.dl Cornell mttptJiSitg pibatg BOUGHT WITH THE INCOME FROM THE SAGE ENDOWMENT FUND THE GIFT OF Hetirg W. Sage 1S91 ;^.Sf>fr^t)fe ^pnofe. ryr- „^« . Cornell University Library QE 262.A77F79 1900 '■'''e geology of the country between Ather 3 1924 004 550 236 1S5. MEMOIRS OF THE GEOLOGICAL SURVEY. ENGLAND AND WALES. THE GEOLOGY OF THE COUNTEY BETWEEN ATHERSTONE AND CHARNWOOD FOREST. (Explanation of Sheet 155.) BY C. FOX-STRANGWAYS, F.G.S. WITH Notes on Chabnwood Forest by Prof. W. W. Watts, M.A., F.G.S. PDBLISHBD BY OKDBK OF THE LORDS COMMISSIONEKS OF HER MAJESTY'S TREASURY. LONDON: PlilNTED JTOR HER MAJESTY'S STATIONERY OFFICE, BY WYMAN AND SONS, LIMITED, FETTER LANE, E.G. And to be parchased, either dii'ectly or through any Bookseller, from EYRE & SPOTTISWOODE, East Hawjing Stbbbt, Flbbt Strkst, E.G. ; or JOHN MENZIES & Go., Rosb Stkebt, Sdinburoh, and 90, West Nile Street, Glascow ; or HODGES, FIGGIS, & Co., Limited, 104, Geaftoi? Stkbbt, D0BL121. 1900. Price Two Shillingn. fAoH- w;^ LIST OF MAPSi SECTIONS, AND OTHER PUBLICATIONS OF THE GEOLOGICAL SURVEY OF ENGLAND AND WALES. Thb Maps are those ol the Ordnanee Survey, geologically eoloured hy the Geological Survey of the TTnited Kingdom, under the Superintendence of Sir AkoB. GbiBie, D.C.I/., LL.D., F.E.S., Director eeheral. (For Maps, details of Sections, and Memoirs issued by the Geological Survey, see " Catalogue.") ENGLAND AND WALES.— (Scale 1 inch to a mile.) Maps marked ^ are also published as Drift Maps, ^hose marked f are published only as Drift Maps. Sheets 3% 5, 6«, 7», 8*, 9, H to 22, 25, 26, 30, 31, 33 to 37, 40, 41, 44, 47*, 64* 65t, 69t, 70* 83*, 86* price 8s. 6d. each. Sheet 4, 6s. Sheets 2*, 23, 24, 27 to 29, 32, 38, 39, 68, 84t, 86t, 4«. each. Sheets divided into quarters ; all at 3s. eacli quarter-sheet, excepting those in brackets, which are Is. Gd. each. 1*, 42, 43, 45, 46, NW, SW, NE* SE«, 48, NWt, SW*, NEt, (SE*), (49t), 50t, 51* 52 to 57, (57 NW), 59 to 63, 66 SWt, NEt, NW*, SEt, 67 Nt, (St), 68 Et, (NWt), SWt, 71 to 75, 76 (S), S, (77 N), 78, k, NW*j SW, NB*, SE* 80 JTW*, SW* NE*, SE* 81 NW*, SW, NB, SE, 82, 83* 87, 88; *fW, SW* NB, SB, 89 JSVf, SW* NB, SB*, 90 (NE*), (SB*), 91, (NW*), (SW*), KB*, SB* 92 NW* SW*, HE, SB, 93 NW, SW, HE*, SB* 94 NWt, SWt, (NEt), SBt, 95 NW» NE*, (SE*), 96 NW* SW*, NE* SB* 97 NW*, SW*, NE», SB, 98 NW, SW, NE* SB, 99 (NB*), (SB*), 100*, 101 SB, NE* NW* SW*, 102 NW* NE*, •8W*, SB*, 103*, 104*, 105 NW*, SW* (NE*), SB*, 106 NW*, SW* NE*, SB* 107 SWt, NE», SE* 108 SW* NE*, SB*, 109 NW*, SW*, SB*, 110 (NW*), (NE*), SE*, SW*. JVeW Series.— I. of Man*, 36, 45. 46, S6, 67; Bs. id. I. of Wight, with MaiulaM*, 330, 331, 344, 345, 8s. 6d. 155*, 203t, 231*, ' 232*, 248*, 249*, 263*, 267t, 268* 282t, 283t, Z84t, 299t, 300t, 316t, 316t, 326t, 323t, 329*, 339t, 330* 381* (332*), (333*), 334* 339t, (340t), (341t), 342t, 343t, 349t, 350t, 366t, (366t). Price 3s. each, excepting those in brackets which are Is. ed. each. GENERAL SIAP :— (Scale 4 mUes to 1 inch.) ENGLAND AND WALES;— Sheet 1 (Title) ; 2 (Northumberlandi &c.) ; 3 (Index of Colours) ; i (I. of Mai) ; 5 (Lake District); 6 (E. Yorkshire) ; 7 (N. Wales) ; 8 (Central England) ; 9 (Eastern Counties) ; 10 (S. Wales and N. Devon) ; 11 (W. of England and S.B. Wales) ; 12 (London Basin and Weald) ; 13 (Cornwall, &c.) ; 14 (S. Coast, Torquay to I. of Wight) ; j 15 (S. Coast, Havant to Hastings). JV«w Series, printed in coloiws, sheet 1, 2s. ; sheets 2 to 16, 2«. 6d. eaoh. , HOBIZONTAL SECTIONS. 1 to 140, 146 to 148, England, price 6s. each. VERTICAL SECTIONS. 1 to S2, England, price 3s. 6iJ. each. COMPLETED COUNTIES OF ENGLAND AND WALES, on'a Scale of 1 inch to a mile. Old Series. Sheets marked * have Descriptive Memoirs. ANSLBSByt,- 77 N, 78. BBDBOB.DSHIEE,— 46 NW, NE, SWt, SEt, 52 NW, NE, aw, SB. BEKKSHIEE,— 7*, 8t, 12*, 13*, 34* 45 SW*. BRBeKNOCKSHIRBt,— 36, 41, 42, 56 NW, SW, 57 NE, SE. BUCKINGHAMSHIRE,- 7*, 13*, 45* NB, SB, 46 NW, SWt, 52 SW. CABRMARTHBNSHIREt,— 37, 38, 40, 41, 42 NW, SW, 56 SW, 67 SW, SE. CABUNARVONSHIREt,— 74 NW, 75, 76, 77 N, 78, 79 NW, SW. CAMBRIDGBSHIREt,— 46 NE, 47*, 61* 62 SE, 64*. CARDIGANSHIEBt,— 40, 41, 66 NW, 67, 68, 69 SE, 60 SW. OHESHIRB,— 73 NB, NW, 79 NB, SB, 80, 81 NW*, SW*, 88 SW. f'OSNWALLt,— 24t, 26t, 26t, 29t, 30t, 31t, 32t, & 38t. CUMBERLAND,— 98 NW, SW* 99, 101, 102, NE, NW, SW*, 106 SB, SW, NW, 107. , ^ „ DENBIGHt,— 73 NW, 74, 75 NB, 78 NB, SE, 79 NW, SW, SB, 80 SW. DBRBVSHIBEt,— 62 NB, 63 NW, 71 NW, SW, SB, 72 NE, 72 SB, 81, 82, 88 SW, SB. • » DBVONSHIRBt,— 20t, 21t, 22t, 23t, 24t, 26t, 26t, & 27t. DORSETSHIRE,— 15, 16, 17, ISS, 21, 22. DURHAM,— 102 NB, SB, 103, 105 NB, SE, SW, 106 SB. ESSEX,- 1>, 2*, 47*, 48*. jrMNTSHIRBt,^74 NE, 79. GLAMOKGANSHIREt,— 20, 38, 37, 41, & 42 SE, SW. ,44*. Sheets or Counties marked t are illustrated by General Memoirs. 64*, 70*, 71 SE, GLOUOESTBRSHIRBt,— 19, 34*, 36, 43, NE, SW, HAMPSHIRE,- 8t, 9t, 10* lit, 12», 14, 15, 16. HBRBrORDSHIRB,— 42 NB, SB, 43, 55, 56 NB, SE. HERTFORDSHIRB,— It NW, 7*, 46, 47*. HUNTINGDON,— 51 NW, 62 NW, NE, SW, 64* 65. KENTt,— It SW & SE, 2t, 3t, i\ 6*. LANCA3HIRB,-79 NB, 80 NW*, NB, 81 NW, 88 NW, SWt, 89 no 91i92SW,9g. See also Xeio Series Maps. LEICESTERSHIRE,- 53 NE, 62 NE, SW. LINCOLNSHIRBt,— 64* 66* 69, 70*, 83*, 84*, 85*, 86*. MBBIONETHSHIREt,— 59 NE, SE, 60 NW, 74, 76 NB, MiDDLBSBXt,— It NW, SW, 7*, 8t. MONMOUTHSHIRE,— 35, 36, 42 SB, NE, 43 SW. MONTGOMBRYSHIREt,— 56 NW, 69 NE, SB, 60, 74 SW SB. ' NOBBOLKt,— 50 NW*, NE* 64*, 65*, 66*, 67*, 68* 69. NORTHAMPTONSHIRB,— 64* 46 NW, NE, 48 NW, 52 NW NB, SWj 53 NB, SW, & SB, 63 SE, 64. NORTHUOBBRLAND,- 102 NW, NE, 105, 106, 107, 108* 109 110, NW», SW* NB* SB. NOTTIN6HA1|^70*, 71* NB. SB, NW, 82 NE* SB* SW 83 86,87*SW.' : > . , I OXFORDSHIRE,- 7* 13* 34* 44* 45* 63 SB* SW PBMBROKESHIRBt,— 38, 39, 40, 41, 58. RAPNOHSHIRfi,— 42 NW, NE, 56, 60 SW, SE. RUTLANDSHIRE,- this county is wholly included within Sheet 64*. SHEOPSHIRB,-55 NW. NE, 56 NB, 60 NE, SE, 61, 62 NW ' 73,74NB,SE. , ' SOMERSETSHIREt,— 18, 19, 20, 21, 27, 35. STAFFORDSHIRfi*,-64 NW, 65 NE, 61 NE, SE, 62 63 NW 71 SW, 72, 73 NE, SE, 81 SE, SW. ' ' SUFFOLK,— 47», 48* 49*, SO*, 51*, 66* SB* 67* SURREY,- 1 SWt, 6t, 7*, 8t, 12t. SUSSEX,— 4*, 6t, 8t, 8t, 9t, lit. WAS,WICKSH:irE,-44* 45 NW, 53* 54, 62 NE, SW SB 63NW, SW,SE. . s=w, BJi, WBStMORLASB.-S? NW*, SW* 98 NW NE* SE* 101 SE*, 102. ' ' ' WILTSHIRE,-12*, 13*, 14, 15, 18, 19t, 34», and 35t WORCESTBRSHIRB,-43 NE, 44*, 64, 66, 62 SW, SE, 61 SB. YORKSHIRBt,-86-88,91NE,SE92*7* 98 NK» SB* IftSNU SE, 103 SW, SE, 104 . ' Plate I. Hanging Rocks, Woodhouse Eaves. Crag of Woodhouse Beds, shewing Bedding and Cleavage in hornstones, From a Photograph by Dr F ] Allen. -n-li 1S5 MEVlOmS OF THE GEOLOGICAL SURVEY. ENGLAND AND WALES. THE GEOLOGY OF THE OOUNTEY BETWEEN ATHERSTONE AND CHARNWOOD FOREST. (Explanation of Sheet 155.) C. FOX-STRANGWAYS, F.G.S. WITH Notes on Charnwood Forest by Professor W. W. Watts, M.A., F.G.S. ITBLISHKl. lit OllUKR OV THE LOKDS COMMISSIONERS OP HER MAJESTY'S TREASURY. LONDON : PlllNTED FOK HEE MA.JESTY'S STATIONERY OFFICE, By WYMAN and SONS, Limited, Fetter Lane, E.C. And to be ijurchased, either directly or through any Bookseller, from KYRE & SPOTTISWOODE, East Harding Street,' Fleet Street, E.C JOHN MENZIES & Co., Rose Street, Edinburgh, and 90, West Nile Street, Glasgow ; or HODGES, FIG(;iS, & Co., Limited, 104, Graftos Street, Dublis. 1900. Price Two ShUliiigs. 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/cu31924004550236 PEEFACE. The ground desci-ibed in the present Memoir is contained in Sheet 155 of the New Series of the one-inch-scale map of England, and embraces the western part of Leicestershire, with adjacent portions of Warwickshire, Staffordshire, and Derbyshire. It nearly coincides with the area represented-in Sheet 63 N.W. of the Old Series map of the Geological Survey, which was surveyed by Mr. H. H. Howell and Prof E. Hull, and pubhshed in 1855. A memoir descriptive of this gi-ound, prepared by Prof. Hull, was published in 1860 under the title of " The Geology of the Leicestershire Coal-field and of the Country around Ashby-de-la- Zouch." A small portion of the area depicted on the new map (Sheet 155) was comprised in the quarter-sheet 63 S.W. of the Old Series, and was illustrated in the Memoir on " The Geology of the Warwickshire Coal-field " by Mr. Howell, which appeared in 1859. Another smaller Memoir on " The Geology of part of Leicestershire," by Mr. W. T. Aveline and Mr. HoweU, wliich described the quarter-sheet No. 63 S.E., was published in 1860. The whole region having to be re-examined for the mapping of the superficial deposits, which were not shown upon the old maps, advantage was taken of the opportunity to revise the survey of the underlying formations. A comparison of Sheet 155 of the New Series with the former quarter-sheets of the Old Series which it replaces, will show that considerable changes have been made in the delineation of the geology of this part of the Midlands. The employment of the Ordnance maps on the scale of six inches to a mile has made it possible to introduce more detail and to ensure greater accuracy than was attainable with the smaller scale. For the first time the ancient rocks of Charnwood Forest, so carefully studied by Prof Bonney and the Rev. E. Hill, have been worked out in such a manner as to allow their various sub-divisions to be represented on a published map. The Cambrian rocks of Nuneaton, formerl}- supposed to be of Carboniferous age, but proved by Professor Lapworth to be of much older date, were revised by Mr. A. Strahan in 188C. The main sandstones in the Coal-measures near Atherstone have been mapped, while the thin-bedded character of the Keuper Sandstone is now more clearly repre- sented. The Trias is shown to have buried the ancient peaks of Charnwood Forest much more widely than was represented on the older maps. Some doubt remains regarding the correlation of the deposits coloured on the map as Permian. Some of the sand- stones in the extreme south-west corner of the map, hitherto shown as Permian, are for the present bracTteted with the Carboniferous formations, but when a larger area of them has been mapped they may possibly require to be relegated to the 3288. Wt. 28S44. 500— 12/00. Wy. & S. a rREFACE. Trias. In like manner the age of the breccia that surrounds the Leicestershire and South Derbyshire Coal-field has not been determined. For the first time the superficial deposits in this central part of England have been surveyed in detail and are shown upon a published map. Their plateau-Uke character forms a striking feature in the region. The alluvia of the various streams are now represented on the map, which thus brings out with great clearness the drainage-lines. The whole of the map has been surveyed by Mr. C. Fox- Strangways, except the area of Charnwood Forest, which has been mapped by Mr. W. W. Watts. The present Memoir has been prepared by Mr. Fox-Strangways, Mr. Watts supplying the brief account of the pre-Cambrian rocks of Charnwood Forest, which forms the second Chapter. It is intended that fuller descriptions will afterwards be given of some of the rocks enumerateci in the present Sheet-Memoir. Thus, Mr. Fox-Strangways will prepare an account of the Leicestershire Coal-field, and Mr. Watts, who has resigned his position in the Geological Survey to become Assistant Professor of Geology in the Mason University College, Birmingham, has kindly undertaken to supply a full narrative of his researches in Charnwood Foi*est. It should be mentioned that manuscript copies of the six-inch field maps are deposited in the Geological Survey Office. For much information with regard to the Coal-fields we are indebted to Mining Engineers, Colliery Managers, and Surveyors, who have freely given access to plans and sections. ARCH. GEIKIE, Geological Survey Ofiice, Director-General, 2,8, Jermyn Street, London. 9th July, 1900. CONTENTS. PACiE. Preface by the Director-General iii Chapter I. — Intkoddction. General description of -the district, Classification, and Table of Strata, Economic products - 1 Chapter II.— Pee-Cambeian PiOcks of Charnwood Fop.est. By Prof. W. W. Watts. Classification, Structure, The Black- brook Series, The Maplewell Series, The Brand Series, Fo,-sils, Intrusive Rocks, Correlation, Landscape -t Chapter, III. — Cambrian. Stockingford Shales and Intni-^ive Igneous Rocks, List of Fossils ' I Chapter IV. — Carboniferous. Coal-measnres. The Northern Outcrop of the Warwickshire Coalfield 1 •"> Chapter V. — Carboniferous (continued). Coal-measure, (con- tinued). The Southern Part of the Leicestershire (Joiltield 21 Chapter VI. — Permian. Doubtful correlation of the Warwick- shire Rocks, Breccia of Leicester.shire 2S (Jhapter ^'II. — Trias. Bunter Sandstone and Pebble Beds, Lower Keuper Sandstone, Keuper Marl -52 Chapter VIII. — Pleistocene and Recent. Glacial Depiisit^, Post-Glacial Deposits, Alluvium 3' Chapter IX. — Faults. The Warwickshire di^trirt. The Leicester- shire Coalfield - - -11 Ai'PENDix I. — Sections in the northern part of the Warwick- shire Coalfield 47 Appendix II. — Bibliography. List of Works on the Geology of Leicestershire, with the addition of a few referring to the immediate neighbourhood of this district. By C. Fox- Steangways, aided by W. Whitakee 70 Index - '■>'^ LIST OF ILLUSTRATIONS. Plate I. Crags of Hornstone in Hanging Rocks Grounds, Charn- wood Forest. Photograph by F. J. Allen, Frontispiece. Plate II. Volcanic agglomerate in Charnwood Forest; and^ y,^ Section in Charnwood Forest, showing unconformable I j-'' junction of Triassic marl resting in an old valley ( "{, q excavated through the ancient (pre-Cambrian) slates J ^' ' Y'm. 1. Section across the northern edge of the Warwickshire Coalfield ■ - \i „ i. Comparative Section of Coal Seams in the extreme north of the Warmckshire Coalfield - To face p. 1(J „ 3. Diagram .showing position of Strata on the east side of the Ashby anticline 22 „ 4. Plan of the East Leicestershire Coalfield showing supposed extent of the Whinstone • 24 „ Hf. Diagram showing position of Strata on the west side of the Ashby anticline -i.'i THE GEOLOGY OF THE COUNTRY BETWEEN ATHERSTONE AND CHAENWOOD FOEEST. CHAPTER I. Introduction. This sheet comprises an area of 216 square miles, the larger part of -which lies in the County of Leicester, but it contains also portions of Derbyshire, Warwickshire, and a small part of Staf- fordshire. It includes the greater part of the area shown in 63 N.W. of the old survey, but extends somewhat farther to the east, west, and south, although not so far to the north as that map. Owing to the Drift, which overlies the more solid rocks, being now shown, this sheet has far more detail than the older maps. Some of the other formations are also further sub-divided, par- ticularly the older rocks of Charnwood, showing the structure of this region in a manner that has not previously been attempted.* Six-inch maps being now employed for the fieldwork, it has been possible to trace the boundaries with greater detail. Since the old survey several new collieries have been established, and the workings of the old mines have been considerably extended, so that much additional information has been obtained, that has in all cases been readily put at our disposal. This has thrown much new light on the structure of the rocks, and has enabled many points to be determined with greater accuracy than was possible nearly fifty years ago. There are no very important towns in this sheet. The princi- pal places are Ashby-de-la-Zouch, Coalville, and Atherstone. It also includes the old town of Market Bosworth, and there are numerous villages, many of which, especially near the mining districts, are of considerable size. The drainage of the coimtry is entirely within the basin of the Trent, but locally it is separable into two districts drained by the tributaries of that river ; the one by the Soar and its branches flowing east ; the other by the Mease and the Anker, which flow * The Charnwood rocks were very fully described by Messrs. Hill and Bonney in the " Quart. Journ. Geol. Soc," vol. xxxiii., p. 754 ; vol. xxxiv., p. 199 ; xxxvi., p. 33 ; vol. xlvii., p. 78 ; but no attempt was made to map the structure of the country until the present survey was undertaken. The first results of which were brought before the Brit. Assoc, at Liverpool in 1896 by Mr. W. W. Watts, and published in the " Geol. Mag.," dec. iv., vol. iii., p. 485, 1896. 3288. A 2 INTRODUCTION. west. The watershed dividing these two areas passes first in an easterly direction across the map from the high ground east of Ashby by Coalville and Bardon Hill to Copt Oak ; and then more southerly by EUistown, Bagworth, Cadeby, Stapleton, Barwell, and Hinckley. The highest ground is over the Charnwood Forest district, which at Bardon Hill attains an elevation of 912 feet above the sea. At the foot of these hills, which rise abruptly, there is an extensive plain gradually declining from about 600 to about 400 feet above the sea, which is deeply cut into by the numerous small streams intersecting this plateau. In the western half of the map, between the two Coalfields, where the Drift has been denuded, the plateau-like character has been destroyed, and sharp escarpments are formed by the harder beds of the Permian, Bunter, and Coal-measure sandstones. The greater part of the surface is covered by the Keuper Marl ; which, over the higher ground, is much hidden by Boulder-clay and gravel. The Coal-measures, which cover the next largest aifea of surface, are separated into two portions forming part of the Warwickshire and Leicestershire Coalfields respectively : the connection between them is hidden beneath a broad belt of Lower Keuper Sandstone. The only other strata, that cover any considerable extent of ground, are the old rocks of the Cham- wood Forest district. These, which form some of the most lofty ground in the Midlands, have been denuded into a series of isolated hills ; the hollows between which have, in nearly all cases, been filled in with Keuper Marl. The other rocks which crop out, the Permian and Bunter sandstones, and the Cambrian shales of Atherstone with associated igneous rocks, do not occupy any large extent of surface. The following formations occur in the area :. — Kecent and JfU^vium ^ ^ Glacial /Newer Boulder-clay, Sand and Gravel. \01der Boulder-clay, Sand and Gravel. ^ f Keuper - /keuper Marl with lenticular sandstone beds, g ] \ Lower Keuper Sandstone with marl bands. H L Bunter - - Pebble Beds or Conglomerate, and Sandstones. Pebmian Breccias with Marls. fUpper Coal Measures -f^^f^^o'^.f;,*'"! ^^rls* CARBomifFTjnTTs-^ T ^ (.bnaies with (S^irorois Limestone. UAEBONiFEEOUsSLg^gj. Coal Measures-Clay- and sh£es with beds of I Sandstone and Ironstone, and numerous coal seams. Cambrian- Shales with intrusive igneou? rocks. Pbe-Cambeian/ Slates, hornstones, and agglomerates with intrusive or Aech^an • - ^ Igneous rooks. The soil of the country is mainly dependent upon the under- lying formations. Thus the alluvium and some of the Drift beds form the best pastures, while the best corn land is found over the Keuper Marl. Owing to the large proportion of friable soil . * These beds were formerly regarded as of Permian Sige. See page 28* They are represented on the map by a mixture of the Permian and Coal- measure colours. • ■ . INTRODUCTION. 3 especially over the Keuper Sandstone and the Pebble Beds, there is a much larger extent of arable land in this part of the country than in the east, and we do not find the large grazing districts that occur on the Lias. In the Charnwood Forest area, owing to the rocky character of the ground, only the valleys and flanks of the hills can be cultivated, the summits being either woodland or rough moorland. The principal industry of the district is coal mining, which is now being vigorously carried on in the three separate districts of Baddesley and Polesworth ; Moira, Donisthorpe, and Netherseal ; and between Whitwick and Bagworth. Other important indus- tries are the quarrying of the igneous rocks for road-stone and pavements, which is carried on at Whitwick, Bardon HUl, Cliffe Hill, Markfield, Groby, Enderby, Narborough, Croft, and south of Atherstone, while flagstones are made of this material at Groby and Croft. The output from these quarries has enormously increased during recent years, very large quantities of broken stone being sent away for macadamising roads, and the manufac- tured flagstone is rapidly superseding the natural material. There are important brick and terracotta works in the Lower Keuper beds at Coalville, EUistown, Ibstock, Heather, and Measham, and in the pot and fireclays of the Coal Measures to the north of Moira. These latter have of late years come into very extensive use, and a large industry in the making of sanitary pipes has arisen throughout the district between Moira and Swadlincote. A rough slate is obtained from the Charnwood rocks at Swith- knd and Groby, but it is much inferior to the Welsh slates, and since the introduction of railways these workings have been entirely abandoned except to a very small extent at the latter place. Manganese was formerly worked in the Stockingford Shales to the south of Atherstone ; and limestone in the Coal-measures near Baddesley, but never to any extent. There is no building- stone of any value. The soft sandstone* of the Lower Keuper, the Bunter, Permian, and Coal-measures have been used for this purpose ; but, except in a few cases, they are far too soft to stand the weather. The slates and igneous rocks of Charnwood are occasionally used for rough or irregular walling. The use of the Drift gravel, which occurs over a large area, is now almost entirely superseded by that of " granite ' for road mending ; but the Pebble Beds of the Bunter are still worked, to a small extent, at Polesworth for this purpose. The chief water-beanng stratum of the district is the Lower Keuper Sandstone, the porous divisions of which contain a very large amount of pure water. At EUistown these rocks yield as much as 390,000 gallons a day. There are also many large springs issuing from the glacial gravels throughout the district. These also yield a very pure water, but in populous districts it is more liable to contamination than that from the deeper-seated sandstone. 3288. 4- PRE-CAMBRIAN. CHAPTER II. PRE-CAMBRIAN. Pre-Cambrian Rocks of Charnwood Forest. By Peofessob W. W. Watts. On the north-east corner of sheet 155, scattered over an area of about seventeen square miles, there occur a number of rock- masses which are the summits of an old mountain range, whose base is buried deeply under the Trias. These rocks rise to their highest point in Bardon Hill, 912 feet above sea-level, but there are other hills of considerable height, such as Birch Hill and Beacon Hill, both over 800 feet, and Peldar Tor, over 700 feet. This region is Charnwood Forest and its rocks are the oldest known in the district. They consist of a thick mass of clastic volcanic rocks, with overlying grits and slates ; they are intruded upon in places by several types of igneous masses, and the whole of them are of pre- Cambrian age. SUCCESSION. The chief local divisions, several of them first indicated by the Rev. Edwin Hill and Prof. T. G. Bonney, and subsequently estab- lished and mapped by the Survey, are the following, given in descending ord!er : — f(c) Swithland and Groby Slates. (C) The Brand Series Hh) Conglomerate, Grit, and Quartzite. i(a) Purple and Green Beds. .(e), Olive Hornstones of Bradgate. (d) Woodhouse Beds : Hornstones and (B) The Maplewell I Volcanic grits. Series (c) Slate- Agglomerate of RoecUffe. (b) Hornstones of Beacon Hill. Ha) Felsitic Agglomerate. (A) The Blackbrook Series : Hornstones and Volcanic grits. The succession is clearest in the eastern part of the district, but It becomes much confused in the north-west, partly on account of the mcreased faulting and disturbance, but chieflv on account of the fact that the focus of volcanic activity appears to have been situated m or near this region. STRUCTURE. The general structure of the Porest is an elongated semidome rbib H "^^^"l Tu ^T^'l, ^■"^- ^^-^ S.E.; round this the chief beds can be followed and mapped. This simple structure IS however, much complicated by faulting, which fofiows on the whole the lines estabhshed by mapping and mining in the, PRE-CAMBRIAN. > 5 Leicester Coalfield. The main set of faults course N.W. and S.E. and the most important of them is the well-known anticlinal fault, extending from near Charley Knoll, through Bawdon Castle, Benscliffe, and near Warren Hill (W.) into Hallgate Hill spinney. East and west of this are other thrust-faults which repeat the beds, showing that the flanks of the arch have been thrust over its keystone. One of the faults following this course from north of Woodhouse Eaves and through the Brand, is a normal fault, concealing some of the higher beds in the Maplewell series. The cross faults run N.E. to S.W., or E.N.E. to W.S.W. ; the chief of them skirts the north side of Bardon Hill; a smaller one occurs south of Birch Hill and appears to run out north of Woodhouse Eaves ; and a third forms the southern margin of Peldar Tor. The principal beds, especially Cc, Cb, Be, and Ba can be traced from their first entry into the area, between Whittle Hill and the Hanging Rocks near Woodhouse Eaves, round the southern side of the anticline to Timberwood Hill and Warren Hill (W.), where their individuality becomes lost. Their outcrop is frequently shifted by faulting, and the beds are often lost sight of altogether on account of faulting or the overspread of Trias, but, where one bed is lost, another one near to it can usually be followed. The structure sketched out in the foregoing paragraph seems to be that which best explains the position, dip, and strike of the exposed rocks, and it is confirmed by an attentive study of the local succes- sion which may here and there be obtained among the crags and scarps. SUBDIVISIONS. The Blackbrook Series.— It has not been found possible to sub- divide this series, partly on account of the paucity of exposures, and partly because of the monotony in type of the rocks. Immediately under the Felsitic Agglomerate of Whittle Hill come some exceedingly fine-grained, hard, tuft's, which are quar- ried as the far-famed Charley Forest " Hone-stones." Under it there is a thick set of fine buff or green ashes, often beautifully banded, fine-grained and flinty, so that they have almost the aspect of felsites, and were considered to be quartzites by Jukes. One coarse band of conglomeratic grit is traceable for some miles in the sheet north of 155, but it is only seen in this sheet near the farm called Rock Villa. The joints in the rocks of this series are generally stained red with oxide of iron, and some bands contain well-developed cubes of haematite, pseudomorphous after pyrites. The Maplewell Series.— These rocks are best seen extending from about Beacon Hill, through the grounds of Maplewell Hall, and thence to Bradgate Park. They admit of the following sub- divisions. The Felsitic Agglomerate. — At Whittle Hill a coarse agglome- rate is found below the Beacon Hill Hornstones, which contains fragments of felsite as well as andesite, and but very few or no slate fragments. This we have called the Felsitic Agglomerate. Probably owing to faulting it is soon lost, but fragments of it 6 , PRE-CAMBEIAN. are abundant all about Black Hill, and it probably occurs in siUl in a spinney near the road just a quarter of a mile west ol Bawdon Castle. It is caught in the anticlinal fault m Orreen Hill and Benschffe Wood, and shattered to pieces m bending round the curve of the dome. It is found also near Chitterman HiUs, and probably runs through Irish Farm towards Abbots Oak. Faulted back from this point, it appears in force on the east margin of Timberwood Hill, and from thence it is tmce- able through CoUier Hill to the margin of the map on Flat Hill. A pecuhar character of the rock is that wherever it_ is exposed it has an exceedingly rough surface, which, however, is not due to the picking out of the fragmental constituents of the rock ; indeed, its fragmental nature is best seen on a freshly fractured surface. It is generally jointed at right angles to the bedding and breaks up into pillar-like masses. This rock forms a convenient base to the Maplewell Series. The Beacon Hill Hornstones are fine green or cream-coloured ashes with occasional grit-bands a few feet thick, generally quartzose and epidotic. They give rise to very characteristic exposures on Beacon Hill and to the northward, and they may be traced round at intervals to Ulverscroft. They are not well exposed on the south-west side of the Forest, and when traced to the north-west and beyond the Bardon Hill fault they appear to pass into a great series of coarse breccias and volcanic agglo- merates, in which it is not possible to trace out a sequence in consequence of the absence of all bedding below the higher hornstones and breccias of Warren Hill (W.). These rocks, how- ever, appear to be the equivalent in time of the Beacon Hill Series, but they must have been deposited quite close to the volcanic vent, while only the finer materials drifted on the wind so far away from the vent as the eastern and southern sides of the Forest. If the correlation of the rock on the south of the great quarry on Bardon Hill with the Slate-Agglomerate is correct, the mass of rocks in the Hill, so largely quarried for road- metal, must also be the equivalent of the Beacon Hill Hornstones and of the great agglomerates of Charnwood Lodge and the rest of the district between Timberwood Hill and Warren Hill (W.). The Bardon Hill rocks appear to be in the main of clastic origin as, even in those varieties which are most like lavas or intrusive rocks, bombs or angular fragments can usually be detected: the only exception known to me is the " porphyroid " of the north flank of the Hill and quarries. It is possible that some lavas or intrusive rocks may occur here, but it has not been found possible to separate or recognise them, with the exception of the porphyroid just mentioned. The Slate-Agglomerate. — Underlying the last division there is a marked band of volcanic agglomerate, named by Messrs. Bonney and Hill the Slate-Agglomerate, because of the abundance of slate fragments which are mixed with lapilli of andesitic rocks, and with broken felspar and quartz crystals. Some of the slate fragments seen in Bradgate Park and Warren Hill (E.) are from four to six feet long, and they are often folded. This band is PRE-CAMBRIAN. 7 traceable at intervals from the foot of the Hanging Rocks through the Brand, Roecliffe, Bradgate Park, the " Altar Stones " at Mark- field, the Hollies, probably to Bardon Hill and the western flank of Warren Hill ( W.) * The Woodhouse Beds consist of alternations of coarse and fine volcanic ashes, the former giving rise to grits, highly felspathic and often quartzose, the latter to fine, banded, green, siliceous homstones generally weathering to a cream colour. They are well exposed in the grounds of the Hanging Rocks north of Woodhouse Eaves,-|- and after sweeping through Bradgate and the country near Markfield they are well exposed in the crags above Rice Rocks Farm. The Olive Homstones of Bradgate. — The highest rocks of the Maplewell series occur in force m Bradgate Park, whence they extend into the area of the adjoining map to the east. They are fine olive-green homstones devoid of coarser seams, but ashy in composition, and more or less fissile or slaty. They appear to be faulted out of the eastern side of the district from Woodhouse Eaves to Roecliffe and the Brand. It is likely that these rocks are several times seen on the west side of the Forest as in the old quarry below Rice Rocks Farm. The Brand Series consists largely of rocks deposited under water, the materials being chiefly terrigenous, and derived from the denudation of sedimentary and volcanic rocks, but volcanic intercalations are not at all frequent. The Purple and Green Striped Slaty Beds are only recognised in a few localities such as Woodhouse Eaves and the Brand, and they are mapped with the Maplewell Series, the conglomerate being used as the most convenient base for mapping the Brand series. The Conglmnerate and Quartzite division is well seen in the Hanging Rocks, the grounds of the Brand, and the N.E. entrance of Bradgate Park. The conglomerate occurs in beds from a few inches to a couple of feet thick ; the pebbles may be three or four inches long, but they are usually smaller, and they are made of quartzite, vein-quartz, and slaty rocks ; the whole rock is much crushed and cleaved, the long axes of the pebbles being often parallel to the cleavage planes. Above the conglomerate there is usually a thick band of purplish black grit, very rough to the touch and easily recognised. Some bands of this are highly quartzose, and pass into quartzite at Woodhouse Eaves and the Brand. The quartzite gains in strength and importance in Bradgate Park, Lady Hay Wood, and in New Plantation, about a quarter-mile W. of Bradgate House. The Swithland Slates are purple or green in colour, often satiny and glossy, but the cleavage is somewhat coarse, and the slates, which were at one time much worked for roofing and slabs, are thick and heavy but very durable. The chief quarries were at Woodhouse Eaves, The Brand, Swithland Wood, and the " See Plate II. t See Frontispiece. PRE-CAMBRIAN. country between Groby and Markfield ; similar slates were also worked near Bardon Lodge. FOSSILS. The only fossils hitherto collected from the area are some worm burrows, the first of which were found by Professor Lapworth in beds on about the horizon of the quartzite or lower slates of the Brand Series in Bradgate Park. Mr. Rhodes has subsequently found other specimens in the same locality. INTRUSIVE ROCKS. Three or four types of intrusive rocks are met with in the part of Charnwood Forest included "in this sheet. Porphyroids. — These rocks occur in their most tjrpical aspect at Peldar Tor and Spring Hill, and on the northern flank of Bardon Hill. The dommant type of rock is a porphyritic quartz- andesite or dacite, with large crystals of quartz and plagioclase in a fine-grained matrix. Its relationship to the other rocks in the Peldar area is not clear, but the difficulties which surround its method of occurrence would probably be best explained by supposing it to be intrusive. Messrs. Bonney and Hill regard it as a contemporaneous set of lavas. Whatever may be the relations of the rock of Peldar Tor, the precisely similar rock on Bardon Hill is undoubtedly intrusive, as its junctions with the compact agglomerate of Bardon are exposed along the north side of the great quarries. The junction is irregular, the rock has a chilled margin, it has reddened and altered the Bardon rock in contact with it, and it includes pieces of that rock. A close-grained felsitic rock, much crushed, is found on the Warren Hill Moor- land, just south of Charnwood Forest Farm. A porphyroid without quartz, but with porphyritic felspar, occurs at Birch Hill ; and another near Alderman's Haw, and at one or two other localities quite near to it on the north flank of Beacon Hill. These rocks appear also to be intrusive, though certain proof of this relationship is wanting. All the porphjToids are crushed and sheared by the main N.W. and S.E. movements, and they were intruded before this movement began. Fragments undistinguish- able from some of the varieties of the porphyroids are to be found in many of the agglomerates of the north-west region. Augite-Syenite. — Another important group of intrusive rocks are augitic granophyres or augite-syenites. They are generally found along the N.W and S.E. fault planes as at Bawdon Castle and HammercHffe, or else swelling out into large kernel-like masses such as those of Newtown Linford and Bradgate Park, Groby, Bradgate Woods, Markfield, Cliffe Hill, and Stanton-under- Bardon. The rocks are much altered and full of epidote, but they appear to have originally contained hornblende, augite, orthoclase, and plagioclase, embedded in a granophjrric ground- mass. They consolidated under plutonic conditions and appear to bear no direct relationship to the porphyroids or the con- Plate II. %^' •-•ift* Vo/raiiic (if/(/lomer(tte in Charnimod Forest. Tlie large bombs have been turned, on end or squeezed flat by the pressure whicb has cleaved the rock. From " Geology for Beginners," by W. W. Watts (Maomillau & Co.), 1898, Fig. 104, p. 153. Sectldii in Gharnwood Foivst ; showing unconformable junction of Triassic marl (/), resting in an old valley excavated through the ancient (pre-Cambrian) slates (x). From " Geology for Beginners," Fig. 155, p. 222. 3288. (To face page 9) PBE-CAMBRIAN. 9 stituents of the agglomerates. The southern group of syenites is somewhat more acid than the northern, and the rocks bear evidence of having suffered from earth-movement, so that the thinner masses are much crushed. The northern group is more basic, darker, denser, and harder, and as it came up along the fault-planes it is later in date and is not affected by the movement; indeed it has come up along the fault-planes developed in the later stages of the movement. Similar syenites emerge from beneath the Trias at Enderby, Croft, and elsewhere to the south, and near the former place they are in contact with slates of Cham- wood type. These rocks are much quarried everywhere for paving setts and road metal. They must be distinguished from the diorites or camptonites of the Warwickshire district, with which they have little or nothing in common. AGE AND CORRELATION. The Charnwood rocks are not at all like the Cambrian rocks of the Nuneaton district, nor are they like the felspathic tuffs and breccias which underly them. It is useless to parallel them with anything more recent than the Cambrian System and they are not like the Uriconian or Torridonian rocks, unless we except the grits and conglomerate of the Brand series, which have some resemblance to the Torridonian rocks. On the other hand, they have nothingin common with the gneisses and schists of the North- west or Central Highlands of Scotland. Many of the individual bands are like those of the Longmynd, in Shropshire, and, indeed, if we could imagine the pyroclastic materials from the Charn- wood volcano dropped far from the vent and sorted and stratified in water, they would be likely to produce a group of rocks much like those of the Longmynd. It is impossible at present to push the comparison further, and meanwhile it may be better to be content with naming the whole group the Charnian System, and to refer it to some unascertained position in the great pre- Cambrian sequence. RELATIONSHIP TO THE TRIAS. In the sheet under consideration the Keuper Marl is the only newer rock found in contact with the ancient rocks of the forest. The unconformable junction is seen at several places. At Bardon Hill and elsewhere, the ancient rocks plunge down with a steep slope under the marl. A small breccia fringe is sometimes seen at the junction, but it never extends far from the old rock ; some of the bands of skerry are made up of Charnian debris. At Bardon Hill, in the slate quarry at the south end of the Hanging Rocks, and in the slate quarry in Swithland Wood, near the Brand, the marl is found filling up old valleys in the slates or agglomerates. One of the junctions is shown in the annexed figure.* " See Plate II. 10 PRE-CAMBRIAN. LANDSCAPE. The earth-movement which folded, faulted, and cleaved the rocks of Chamwood Forest, and guided the intrusion of igneous rocks into them, appears to have been of pre-Cambrian date, as no such effects are produced in the neighbouring Cambrian rocks of Nuneaton. After this mountain-making movement, which in places has converted the porphyroids into augen- chlorite-schists, the region was subjectea to marine and sub- aerial denudation, possibly several times before the Carboniferous Jferiod. During Carboniferous Limestone times some sub- mergence and deposition took place on the northern skirts of the Forest, but it was not until Triassic times that the whole of the old mountain chain was completely enveloped in sediment. It is quite possible that the very highest summits were not even then covered. But the finishing touches to the landscape forms of the rocks were executed in Triassic times, and as the majority of the rocks are only just now being uncovered they still present a scarcely altered Triassic landscape. To this day many of the summits are as rugged and precipitous as when they were mountain-tops overlooking a Triassic desert or just submerged beneath the waters of a Triassic lake. w. w. w. CAMBRIAN. 11 CHAPTER HI. CAMBRIAN. Besides the great mass of strata which form the Charnwood Hills, there is another small area of old rocks, which just comes into the map to the south of Atherstone. This is the northern extremity of the outcrop that extends along the hill from Bed- worth, south of Nuneaton, to Waste HiU, Beyond Atherstone, a distance of nine or ten miles. These beds, known as the Stockingford Shales*, were originally mapped as Carboniferous, having been supposed to represent the lower or unproductive part of the Coal-measures ; but in 1882 Prof Lapworth brought forward convincing proof that they must be of Cambrian age.f The history of this error, how it arose, and the views entertained by authors at different times, has been clearly given by Mr. Strahan in his account of these rocks,t so that we need not pursue the subject further here. The Cambrian rocks of this district consist of red, purple, olive- green, and grey shales, with a few dark carbonaceous bands ; and, allowing an average dip of a little over 20°, have a thickness of about 2,000 feet. They are separable into two main sub- divisions : a lower series of purple, green, and grey shales, with many small Brachiopoda of the genera Lingule-Ua and Obolella, and an upper series of grey shales, with black bands, containing Agnostus and Olenus. These shales are well laminated, but not in the least cleaved, and dip to the south-west at angles varying from 15° to 35°. They are traversed by numerous parallel dykes of diorite,§ which give rise to the broken, undulating ground south of Atherstone, forming some of the prettiest scenery in the map. These sheets of igneous rock, although they are really intru- sive, follow the line of strike so closely that at first sight they appear to be interbedded with the shales. That they are intru- sive, however, may be seen by the baked nature of the shales near the line of contact, and more clearly in the quarry south of Merevale Church, where the shales are dipping 15° to the south- west, while the igneous rock inclines at an angle of 35° in the same direction. * This name was first suggested by Mr. W. Jerome Harrison, from the locality where these beds are best shown. t Geol. Mag. dec. ii., vol. ix., p. 563, 1882 ; and dec. iii., vol. iii., p. 319, 1886. There is also a full account of these rocks by Prof. Lapworth, with an appendix by W. W. Watts in Proc. Geol. Assoc, for August, 1898, vol. XV., part ix. t Brit. Assoc. Eep. for 1886, Trans, of sections, p. 624 ; and Geol. Mag. dec. iii., vol. iii., p. 540, 1886. § For description of this rock see Allport, Quart. Journ. Geol, Soc, vol. XXXV., p. 637, 1879. 12 CAMBRIAN vi a bo m UJ 2 5 O 2 «&•' ^ i§^ 0.W />yi-r .\ \ \ M 61- u O EQU 555551 CAMBRIAN. 13 The outcrop of the Stockingford shales is, from the absence of Drift, generally very clear, and may be followed without much difficulty. The best sections, are, however, just beyond the edge of the map at the quarry below Oldbury Reservoir, and in the lane and new drive at Purley Park. Professor Lapworth has separated these shales into three series. The Lower, or Purley Shales, formed of brightly coloured pv/rple mudstones and shales, occur along the lower part of the Outwoods ; the Middle or Oldbury Shales, formed essentially of black shales, enter the map in Merevale Park ; and the Upper or Merevale Shales, formed of grey shales, are found near the road south of Merevale Abbey.* The sheets of igneous rock vary from dykes, having a thick- ness of 200 yards or so, to mere strings of rock which cannot be traced. They obtain their greatest development in Merevale Park, in the thick mass immediately south of the hall ; but the outcrop is not so extensive, and is more split up into thin sheets and strings, than shown in the old map. It is not, however, easy to follow the outcrop of these thin beds in the woods south of the park. The composition of the diorite (camptonite) has been so ably described by Allport,f Teall,;]: and Watts,§ that it is needless to give a detailed description of it here. The predominant and characteristic constituents are a triclinic felspar and hornblende, together with a little magnetite and apatite ; a glassy or fels- pathic matrix is also nearly always present. The following fossils have been obtained from the shales : — LIST OF FOSSILS FROM THE STOCKINGFORD SHALES. || Sponges. Hyalostelia [ = Pyritonema]. Protospongia fenestrata. Salt. Crustacea. Agnostus cf. cyclopyge, Tullberg „ pisiformis, var. socialis, Linrs. Beyrichia Angelini, Barr. „ cf. nana, Brog. Conocoryphe ? coronata, Barr. Ctenopyge pecten, Salt. Leperditia cf. primordialis, Linrs. Olenus nuneatonensis, Sharman „ cf. Salter i. Call. Sphasrophthalmus alatus, Boeck. * Proc. Geol. Assoc, vol. xv., p. 345. t Quart. Journ. Geol. Soc, vol. xxxv., p. 637. J British Petrogx-aphy, pp. 133, 251, and Plate xxix. § Proc. Geol. Assoc, vol. xv., p. 394. II This includes all the species given by Prof. Lapworth in his amended List (Proc. Geol. Assoc, vol. xv., p. 348, 1897), where details of the localities will be found. 14 CAMBRIAN. Bryozoa. Dictyonema sociale, Salt. Brachiopoda. Acrothele granulata, Linrs. [ = Obolella granulata, Sfiar- man] Acrothele cf. A. intermedia, Linrs. sp. cf. Kutorrina ? pusilla, Linrs. Acrotreta sp. [ = Obolella Sabrmse ? SJiMrman] Kutorgina cingulata, Billings „ labradorica, Billings ' Lingula sp. [ = L. lepis ? Lingulella Nicholsoni, and L. pygmsea of earlier lists]. Obolella cf. sagittalis, Salt. „ Salteri, Roll. Orthisina cf. transversa, Wahl. Mollusca. Coleoloides typicalis, Walcott Hyolithus cf. lenticularis, Holm „ „ obscurus. Holm „ „ princeps, Billings „ „ tenuistriata, Linrs. Orthotheca communis, Billings „ corneola ? Holm de Geeri, Holm Johnstrupi, Holm „ cf teretiuscula, Linrs. Stenotheca rugosa, Walcott „ var. abrupta, Walcott Scenella sp. COAL MEASURES. 16 CHAPTER IV. CARBONIFEROUS. Coal Measures. THE NORTHERN OUTCROP OF THE WARWICKSHIRE COALFIELD. The Coal-measures which outcrop in this map form two separate districts, one comprising a portion of the northern part of^the Warwickshire coalfield, the other the southern part of the Leicestershire and South Derbyshire coalfield. These will be described at greater length, when the whole ground has been surveyed, in special memoirs treating of these two coalfields respectively, so that in the present case we propose merely to give an outline of the structure of as much of the ground as falls within the limits of this map. Whether these two coalfields are connected beneath the over- lying Trias is at present scarcely decided, but the evidence, as far as it goes, is against the supposition that such is the case, or that coal will be found over much of the intervening ground. That portion of the Warwickshire Coal-measures with which we have to deal is the eastern side of the northern half of the coalfield, and includes an area of about seven square miles in the south-west corner of the map. It contains at the present time four working collieries, which have afforded six or seven sections of strata and other information, that has enabled the general structure of the ground to be made out with greater accuracy than was possible when the old survey was undertaken. These measures, which have a thickness of about 1,000 feet, consist of an alternating series of sandstones and shales, with several beds of ironstone and seams of coal and fireclay, and near the top one or two beds of limestone. At the base there is a bed of coarse false-bedded ferruginous sandstone, with quartz pebbles, which rests unconformably on the Stockingford shales. This sandstone, which was first pointed out ' by Mr. Strahan, is of a buff or yellow colour, and so soft as to be readily used as a building sand. It is of great assistance in tracing the junction between the Cambrian and Carboniferous formations across the country, the white quartz pebbles being very conspicuous, and at once arresting the attention where this junction might be over- looked. This rock is best seen along the lane and in some old quarries on the east side of the Monk's Park Wood, where the unconformity is very marked, the sandstone, which is nearly flat resting on the Cambrian shales, dipping at an angle of 38°. It 16 CARBONIFEROUS. may be followed across the wood to the north side, where there is a small quarry in it. After crossing Merevale Park it makes a good feature as far as Waste Hill, where it comes against the boundary fault, but appears to be continued as a less coarse, but thicker, sandstone nearly as far as Suckle Green. The Coal-measures lie in a flatfish synchnal trough or basin, having its longer axis in a north and south direction, which turns up rather rapidly as it approaches the western, northern, and eastern margins. It was formerly supposed that, in the extreme northern part of the coalfield, about Shuttington, the workable seams of coal would be found at some considerable depth; recent workings, however, at Tamworth Colliery have sho-ftTi that this is not the case, but that the beds turn up some- what rapidly as they approach the large boundary fault, the Seven-feet coal not being more than 70 yards deep on the north side of the road to Polesworth, while it is 170 yards deep at the Colliery. The southerly dip seen in the lane to Shuttington also shows that the beds are rising towards the village. The thicker seams of coal are all in the lower part of the series, and comprise about a dozen seams that have received names, besides several thinner beds of coal. Since the number of pit sections has been increased it has become easier to correlate the various seams than was formerly the case ; but it is still probable that some of them which have received distinct names at different collieries are really the same beds. Mr. Howell, in his description of this coalfield, gives a compara- tive section showing the splitting up of the coalseams and the increase in the thickness of the measures between Hawkesbury Colliery in the extreme south of the coalfield and Stratford Pit on Baxterley Common in this map.* The same thickening of the measures takes place, although m a less degree, further to the north-west, as is shown by the accompanying section. The principal seams in this part of the coalfield are the Four- feet, Eider, Bare, Slate, Seven-feet, and Bench, all of which have in old times been worked either in shallow pits or at the outcrop ; but at the present time the Seven-feet coal is the seam princi- pally worked at the collieries. The Bench coal is said to be inferior throughout the greater part of the district. The fireclays associated with these coals are not used at any of the pits in the map, but further west at Amington and Glascote the clay under the Seven-feet coal is mixed with another clay, and used for fire- bricks. At Dordon clays higher in the series are used. It is in the measures immediately above the Four-feet coal that the principal beds of sandstone are met with. They consist of irregular masses which as a whole can be readily traced across the country, although the separate bcd^ frequently thin out in short distances. Tliey form the abrupt edge that runs from Merevale to Polesworth, and along which they have been quarried at a few places. * Memoirs of the Geological Survey. The Warwickshire Coalfield, p. 10. Fig, 2, Comparative Section of Coal Seams in the extreme north of the Warwickshire POOLEY halu BIRCH COPPICE BIRCH COPPICE NSi HALL END SPEEDWELL FT- //V__ __ -:i "=- ' STRATFORD FOUR FTCOAL RIDER COAL BARE COAL SLATE COAL SEVEN FT COAL .- ELLCOAL 46 STONE COAL FT- IN. - n :3 »— , S.4 e- 3 7- 09 2 e SMITHY COAL O 9 2 3==.— u 0"4 £9 2.6 60~ rr-ifi 2 3-8 2-6 03 1-4 2 3=s 3-1 =1 to a ',1 3-». 3.e 2-9*- — __ 120 Li_ \/ERTICAL SCALE. 60 - - _ 120 I I I I I I I 1 ^1. 1 Her------ r:;i 240 /^cer 2.2 2.3 = ■?.i- 3-6 3.4 0-9 BEMCH COAlH^'o ■ill '6 o I I- HORIZONTAL SCALE I 2 3 MILES -I 4ilO 3288. COAL atEASTJRES. ir The following depths of the Coal at the different pits through- out the district will help to show the general position of the seams :- Four-feet Rider Seven-feet Bench Coal. Coal. Coal. Coal. Yards. Yards. Yards. Yards. Stratford Pit 231 2.50 308 Waste Lane, 200 yds. from south corner of Grendon Wood - . — 90(?) Baddesley Common, 150 yds. south-east of the Red Lion Inn 50 Baddesley Church 60(1) Well just outside north end of Grendon Wood 40 Old shaft, 400 yds. west of Church - 200 Speedwell Pit old Grave Yard Pit 140 163 234 110 Snibson's Wood 30 White House 60 170 Bassett's Bridge, Polesworth — 110 170 Butt Lane, 4.50 yds. south of Polesworth Station 100 Pit at aide of railway south-east of Polesworth Station 60 Birch Coppice Colliery (shaft at Hall End) 173 209 270 Birch Coppice Colliery (shaft at Birch Moor) - . - 159 200 265 Pooley Hall Colliery Tamworth Colliery 71 — 1.55 170 185 218 1,000 yds. north-east of Tam- worth Colliery — — 65-80 The outcrop of these seams can be readily followed by the lines of old workings along the slope of the hill from Mere- vale to Polesworth, although in some cases it is rather doubtful what seams were worked in certain pits. In Monk's Park Wood indications of two coal seams are seen in the stream at the old ponds, and the outcrop may be traced by the lines of old pits to the northern corner, where one of the upper beds is seen in the ditch by the sido of the wood. Mr. Howell states that " At Monk's Park the Seven-feet, the Slate, and Rider coals were wrought formerly to a depth of nine yards, and another coal called the ' Smithy ' was also wrought to the same depth. Ironstone was also raised at the same place, and smelted by charcoal ; but what particular bands were used is not stated, though they were probably from under the Seven-feet coal, where they occur in large balls, as shown in Vertical Section No. 6, Sheet 2L"* The slag heaps ti-om these old furnaces may be seen near where the old ponds were in the lower part of the wood. In the road on the north side of the wood there are several indications of coal, and also across Merevale, one or other of the seams being seen in several places. At Colliery Farm the workings * Loc. <:it. p. 17. 3288. 18 CARBONIFEROUS. to the Seven-feet coal are very apparent, as well as those to some of the higher beds. In Grendon Wood there are a large number of old pits, especially to the Seven-feet coal ; but the outcrop of the higher beds, which leaves the wood and crosses the northern side of the village of Baddesley Ensor, is not quite so clear. North of this the Seven-feet and Bench coals outcrop in Baddesley Wood ; and there arc indications of the higher beds in the fields above and about Snibson's Cottage, In the valley of the Penmire Brook there is an east and Avest fault running nearly along the line of the Watling Street, which has been proved in the Birch Coppice Colliery to have a downthrow to the north of tAventy-five yards. This fault must shift the outcrop of the coal seams some- what to the east, but on account of the high westerly dip its effect is not very marked. In Birch Coppice old coal pits are again very frequent, but to which seams some of them were sunk is not very clear. North of this wood the double seam, known as the Rider and Bare coal, is stated by Mr. Howell to die out. He says, " As the workings here have been some time abandoned I could not obtain any very accurate information as to the exact point where the Rider and Bare coal disappeared, or the way in which this ' double coal ' terminated ; but as far as I could make out from the description given me of the last workings by Mr. Scarrot, of Polesworth, there was no large fault, using that term in its correct sense, but the place of the coal seems to have been taken by a bed of fireclay ; and according to the accounts I obtained from the old miners, the coal terminates quite abruptly, the strata, however, not being shifted up or down. That it was not a slip fault was proved by the other coals, both above and below, being found to contiime further north without any inter- ruption."* At Dordon Brickyard the following thin coals are seen : — ft. in. Sandstone several feet. Dicey coal 1 4 Measures 20 Coal 10 Measures 4 Coal 4 Measures 2 Smut ^Measures 1 The beds dip at an angle of 15° to the west, but they are said to turn over and to be found again on the east side ; so that it is probablethat the thicker seam is the Four-feet coal, which out- crops a little lower down. Between here and Polesworth nearly all the seams appear to have been worked at the outcrop, but there is not much evidence for identifying the different beds. In the railway cutting south of Polesworth Station two seams of coal 4ft. or more in thickness are to be seen. The identity of these coals is now much obscured, but probabljr was much clearer at the time the following statement was written : — " The Four-feet, Slate * Loc. cit. p. 1.5. COAL MEASUEKS. 19 and Seven-feet coals crop out in the railway cutting between Polesworth Station and the bridge, and the Bench coal on the south-east side of the bridge. The measures are much broken and disturbed where exposed in this cutting, and have a general dip to the west at an angle of 45° to 50°, and the unusually high angle at which the strata are inclined is accounted for by the close proximity of the boundary fault, which here runs along the east side of the railway." * We feel rather sceptical as to the absence of the Rider coal and the great thickness (7ft. Sin.) given for the Slate coal about Polesworth. At Pooley Hall Colliery, which is only just on the other side of the river, the section of the different coal seams does not at all correspond with that of the old Polesworth Colliery.+ We, therefore, cannot help thinking that in this latter pit the seams were wrongly identified. It is difficult to correlate the several seams in these two sections ; but if the seam at the bottom of the old Polesworth shaft is taken as the Double Coal, the Slate Coal (7ft. 3in.) would be the Seven-feet Coal of other collieries ; and the character of the intervening measures seems to correspond better on this hypothesis. Again, it is very doubtful if the Rider Coal really dies out altogether, as stated by Mr. Howell. This coal is worked at Birch Coppice, and is 2ft. 6in. thick in the old shaft on Birch Moor, which is a good deal north of where it is said to die out. The measures in the colliery sections north of this have altered so much that at present, it is impossible to correlate these thin seams ; but probably there will be further evidence on this point when the rest of the coalfield is surveyed. To the east of Polesworth and Dordoii the Coal-measures roll over and dip to the east into the great boundary fault, so that the outcrop of tne different seams is repeated along a strip of ground parallel with the fault between the Anker and the Penmire Brook. There are indications of the lowest of these seams in the lane 170 yards west of St. Helena, and in the ditch 260 yards south of that farm. Other seams are to be seen near St. Helena, in the lane 400 yards west of Dordoii Hall, and in the fields near Hare Parlour. A five-feet seam of coal was met with in the well at St. Helena ; and in the California Pit, which was about 200 yards to the north-east, a coal was reached at fifteen yards. There are also the remains of old coal workings at two or three different horizons in the eastern part of the Hollies. Mr. Howell, in writing of this part of the coalfield, says : " The coal has never been worked to aliy extent on this easterly dip, being much broken and faulted. Attempts were, however, made to work the Seven-feet coal by the side of the lane between Poles- worth and Cordon, and the bed was followed in from the crop for a considerable distance, but was found to be so much * Loc. cit. p. 13. Tne recent widening of the railway shows that the beds are very much disturbed here. Three coal seams crop out between the two bridges, and there are three thin coals a little east of this which may repre- sent the Bench Coal. t Hor. Sections, Sheet 21, No. 4. 3288. B 2 20 CAftBONlFEROtJS. shattered by sniall faults as to be altogether unprofitable. These faults were described to me by Mr. Scarrot, the manager of the colliery at Polesworth, as continually throwing down the coal to the east, sometimes many yards, and all rvmning parallel with the boundary fault of the coalfield. It was in consequence of these numerous dislocations that the working of the coal was abandoned, as it was considered that they would most probably continue till the great boundary fault was reached, which would throw the coal down on the east to an unknowia depth beneath the New Red Sandstone."* In the upper part of the Coal-measures there are apparently two beds of limestone ; we say apparently two beds, because from the outcrop it is not very clear whether this is the same bed repeated by a fault or roll of the strata, or whether there are really two distinct bands. At present no sinking has been made above the higher bed which would at once prove the case.f This limestone has a thickness of about three feet, and contains the small serpula Spirorbis pusillus, Mart. (Sp. carbonarius,M.\xrcla..); it varies m colour from hwS or light grey to a dark slaty blue. It has only been seen in situ in the stream in Monks Park Wood ; but it was met with in a well on Bentley Common, and in the Stratford Pit on Baxterley Common, at both of which places it was about a j'ard thick. Although it is not seen to the north of this its outcrop may be traced by the old workings to it north of Long Wood and Cowper's Grove. At the latter place the feature formed by the outcrop terminates abruptly, and there is not much evidence for it further in the same line of strike. Further south, however, at the base of the sandstone escarpment, the limestone appears to be again in force, having been worked in a line of pits between Ash Spinney and Lower Ridding: Fragments of the rock are again seen around the promontory at Baddesley as far as the plantation at the edge of the map, called the Dumbles, where there are old workings. At first we were inclined to think that the outcrop of limestone at Cowper's Grove was broken by a fault ; but on further considera- tion it seems more probable that there are two bands of limestone along the foot of the escarpment between Baddesley and Baxterley. * Loc. cit. p. 14. + A pit has lately been sunk near Kingsbury Wood, on the other side of the Baddesley promontory, which reached a limestone conglomerate nine feet thick at about fifty yards below the outcrop of the limestone that has been mapped; but the Survey has not been carried far enough yet to show the connection between the two. COAL MEASURES. 21 CHAPTER V. CAHBOl^lFEnOVS— (Continued). Coal Measures — (Continued). THE SOUTHERN PART OF LEICESTERSHIRE COALFIELD. The Leicestershire and South Derbyshire coallield comprises an area of between seventy and eighty square miles, of which only the southern portion comes within the limits of this map. This part of the coalfield is divisible into two areas; the Eastern or Coleorton coalfield, and the Western or Moira coal- field. These are separated from each other by an anticlinal arch of lower unproductive measures, containing only a fbw thin seams of coal, which rise up fiom below, and come to the surface near Normanton, Packington, and Ashby. One of thjese coal seams is seen in the railway cutting at Breach Hill : and there are indications of two or three other seams to the north of Nor- manton. On the west, side, close to the Boothorpe Fault, there- are two or three seams seen in the railway cutting north of Willesley Wood, one of which is probably the representative of the Rafferee coal that crops out at Woodville, and will be further referred to in the description of that country. These measures dip to the east on the east side of Ashby and Packington, and to the west on the west side of these places, which are nearly on the Une of axis. Mr. Coleman states that their thickness is at least 1,000 feet, but what was the evidence upon which this statement was based we do not know.* Coalville District. The eastern or Coalville portion of the coalfield is almost entirely concealed by the overlying Triassic rocks, so that it is only over a small area at Heather and along the bank below Alton Grange that the Coal-measures come to the surface, and are shown by colour on the map. They have, however, been proved by collieries and borings to extend as far south as a line drawn from Heather to Desford, and may be found a little beyond this, but it is not likely that they extend very much further, as borings in the neighbourhood of Market Bosworth have proved the absence of Coal-measures : neither do they extend east of a line drawn from Whitwick through Thornton to near Desford. This ^area is bounded on the west by the outcrop along the bank running from Alton Grange southwards, although beyond Normanton it is completely masked by the overlying Trias. On * Kev. W. H. Coleman in White's Histoiy of Leicestershire. Ed. 2, p. 92, 1863, 22 CARB0NIFER6US ^ to o I □ 2° ^. I J. fe fl t^J > 3) *\ "Ji o Jt o - c "^ H ■»i ^8. il" S 3S- to -J 1 2-. ^1 * ^ o N X-O S-+* t s (0 o 'J o , ^ w -w o c (t UjO ^9 ■ -1* o - o- COAL MEASURES. 23 the east the boundary is formed by the large fault which lirings up the Clharnwood rocks, and against which the Coal-measures turn up at a sharp angle. This fault has been proved in the Whitwick Colliery to run from the western side of the village of Whitwick to Broom Leys, and it is probably continued by Bardon Hill Station to Thornton and the eastern side of Desford. This portion of the coalfield contains about eight workable seams of coal, varying in thickness from three to nine feet. Some of the higher seams have been worked at Bagworth, Ibstock, and elsewhere in old times; but the principal seams now used are the Upper Main or Coleorton Coal and tJie Lower Main or Roaster Coal. The general dip of the beds is to the east at about 4°, they are therefore deepest about Ellistown and Bagworth, and crop out to the west beneath the New Red Sandstone ; so that the higher seams, which occur in these shafts, are absent in those of Nailstone and Ibstock, while at Heather only the lowest seams are present. Over the Cloal-measures to the south of Whitwick there is a sheet of dolerite*, which has been ejected in a molten state from the line of the boundary fault, and run over them probably before the Triassic rocks were deposited, as where the rock is found in contact with the coal seams the latter are burnt to cinders, while the sandstone above does not appear to have been subjected to heat. This rock is 81 feet thick in the eastern shaft (Xo. 6) of Whit- wick Colliery, but thins out towards the north-west and south, being absent in the Snibston Pits (Nos. 2 and 3), as well as tlioso at Ibstock, Nailstone, and Bagworth, but occurs at South Leicestershire and Ellistown. Its general extent and thickness may be gathered from the diagram given on the following page. Moira District. The western or Moira portion of the coalfield occupies a large part of the north-west quarter of the map. The Coal-measures over this area are much more exposed than in the CoalyiUe district ; and it is only along the western and southern portions that they are covered by Trias. The strata in general dip to the west, but along the western and southern margins they turn up, as well as to the north beyond the limits of the map ; they there- fore form an irregular basin, of which the deepest part is about Moira. On the east they are cut off by the great Boothorpo Fault, which brings up the unproductive measures of the Ashby district. These Coal-measures have been proved to a depth of over 1,600 feet ; they contain many valuable seams of coal, the details of which will be given in the special memoir on the coalfield. A general idea, however, of the seams and the thicknesses of the intervening measures may be gathered from the following table : — * See S. Allport, Geol. Mag., vol. vii., pp. 159 and 4.35, 1870, and Quart. .Toiirn. Geol. Soc, vol. xxx., p. 510, 1874; also .J. J. H, Teall, British Petrography, p. 211, 1888. 24 CAEBONIFEROUS. Fig., 4., Plan of the East Leicestershire Coalfield,' showing supposed extent of the Whinstone SNIBSTOM hl^3 o inUtirifk .^-'\ 5MiG0-0 SNIBSTON NQS ,--' A/oe WHITlViCK COLLIERY ° iT ° o [ 21 9 N A \ iBSTOCK COLLIERY O Hard on. Hiil Hu^tfl-t^co fC' \BarcUtn7fiU Station. SOUTH LEICESTERSHIRE 12 is-oOOia 4, 1-^ ELLISTOWN 25 8 COLLIERY i^. 15 A S/CL/Tfon J-uuicr ^ NAIL5T0NE i O COLLIERY BACWORTH O COLLIERY Bacfworth.