, 7s. 9d. ; 25, 6s. 3d. 26, 3s. 3d. ; 28, including 29, 3s. Sheets 17, 28, 8s. 3d. ; 18, 31, 4s. 3d. ; 23, 27, 9s. ; 5s. 9d. ; 25, 2s. 9d. ; 29, 7s. ; 30, 32, 5s. ; 33, 2s. 3d. ; 35, including 34, 6s. 3d. (old editions). Sheets 27, S.E. ; 28, S.W. (revised editions). Is. (uneoloured). Sheet 8, 5s. 9d. (old edition). Sheets 1, N.E., S.E. ; 2, S.W. and N.W. S.W. ; 6, N.W., N.E., S.W., S.E. ; 7, S.W. ; 9, N.E., S.E. ; 10, N.W., S.W. (revised editions). Is. 6d. (uneoloured). Sheets 133, 9s. 9d. ; 134, 140, 8s. 3d. ; 135, 5s. ; 139, 142 3s. ; 141, 2s. 9d. ; 143, 2s. Maps on Six-inch Scale, illustrating Structure of N.W. Highlands Sutherlandshire. Sheets 5, lis. ; 71, 20s. 3d. Skye Sheets 38, 20s. ; 39, 16s. ; 44, 22s. 9d. ; 45, 24s. Maps on the Scale of Four Miles to One Inch. Sheet 16. Galloway and part of Ayrshire, &c. ,, 17. Roxburghshire, Dumfriesshire, &c. Printed in Colours. 2s. 6d. each. Horizontal Sections. Sheet 1. Edinburghshire and Haddingtonshire. 3s. 9d. 2. Edinburghshire, Haddingtonshire, Berwickshire. 4s. 3d. 3. Peeblesshire, Edinburghshire, Linlithgowshire. 4s. 3d. 4. Ayrshire Coal-fields (west side). 4s. 3d. 5. Ayrshire Coal-fields (east side). 5s. 9d. 6. Renfrewshire, Dumbartonshire, Ayrshire. 5s. 9d. Renfrewshire. Lanarkshire. Dumfriesshire. Dumbartonshire. Stirlingshire. Linlithgowshire. Perthshire. 24, 36, 6d. , S.E. ; 3, N.W. and ; 12, N.E. List of Publications of the Geological' Survey of Scotland — continued. Sheet 7. Cheviot and Lammermoor Hills. 5s. „ 8. Clyde Coal-field and Campsie Hills. 5s. „ 9. Ayrshire Coal-fields (Muirkirk and New Cumnock. 5s. 9 d. Vertical Sections. Is. 8d. per Shed. Sheet 1. Edinburgh and Haddington Coal-fields. 1a. Midlothian Coal Basin (middle portion). 1b. ,, ,, ,, (western side). IB. „ „ „ (eastern „ ). - 1b. East Lothian Coal Basin. 2. Fife Coal-fields. 2a. Fife Coal-fields. 3. Kilmarnock Coal-field. 4. Clyde Basin Coal-field. 5. Stirling and Clackmannan Coal-fields. . 6. Muirkirk, Lesmahagow, and Douglas Coal-fields. 7. Lanarkshire Coal-fields (Rutherglen and Carluke). Memoirs of the Geological Survey of Scotland. (1.) General Memoir: — Silurian Rocks of Britain. Vol. I. Scotland. 15s. (2.) Economic Memoir: — The Oil-Shales of the Lothians. 4s. (3.) Museum Guide:— Guide to the Collections of the Geological Survey. . 2d. (4.) District Memoirs'. — Cowal, Argyllshire. 6s. East Lothian. 4s. 6d. Central and Western Fife and Kinross. 5s. 6d. Eastern Fife. 8s. Skye. The Tertiary Igneous Bocks of. 9s. Islay, &c. 2s. 6d. The Geological Structure of the North-West Highlands of Scotland. 10s. 6d. Palaeontology. The Higher Crustacea of the Carboniferous Rocks of Scotland. 4s. (5.) Sheet Memoirs : — Sheet 1. Wigtownshire, South-Western Districts. 3a!. „ 2. Wigtownshire, South-Eastern Districts. 3d. ,, 3. Wigtownshire, Western Districts. Sd. ,, 4. Wigtownshire, E. part; Kirkcudbrightshire; portion of S.W. Division. 9d. ,, 5. Kirkcudbrightshire, Southern Districts. Is. 6d. ,, .7. Ayrshire, South-Western District. Sd. ,, 9. Kirkcudbrightshire, N.E. ; Dumfriesshire, S.W. Is. ,, 13. Ayrshire, Turnberry Point. Sd. ,, 14. Ayrshire, Southern District. Sd. ,, 15. Dumfriesshire, N.W. ; Ayrshire, S.E. ; and Lanarkshire, S. Sd. ,, 21. Buteshire (Arran, Central, and N. and S. Bute), Argyllshire, Ayrshire (parts of). 4s. ,, 22. Ayrshire, Northern District, and parts of Renfrewshire and Lanark- shire. 3d. ,, 23. Lanarkshire, Central Districts. Is. ,, 24. Peeblesshire, Lanarkshire, Edinburghshire, Selkirkshire' (parts of). 3d. ,, 31. Lanarkshire, N. ; Stirlingshire, S. ; Linlithgowshire, W. 2s. 3d. ,, 32. Edinburghshire and Linlithgowshire. Out of print. New edition in preparation. ,, 34. Eastern Berwickshire. 2s. „ 36. Seaboard of Mid Argyll. 2s. 3d. „ 37. Mid Argyll. 3s. ,, 45. Argyllshire, The Country near Oban and Dalmally. 2s. 6J. ,, 55. Porthshire, Thfi Country round Blair-Atholl, Pitlochry, and Aberfeldy. 3s. „ 60. The Small Isles of Inverness-shire. 4s. 6d. ,, 70. Inverness-shire. West-Central Skye, with Soay. Is. ,, 75. Inverness-shire, Elginshire, Banffshire, Aberdeenshire (parts of). Is. Sd. ,, 76. Aberdeenshire, Central. Is. 85. Elginshire, Banffshire, Aberdeenshire (parts of). Is. dd. " 87. Aberdeenshire and Banffshire (parts of). 9d. ,', 97. Northern Aberdeenshire. Eastern Banffshire, id. A detailed Catalogue may be had cm application to Messrs. W. & A. K. Johnston, Ltd. 2 St. Andrew Square, Edinburgh. 4 ^V ' V , . ' t f ^ 'XV * «V y* - * A,^ +y ♦ ..V" - ...r-T. '¥!„•*& % at- "•, -ft.