i “ee | : f . ihe Se a WAN! fi IN Wh SU Gua ala) saps i RSTRNT Ch SOP TAIT SKEET! ie te a | i} j | ES PATE BURNDY LIBRARY Chartered in 1941 GIFT OF BERN DIBNER The Dibner Library of the History of Science and Technology SMITHSONIAN INSTITUTION LIBRARIES “iss ro ae SNe A si DI: THE SILURIAN SYSTEM, FOUNDED ON GEOLOGICAL RESEARCHES IN THE COUNTIES OF SALOP, HEREFORD, RADNOR, MONTGOMERY, CAERMARTHEN, BRECON, PEMBROKE, MONMOUTH, GLOUCESTER, WORCESTER, AND STAFFORD; WITH DESCRIPTIONS OF THE COAL-FIELDS AND OVERLYING FORMATIONS. BY RODERICK IMPEY MURCHISON, F.R.S. F.L.S.— VICE-PRESIDENT OF THE GEOLOGICAL SOCIETY OF LONDON, GENERAL SEC. BRIT. ASSOC. ADVANCEMENT OF SCIENCE, MEMBER OF THE ROYAL GEOGRAPHICAL SOCIETY, HON. MEM. OF THE ROYAL IRISH ACADEMY, ETC. ETC. ETC. IN TWO. PARTS, PAC ae 1. | LONDON: JOHN MURRAY, ALBEMARLE STRERT. . 1839. RED LION COURT, FLEET STREET. 2 TO THE REV. ADAM SEDGWICK, F.R.S., V.P.G.S. WOODWARDIAN PROFESSOR, CAMBRIDGE, ETC. To you, my dear Sedgwick, a large portion of whose hfe has been devoted to the arduous study of the older British rocks, I dedicate this work. Having explored with you many a tract, both at home and abroad, T beg you to accept this offering as a memorial of friendship, and of’ the high sense I entertain of the value of your labours. Yours most sincerely, RODERICK IMPEY MURCHISON. Bie i avrht .S0d! HOM AD sabe acne 7 SO awe & ‘his : eo Re Fes SAVOENE CSG: ‘Sule aM Elia PREFACE. HAVING discovered that the Region formerly inhabited by the Silures, celebrated in our annals for the defence of the great Caractacus, contained a vast and regular succession of undescribed deposits of a remote age, I have named them the “ Silurian System?’’. The Introductory Chapter details the state of the subject when this m- quiry commenced, the origin and progress of the work, and the objects to be attained by its completion. The first part, embracing descriptive geology, concludes with a review of the most striking phenomena of the ancient epochs which I seek to illustrate; the second describes the fossil animals which are imbedded in the strata. The map, coloured sections, and numerous wood-cuts, mark 1 See a notice of the ancient topography of the Silurian Region, p. xxxi. Vi PREFACE. the subdivisions of the surface -and the structure of the sub-soil; while the fossil animals are figured in separate plates. Finally, lest some of my readers should imagine, that he whose proper study is the frame-work of the earth, is indifferent to the beauties of its outline, I beg to offer a few pictorial sketches of this fine region, alike eulo- gized by the poet for its fertility and the valour of its people—and which the wayfaring geologist can truly say is a land of real kindness and hospi- tality : “ Where from Silurian vats high sparkling wines Foam in transparent floods.” “ Tn ancient days The Roman legions and great Czesar found. Our fathers no mean foes, and Cressy plains And Agincourt, deep tinged with blood, confess What the Silures’ vigour unwithstood Could do in rigid fight.” London, November 29, 1838, LIST OF SUBSCRIBERS. ACKLAND, Sir Thomas Dyke, Bart. M.P., F.R.S., F.G.S., Devonshire. Adams, John, Esq., Holyland, Pembroke. Adare, Viscount, M.P., Royal Irish Academy, Dublin. Addenbrook, Henry, Esq., Broom, near Stourbridge. Allen, John H., Esq., Cressilly, Narbeth. Allen, L. B., Esq., Cilrhiw, Narbeth. Amherst, Earl, 66, Grosvenor Street. Andrews, Evan, Esq., B.A., Llandilo. Antrobus, Sir Edmund, Bart., 146, Piccadilly. Atcherley, Mr. Sergeant, Marton, Shropshire. Austen, W., Esq., F.G.S., Ogwell Park, Newton Abbots, Devon. Aylmer, G. W., Esq., F.G.S., 47, Upper Grosvenor Street. Bailey, Joseph, Esq. jun., Nantygl6, Monmouthshire. Bailey, W. W., Esq., (at Mr. Hutton’s, 5, Jeffries Square, _ City) Kilburne, near Derby. Baillie, David, Esq., F.R.S., 4, Audley Square. Bailliére, M., Foreign Bookseller, (4 copies). Barker, John, Esq., Wolverhampton. Baker, Thomas John Lloyd, Esq., Hardwicke Court, Gloucestershire. Banks, Richard, Esq., Kington. Barneby, John, Esq., M.P., Brockhampton, Worcester. Bateman, Lord, Shobden Court, Leominster. Bathurst, Rey. W. R., M.A., Barwick-in-Elmret. Bathurst, Charles, Esq., Lidney Park, Gloucestershire. Beaumont, M. Elie de, Membre de l'Institit., For. Mem. _&.S. and G.S. Lond., Paris. Bennett, George, Esq., Maisonette, Dudley. Bent, John, Esq., Liverpool. Berry, Richard Sparling, Esq., Bolton Lodge, Lancaster. Best, B., Esq., Corngreaves, Birmingham. Biddulph, John, Esq., 14, New Street, Spring Gardens, and Ledbury. Biddulph, Rev. J., Amroth Castle, Tenby. Bilton, Rey. William, 7, Connaught Place West. Birmingham Library. Bishop, ‘Thomas, Esq., Llandovery. Black and Armstrong, Messrs., (2 copies). Blake, W., Esq., F.R.S., F.G.S., 62, Portland Place. Boase, C. W., Esq., M.G.S.C., Dundee. Bodley, Thomas, Esq., F.G.S., &c., Brunswick Terrace, Brighton. Bombay Library, (Longman and Co.). Bonnor, John, Esq., Bryn-y-Gwallia, Oswestry. Booker, Thomas William, Esq., Velindre, Cardiff. Booth, Thomas W., Esq., Felindre, Cardiff. Botfield, Thomas, Esq., F.R.S., F.G.S., Hopton Court, Cleobury. Botfield, Beriah, Esq., ditto. Botfield, W., Esq., Deckar Hill, Shiffnall. Boughton, Sir W. E. Rouse, Bart., F.R.S., Downton Hall, Ludlow. Bowen, John, M.D., Caermarthen. Bowman, J. E., Esq., Gresford, Wrexham. Boyles, Mrs., Buriton, Petersfield. Braybrooke, Lord, 10, New Burlington Street. Bridgewater, Countess of, Ashridge, Hemel Hempstead. Bright, Benjamin Heywood, Esq., F.G.S., &c., Stone Buildings, Lincoln’s Inn. Bright, Richard, Esq., Ham Green, near Bristol. Brigstock, Mrs., Combe Hay, Bath. Bristol, Literary and Philosophical Institution of, Bristol. Broderip, W. J., Esq., F.R.S., F.G.8., 2, Raymond's Buildings, Gray’s Inn. Brougham, Lord, F.R.S., Eaton Street. Brydges, Sir Harford Jones, Bart., Boultibrooke, Pres- teign. Buckland, Rev. W., D.D., V.P.G.S., F.R.S., Christ- church, Oxford. Buddle, William, Esq., F.G.S., Newcastle-on-Tyne. Bullock, Charles, Esq., Woodville House, Bideford, Devon, (per Mr. Wix). vill Burd, T., Esq., Cardiston, Salop. Burlington, the Earl of, F.R.S., F.G.S., 10, Belgrave Square. Caledon, the Earl of, F.G.S., 5, Carlton Terrace. Cautley, Capt., Bengal Artillery, (Messrs. Smith and Elder). Carlisle, the Very Rev. the Dean of, F.G.S., &c., Gros- venor Street. Cartwright, W. H., Esq., Dudley. Cawdor, the Earl of, F.G.S., 74, Audley Bere London, (2 copies). Charlton, W., Esq., Apley Castle, Salop. Chantrey, Sir Francis, R.A., F.R.S., F.G.S., 62, Bel- grave Place, Pimlico. Cheese, Edmund, Esq., Kington. Chichester, the Bishop of, F.R.S., F.G.S. Childe, W. Lacon, Esq., Kinlet, Bewdley ; London. Clarke, Rev. W. B., Stanley Green, Poole. Cludd, Edward, Esq., Orleton, Salop. Clerke, Major, F.R.S., F.G.S., 9, Trevor Terrace, Knightsbridge. Cleveland, Duke of, we James’s Square, London, (4 copies). Clive, Viscount, M.P., Powis Castle, Hill Street. Clive, Lady Lucy, Powis Castle. Clive, the Hon. R. H., M.P., Oakley Park, Ludlow; 53, Grosvenor Street. Clive, Lady Harriet, Oakley Park, Ludlow. Clive, the Rev. W., Welch Pool. Clive, Lieut-Col., Whitfield, Hereford ; 18, Grafton Street. Cockburn, Sir Wm. Sarsfield, Bart., Downton, Radnor. Cole, Viscount, M.P., F.R.S., F.G.S., Florence Court, Fermanagh. Collins, Henry, Esq., Inner Temple, (per Mr. Nattali). Conybeare, Rev. W., F.R.S., F.G.S., Axminster. Cooke, Rev. Dr., F.G.S., Tortworth, Gloucester. Corbet, the Rev. Waties, Le Botwood, Shrewsbury. Corbet, Panton, Esq., Leighton Hall, Welch Pool. Cornwall, Royal Geological Society of, Penzance. Corrie, Mrs. Woodville, Birmingham. Cotes, John, Esq., Woodcote, Shiffnal. Cotterell, Sir John G., Bart., Garnons, Hereford. Craven, the Earl of, Charles Street, Berkeley Square. Crichton, Sir Alexander, M.D., F.R.S., F.G.S., Hanover Square. Crump, Thomas, Esq., Chorley, Bridgnorth. Cumming, John, Esq., Albany, Piccadilly. Cunningham, R. G. H., Esq., M.W.S., Edinburgh, (per Longman and Co.). Currer, Miss Richardson, Eshton Hall, near Gargrave, Yorkshire. LIST OF SUBSCRIBERS. Darlington, the Earl of, Upper Brook Street. Dartmouth, Earl of, 1, St. James’s Square, (2 copies). Darwin, Charles, Esq., F.R.S., Sec. G.S., 36, Great Marlborough Street. Davies, David, Esq., Froodvale, Llandovery. Davies, James, Esq., Moor Court, Kington. Davies, James, Esq., Ludlow. Davis, Dr., Presteign. Dawson, R., Esq., Sandwell Cottage, Birmingham. Deane, Rey. Thomas, Colwall, Herefordshire. De la Beche, Henry Thomas, Esq., F.R.S., F.G.S., Ord- nance Geologist. Dillwyn, J. L., Esq., F.R.S., F.G.S., Swansea. Dod, J. W., Esq., Cloverley Hall, Salop. Donkin, Armorer, Esq., Newcastle-on-Tyne. Donne, Dr., Oswestry. Donne, Rey. Stephen, Oswestry. Douglas, James, Esq., (Longman and Co.). Downing, Francis, Esq., The Priory, Dudley. Dudley Library. Dudley, John, Esq., Tiled House, King’s Swinford, Dudley. Du Gard, Thomas, M.D., F.G.S., Shrewsbury. Dukinfield, the Rev. Sir Henry, Bart., 6, St. Martin’s Place. Dumont, M. de, Liége, (by Black and Amnsevone), Dunlop, James, M.D., Wanda Club, St. James’s Square. Duppa, F. B., Esq., 1, Lincoln’s Inn, New Square. Durham, the Bishop of, (2 copies). Dynevor, Lord, Dover Street, London. Eaton, Lieut. J., R.N., _Vale Cottage, Sandwell, Bir- mingham. Eastnor, Viscount, M.P., 33, Dover Street. English, Henry, Esq., F.G.S., Gough Square. Egerton, Sir Philip de Grey, Bart., M. es FOR EGrs Oulton Park, Cheshire. Evans, —, Esq., Hon. Sec. Natural History Society, Worcester. Evans, Rev. William Edward, Burton Court, near Leo- minster. Evans, John, Esq., 32, Hertford Street, May Fair. Eyton, Thomas, Esq., Eyton, Wellington, Salop. Ferguson, Robert, Esq., M.P., F.R.S., F.G.S., Portman Square. Ferguson, Miss, Yatton Court, Aymestry, Leominster. Fetherstonhaugh, Sir Harry, Bart., Up Park, Peters- field. Firnestone, George, Esq., Standhills House, Dudley. Fitton, W. H., M.D., F.R.S., V.P.G.S. LIST OF SUBSCRIBERS. 1X Foley, Edward T., Esq., M.P., Stoke Edith, Hereford. Forbes, John Hopton, Esq., F.G.S., 6, Ely Place. Ford, Richard, Esq., Shrewsbury. Forester, Lord, Willey Park, Salop; 21, Charles Street, Berkeley Square. Gibbons, Benjamin, Esq., Corbyn’s Hall, King’s Swin- ford, Dudley. Gilbert, Davies, Esq., V-P.R.S., F.G.S., &c., East Bourne. Gladstone, John, Esq., Carlton Gardens. Goodhall, H. E., Esq., 22, Guildford Street (deceased). Goodricke, Sir Francis H., Bart., Studley Castle. Gore, W. Ormsby, Esq., M.P., Porkington, Oswestry. Grant, Henry John, Esq., the Gnoll, Neath. Greenough, G. B., Esq., F.R.S., F.G.S., Regent’s Park. Greenly, Lady Coffin, Titley Court, Kington. Greenock, Lord, Major-General, Carlton Terrace, Edin- burgh. Griffith, R., Esq., Pres. Geol. Society of Dublin, Fitz- william Place, Dublin. Guest, Sir J. J., Bart., Dowlais, Glamorganshire. Guillemard, John, Esq., F.R.S., F.G.S., 27, Gower Street. Gurney, Hudson, Esq., F.R.S., V.P.S.A., 9, St. James's Square, (2 copies.) | Gwyn, Howel, Esq., Baglan House, Neath. Gwynne, Alban Thomas Jones, Esq., Monachty, Cardi- ganshire. Hailstone, Samuel, Esq., F.L.S., F.G.S., Horton Hall, Bradford, Yorkshire. Hallam, Henry, Esq., F.R.S., F.G.S, 67, Wimpole Street. Hall, Sir Benjamin, Bart., M.P., 65, Wimpole Street ; Llanover, Abergavenny. Hamilton, the Hon. Frederick, Burwarton, Ludlow, Salop. Hamilton, W. I., Esq., Sec. G.S., Chester Square. Hanson, Joshua Flesher, Esq., Gellywasted, Monmouth- shire. Harcourt, Captain Octavius, R.N., Swinton Park, Masham. Harding, Major, F.G.S., Tiverton, Devon. Hare, Col. R. G., South Street, Grosvenor Square. Harrison, William, Esq., (Mr. Walker, Strand). Hartshorne, Rev. H. C., Cogenhoe Rectory, Northamp- ton. ; Hastings, C., M.D., F.G.S., Worcester. Haycock, Edward, Esq., Priory, Shrewsbury. Hector, Cornthwaite, Esq., M P., Stodham, Petersfield. Herbert, the Hon. Sidney, M.P., Grafton Street. Hereford, the Viscount, Tregoyd, Hay. Hereford, the Bishop of, F.G.S., &c., Palace, Hereford ; 14, King Street, St. James's. Herschel, Sir John F. W., Bart., K.H., F.R.S., F.G.S. Heywood, Thomas, Esq., Hope End, near Ledbury. Hibbert, Dr., F.G.S., Manor Place, Edinburgh. Higgon, James, Esq., Haverfordwest. Hill, General Lord, Belgrave Square. Holbech, John, Esq., per Mr. Rodwell, Bond Street. Holford, Major Gwynne, Buckland, Brecknockshire, and Kilgwynn, Caermarthenshire. Holme, Edward, Esq., M.D., Manchester. Hope, the Rev. W. F., F.R.S., F.G.S., Upper Berkeley Street. Hopkinson, Charles, Esq., Eaton Place. How, W. G., Esq., Shrewsbury. Hudson, Robert, Esq., Clapham Common. Hugonin, Mrs., Nursted House, Petersfield (deceased). Hulton, W., Esq., Hulton Park, Bolton, Lancashire. Humphreys, Henry, Esq., Tanylan, Kidwelly, Caermar- thenshire. Hunter, William Perceval, Esy., R 6, Albany, Picca- dilly. Hurt, Charles, Esq., Wirksworth, Derbyshire. Hutton, R., Esq., M.P., F.G.S., M.R.I.A., Putney Park, Surrey. Hutton, Thomas R., Esq., 5, Jeffries Square, City. Hutton, James, Esq., 5, Jeffries Square, City. Ibbetson, L. L. Boscawen, Esq., F.G.S., Ventnor, Isle of Wight. Johnes, John, Esq., Dolecothi, Llandovery. Johnston, Professor, University, Durham. Johnstone, Sir John V. B., Bart., M.P., F.G.S., Hack- ness, Yorkshire. ; Jones, Rey. John, Hereford. Jones, David, Esq., Jun., banker, Llandovery. Jones, Edward, Esq., Velindre, Llandovery. Jones, John, Esq., Brynbrain, Caermarthenshire. Jones, Captain Husbold, R.N., 30, Charles Street, St. James's. Jones, John, Esq., M.P., Ystrad, Caermarthenshire. Joy, Henry H., Esq., Q. C., Hartham Park, Chippen- ham: 11, Great Queen Street. Kaye, Colonel Wilkinson, Crescent, Bath. Knowles, Sir Francis C., Bart. M.A., F.R.S., Vaynor Park, Welch Pool. Konig, C., Esq., F.R.S., British Museum. Kyrke, James, Esq., Wrexham; care of 'T. Penson, Esq., Oswestry. Kyrke, E., Esq., Glascoed House, Wrexham. b x LIST OF SUBSCRIBERS. Langdale, Lord, Master of the Rolls, F.G.S., 37, South Street. Leach, Henry, Esq., F.G.S., Milford Haven. Leach, Francis Edwards, Esq., Kilybebell Place, Neath. Legh, G. Cornwall, Esq., F.G.S., High Legh, Cheshire. Leigh, Capel Hanbury, Esq., Pontypool Park, Mon- mouthshire. Leighton, Sir Baldwin, Bart., Loton Park, Salop. Lemon, Sir Charles, Bart., M.P., F.R.S., F.G.8., 46, Charles Street, Berkeley Square. Lewis, the Right Hon. Thomas Frankland, M.P., F.G.S., Harpton Court, Radnor; 33, Hertford Street. Lewis, George Cornewall, Esq., F.G.S., 33, Hertford Street. Lewis, James George, Esq., Clee Hill, Ludlow. Lewis, David Jones, Esq., Gilfach, Llandovery. Lewis, Rey. T. T., Aymestry, Leominster. Liddell, Hon. Mrs. H., Northumberland. Liverpool, Earl of, Fife House, London. Liverpool Library, Liverpool. Lloyd, Lieut.-General Sir George, Ferney Hall, Lud- low. Lloyd, Thomas Lewis, Esq., Nantgwillt, Rhayadr. Lloyd, John Arthur, Esq., Leaton Knolls, Salop. Lloyd, Thomas, M.D., Ludlow. Lloyd, George, M.D., Newbold Terrace, Leamington. Lloyd, Rey. Henry Robert, Tanyrallt, Llandovery. Lonsdale, Earl of, Hill Street, Berkeley Square. Lonsdale, W., Esq., F.G.S., Geol. Soc., Somerset House. Lowe, William, Esq., Tanfield Court, Temple. Lyell, Charles, jun., V.P.G.S., F.R.S., 16, Hart Street, Bloomsbury. Lyon, J. Hayes, Esq., Ashfield, -Neston, Cheshire. Lyttelton, Lord, Hagley Park, Stourbridge. Mackenzie, Sir George, Bart., F.R.S.E., F.G.S., Coul, Ross-shire, N. B. Marshall, John, Esq., Halsteads, Penrith, 41, Lower Grosvenor Street. Marshall, T. G., Esq., F.G.S., 41, Lower Grosvenor Street. Marshall, W., Esq., M.P., Patterdale Hall, Penrith. Massie, W. W., Esq., Lansdowne Villa, Cheltenham. Mathews, William, Esq., F.G.S., Green Hill, Dudley. Maurice, B. M. Bonnor, Bryn-y-Gwallia, Oswestry. Meredith, John, Esq., Kington. Mercer, George, Esq., F.G.S., 52, Queen Anne Street. Miller, Professor, F.G.S., St. John’s College, Cam- bridge. Milne, Joseph, Esq., F.R.S.E., Edinburgh, (Longman and Co.) Montgomeryshire Canal Company, Welch Pool. More, R. B., Esq., F.G.S., Linley Hall, Bishop’s Castle. (2 copies.) Morgan, Sir Charles, Bart., Tredegar, Glamorganshire ; Pall Mall. Morgan, Charles, Esq., M.P., ditto, ditto. Morgan, Octavius, Esq., F.R.S., F.G.S., ditto, ditto. Murray, John, Esq., Albemarle Street. Mushet, David, Esq., Coleford. Mynors, Peter Rickards, Esq., Enjob, Radnor. Myton, Henry George, Esq., Cleobury House, Cleobury. Neath Library, Neath. New York State Library. Northampton, the Marquess of, Castle Ashby, North- ampton. Northumberland, Duke of, K.G., F.R.S., F.G.S., North- umberland House. Northumberland, Duchess of. Norwich, Bishop of, P.L.S., F.R.S., F.G.S., 38, Lower Brook Street. Omalius d’Halloy, M.d, Namur, (by Black and Arm- strong.) Ormerod, George, Esq., D.C.L., F.R.S., Tedbury Park, Gloucestershire. Owen, Rear-Admiral Sir E., Windlesham, Surrey. Owen, E. W. Smythe, Esq., Condover Hall, Salop. Owen, Rev. E. B., Wellington, Salop. Owen, Sir John, Bart., M.P., Orielton, Pembrokeshire. Owen, Colonel, M.P., Lianstinaer, Pembrokeshire. Oxmantown, Viscount, F.R.S., F.G.S., Portland Place. Parker, Thomas N., Esq., Sweeney Hall, Oswestry. Parke, J., Rt. Hon. Baron, 56, Park Street. Partridge, Mrs., Bishop’s Wood, near Monmouth. Pearson, Rey. C., Witley, Worcestershire. Peel, Robert, Esq., Taliaris, Caermarthenshire. Pemberton, the Rev. R. M., Church Stretton, Salop. Penson, Thomas, Esq., Oswestry. Pendarves, J. E., Esq., M.P., F.G.S.; 36, Eaton Place. Penfold, Miss, Cheam, Surrey. *Peploe, Samuel, Esq., Garnstone Park, Hereford. Philip, Thomas, Esq., Ynys, Angharad, Newbridge, Glamorganshire, (2 copies.) Philipps, John Walters, Esq., Aberglasney, Caermar- thenshire. Phillips, Sir R., Bart., M.P., Picton Castle, Haverford- west. Phillips, John, Esq., Williamston, Haverfordwest. Phillips, Professor, F.R.S., F.G.S., York. Portlock, Captain, R.E., F.G.S., M.R.L.A., Ordnance Survey, Ireland. LIST OF SUBSCRIBERS. x1 Powell, Edward, Esq., Rose Bank, Hagley, Stour- bridge. Powis, Earl of, Berkeley Square, and Walcot Park, (10 copies. ) Price, Sir Robert, Bart., M.P., Foxley, Hereford. Price; Richard, Esq., M.P., Norton, Presteign. Price, R. W., Esq., Williamsfield, Llandovery. Protheroe, Edward, Esq., M.P., Newnham, Gloucester- shire. Prudhoe, Lord, F.R.S., Stanwick Park, Northumber- land House. Pryce, Rev. Mostyn, Greenley, Welch Pool. Pugh, W., Esq., Bryn Llowarch, Newtown, Montgo- meryshire. Pugh, David, Esq., Llanerchydol, Welch Pool. Rees, Rev. Professor, St. David’s College, Lampeter. Rees, William, Esq., Llandovery. Rees, Rev. William Jenkins, M.A., Cascott Rectory, Presteign. Rennie, Sir John, F.R.S., F.G.S., Whitehall Place. Rich, Mr., Foreign Bookseller, 12, Red Lion Square, (3 copies). Roberton, Dr., Geol. Soe. of France, Paris. Roch, George, Esq., Butter Hill, Haverfordwest. Rocke, Rev. John, Clungunford, Ludlow. Rodney, the Hon. Harley, Berrington, Leominster. Rogers, Edward, Esq., Stanage Park, Ludlow. Royle, J. Forbes, M.D., F.R.S., Sec. G. S. (Messrs. Par- bury and Allen). Sabine, Major, R.A., F.R.S., Tortington, Arundel. Salt, Thomas, Esq., Salop. Salwey, Humphrey, Esq., Ludlow. Sanders, William, Esq., Bristol. Seales, H., Esq.. Aberdare, Glamorganshire, (2 copies). Scholes, Thomas Siddons, Esq., High Bank, near Man- chester. Scudamore, J. Lucy, Esq., Kentchurch, Hereford. Sedgwick, Rev. Professor, V.P.G.S., F.R.S., &c., Cam- bridge. Severne, J. M., Esq., Wallop Hall, Shrewsbury. Shepherd, Lady Mary, 25, Henrietta Street, Cavendish Square. Shrewsbury Subscription Library, Shrewsbury. Shropshire and North Wales Natural History and An- tiquarian Society, Shrewsbury. Slaney, R. A., Esq., M.P., Shrewsbury. Smith, Rev. J. Pye, D.D., LL.D., F.G.S., Prof. Div. Dissenting College, Homerton. Smith, J., Esq., F.G.S., Jordan Hill, near Glasgow. Snow, B. G., Esq., F.G.S., Highgate, Solly, William, Esq., Haverfordwest. Solly, Henry, Esq., Llampeter, Cardiganshire. Somers, Earl, Eastnor Castle, Ledbury. Sopwith, Thomas, Esq., Neweastle-on-Tyne. Stackhouse, Mrs. Acton Scott, Church Stretton. Stanger, William, M.D., F.G.S., M.W.S., Wisbeach, (Smallfield and Son, 69, Newgate Street). Stanton, Thomas, Esq., Ellesmere. St. Asaph, the Very Rey. the Dean of, Cradley Rectory, Worcester. Stevenson, P. Robert, Esq., Civil Engineer, Great George Street (2 copies). Stoke, Rev. Oswald Leicester, Market Drayton. Stokes, Rev. J. C. H., Maunden Vicarage, Bishop Stortford. Strickland, Hugh E., Esq., Cracombe House, Evesham, Worcestershire. Stutchbury, S., Esq., Institution, Bristol. Sunter, Mr. R., York. Sussex Royal Scientific Institution, 20, Steyne, Brighton. Sutherland, Duke of, Stafford House (2 copies). Sutherland, the Duchess Countess of, Hamilton Place ; Dunrobin Castle. Swainson, E. C., Esq., 12, South Crescent, Bedford Square, London. Swanwick, Dr., Macclesfield. Sykes, Rev. Christopher, Rooss, near Hull. Sykes, Lieut.-Col. W. H., F.R.S., 47, Albion Street, Hyde Park. Talbot, Earl, Ingestrie, Litchfield. Tardrew, Samuel, Esq., Caermarthen. Taunton, W. P., Esq., F.G.S., near Bristol. Taylor, James, Esq., Moore Green, Birmingham. Taylor, John, Esq., F.R.S., Treas.G.S., 12, Bedford Row. Taylor, Richard, Esq., F.G.S., Under Secretary of the Linnean Society, Red Lion Court, Fleet Street. Taylor, Miss, Moseley Hall, Birmingham. Telford, Thomas, Esq., Abingdon Street, Westminster. Tennant, William, Esq., Kemp Town, Brighton. Thomas, Thomas Edwards, Esq., Llangadock, Llando- very. Thomson, James, Esq., F.R.S., Primrose, near Clitheroe. Traherne, Rey. J. M., Coedriglan, Cardiff. Trevelyan, Wm. Calverley, Esq., F.G.S., Wallingford, Northumberland. Trevor, the Hon, G. R. Rice, M.P., 10, Stratton Street. Troost, Professor, of Nashville, Tennessee, United States. Trotter, Alexander, Esq., F.G.S., 17, Orchard Street, Portman Square. Twemlow, Thomas, Esq., Peat’s Wood House, Drayton. Tyndale, J., Esq., Sackville Street. b 2 Xil LIST OF SUBSCRIBERS. Tyrconnel, the Earl of, F.G.S., Kiplin, Catterick. Vaughan, Colonel, Woodstone, Peterborough. Verneuil, M. de, Société Géologique de France, Paris. Vickers, Rev. W., Chetton, Bridgnorth (to Messrs. Ri- vington’s). Vivian, J. H., Esq., M.P., F.G.S., St. James’s Place. Vyvyan, Sir Richard, Bart., F.R.S., F.G.S. Warlow, J., Esq., Surgeon, Haverfordwest. Warburton, Henry, Esq., M.P., F.R.S. F.G.S., 45, Cadogan Place. . Ward, William, Esq., George Street, Wolverhampton. Walker, Joseph N., Esq., Calderstone House, Liverpool. Washington, Capt., R.N., Sec. Royal Geogr. Society, 21, Regent Street. Watt, James, Esq., F.R.S., Aston Hall, Birmingham. Wheldon, Thomas, Esq., Barnard Castle. Whewell, Rev. W., P.G.S., F.R.S., Trinity College, Cambridge. Whitby, Mrs., Newlands, Lymington. White, R. M., Esq., Linley Hall, Bishop’s Castle. Whitmore, W. Woolryche, Esq., Dudmaston House, Bridgnorth ; 1, Dorset Street. Whittaker, John, Esq., Newcastle Court, Radnorshire. Wilkins, J. P., Esq., Maesderwen, Breconshire. Williams, John, Esq., Pitmarston, near Worcester. Williams, Penry, Esq., Penpont, Brecon. Williams, Sir James, Bart., M.P., Edwinsford, Caermar- thenshire. Williams, Walter, Esq. Albion Iron Works, West Bromwich, Birmingham. Williams, William, Esq., Surgeon, Llandovery. Wilson, John, Esq., Seacroft Hall, Leeds. Wingfield, Colonel, F.G.S., Onslow, Salop. Winnington, Sir Thomas, Bart., M.P., Stanford, near Worcester. Witham, H. Maire, Esq., F.G.S., Lartington Hall, near Barnard Castle. Woodhouse, John, Esq., F.G.S., Ashby de la Zouch. Worcestershire Natural History Society. Wright, Smith, Esq., Rempston Hall, Loughborough. Wynn, Sir Watkin Williams, Bart., M.P., St. James’s Square, London. Yates, James, Esq., M.A., F.G.S., 49, Upper Bedford Place. . ERRATUM. | For Philip, Thonias, Esq., read Thomas, Philip, Esq., Ynys Angharad, Glamorganshire. CONTENTS. Page List of Illustrations ..... dame ah SSP e oheeyer Wel eter eae eS CAL cs ar racine ne REDO EE Saad xxi Description of Map..........6.. Pe elem tec aR ee teehee ae Ee A nee ORV El Notice of the ancient Topography of the Silurian Region...........5+.+. oF safc a te eco eee CHAPTER TI. INTRODUCTION. Design of the work.—Previous state of geological knowledge.—Order of the older fossiliferous strata.— Interval to be filled up, between the secondary deposits previously described, and the older slaty rocks.—Origin of this inquiry, and method pursued in following it out.—General view of the oldest LOS SIMGLOUSEC CMOSIC Seen oer res MEERA aoe vise charm RG Ne UiRue 54MM cas) ensis Sab Gio AP ce nyt Oe egaere lie egciter als 3 CHAPTER II. OOLITIC SYSTEM. Inferior Oolite.—Lias.—Outliers of Lias (PI. 29. figs. 1, 2,3.) ........ 0. cece eee ee ee eee ee eereee 18 CHAPTER III. NEW RED SYSTEM. UPPER FORMATIONS. 1. Saliferous Marls, Keuper, &c.—2. Red Sandstone and Quartzose Conglomerate (Pl. 29. figs. 1—4.).. 27 CHAPTER IV. NEW RED SYSTEM. LOWER FORMATIONS. 3. Calcareous Conglomerate.—4. Lower New Red Sandstone (Pl. 29. figs. 5. ef seq.) .... cece cece 46 CHAPTER V. TRAP ROCKS. (General view of.) Trap Rocks compared with Volcanic Products, and shown to be of igneous origin.—Distinctions between contemporaneous and intrusive Trap Rocks ............ Gite em A hee Ch ORE Ra BORE go 68 CHAPTER VI. CARBONIFEROUS SYSTEM. Introduction.—Upper Coal Measures and Freshwater Limestone in Shropshire. (Pl. 29. figs. 5—9.).... 79 X1V CONTENTS. CHAPTER VII. CARBONIFEROUS SYSTEM (continued). age : iB Coal-field of Coal Brook Dale.—Upper Coal and Freshwater Limestone.— Lower Coal or productive Coal and Iron field.—Carboniferous Limestone.—Trap Rocks and Dislocations (Pl. 29. figs. 11—17.).... 99 CHAPTER VIII. CARBONIFEROUS SYSTEM (continued). Clee Hill Coal-fields; including the Titterstone Brown Clee; with descriptions of the underlying forma- tions of Millstone Grit and Carboniferous Limestone (Pl. 30. figs. 1, 5—8.).......0.sseeeececes ade CHAPTER IX. CARBONIFEROUS SYSTEM (continued). Trap Rocks of the Clee Hills; their composition and relations; effects of their eruption. (Pl. 30. figs. OO) o ehaeseess se: CREME RC ibeeraiere «fo i SE oe rs nen nee Meese aR ie Me TE heen ee Des B 125 CHAPTER X. CARBONIFEROUS SYSTEM (continued). Coal-field and Trap Rocks of the Forest of Wyre (Pl. 30. figs. 1—9.) ........0eces ccc ceeeecceece: 131 CHAPTER XI. CARBONIFEROUS SYSTEM (continued). Coal-field of Oswestry (North Welch Coal-field), including Coal Measures, Millstone Grit, and Carboni- ferous Limestone.—(PI. 30. f. 14.) Concluding Observations on the Origin of the Salopian Coal-fields 141 CHAPTER XII. CARBONIFEROUS SYSTEM (continued). Coal-field of Newent.—Carboniferous Limestone of South Wales and Monmouthshire—Organic remains of the formation (Pl 380: aie. V0; Pl ial a tiels slo datics, 15-9. )injs seis ere aan ee 153 CHAPTER XIII. CARBONIFEROUS SYSTEM (concluded). Principal Outliers and Dislocations of the Carboniferous Limestone on the northern and western edges of the South Welch Coal Basin (Pl. 80. figs. 11—13. Pl. 31.f. 1. Pl. 34.f.6.) ................ 162 CHAPTER XIV. OLD RED SYSTEM. 1. Conglomerate and Sandstone.—2. Cornstone and Marl.—3. Tilestone (Plates 31—36.)....... 22, 169 CONTENTS. XV CHAPTER XV. OLD RED SYSTEM (continued). Page Trap-Dykes in the Old Red Sandstone; Mineral Veins; Dislocations; Outliers; Agricultural Characters Ob CHE OAMENEd YSUGMN Vga Wi LUNN NN Ce css s seed sats a ee hte Ors bees esas Chews dans dee es 185 CHAPTER XVI. SILURIAN SYSTEM. Introduction.—Upper Silurian Rocks.—1st Formation or “‘ Ludlow Rocks.” (Pl. 31. figs. 2—5.) .... 194 CHAPTER XVII. UPPER SILURIAN ROCKS (continued). 2nd Formation or ‘‘ Wenlock Limestone.” (Pl. 31. figs. 2—5.) ...... WMI robe treats de sates tuba? 208 CHAPTER XVIII. SILURIAN SYSTEM (continued). Lower Silurian Rocks.—3rd Formation or “‘ Caradoc Sandstone.”—4th Formation or ‘‘ Llandeilo Flags.” (CRLGSS BUS BOS SU Ge on bon 86 oo Goce OOo io oise sank tir Oke Cae Ur an aa 2 SI 216 CHAPTER XIX. SILURIAN SYSTEM (continued). Trap and altered Rocks of the Caradoc, Wrekin, &c.—Periods of Volcanic Eruption.—Dislocations and @ucliers omsilumanyRockes u(RIe alewhescdp ae PhS Dee teok.)) Mey ee cte ae cielo a cap eile omer saps 225 CHAPTER XX. SILURIAN SYSTEM (continued). Joints of the Silurian Rocks. —Landslips.—Wells.—Agricultural characters of the Silurian System .... 243 CHAPTER XXTI. CAMBRIAN SYSTEM. PART OF THE UPPER GROUP. Mineral Axis of Shropshire.—Cambrian and associated Trap Rocks in the Hills of Longmynd, Ratling- hope, Linley, Pontesford, Lyth, and Haughmond. (Pl. 31. f.4. Pl. 82. figs.1, 2and4. Pl. 33. f.1.) 255 CHAPTER XXII. LOWER SILURIAN AND TRAP ROCKS, LEAD ORES, QUARTZ ROCK, &c. Lower Silurian Rocks alternating with Volcanic Grits (Shelve, &c.).—Amorphous or Intrusive Trap (Corndon, &c.).—Altered Rocks and Veins of Lead.—Quartz Rock of the Stiper Stones. (Pl. 32. Fiezea Ty DIY SUT An aay SCR Re Nn SR ole 268 XVi CONTENTS. CHAPTER XXIII. THE BREIDDEN HILLS AND ADJACENT TRAP AND ALTERED ROCKS. Page Line of Dislocation produced by the eruption of the Breidden Hills, extends from Montgomeryshire through Shropshire into Staffordshire. (Pl. 32. figs. 5—8.)........ 0. cc etee cc eeee cess ceness 287 CHAPTER XXIV. SILURIAN ROCKS OF MONTGOMERYSHIRE. Range and Distribution of the Silurian Rocks in Montgomeryshire and the adjacent Districts of Shrop- shire and Denbighshire.—Their passage into Cambrian Rocks. (Pl. 82. figs. 1, 2 and 9. Pl. 38. f.1.) 300 CHAPTER XXV. SILURIAN, CAMBRIAN, AND TRAP ROCKS IN RADNORSHIRE. Upper and Lower Silurian Rocks of Presteign, the Vale of Radnor, Radnor Forest, &¢.—Cambrian Rocks in West Radnor.—Volcanic Group and Altered Rocks of Old Radnor. (Pl. 38. figs. 1—4.)........ 311 CHAPTER XXVI. TRAP AND ALTERED ROCKS OF RADNORSHIRE (continued). Group of Llandegley, Llandrindod, and Carneddau near Builth. Mineral Waters of these Tracts.— (Pl. 33. figs. 3—7. See also Map and opposite sketch of the southern end of Carneddau, near Bult) nc sets ok sere eee eed hek a Wg ge Beg eo etagd com Og a Rane LE Ree da oa 324 CHAPTER XXVII. SILURIAN, UPPER CAMBRIAN, AND TRAP ROCKS OF BRECKNOCKSHIRE. Silurian Rocks in Brecknockshire, including the anticlinal Ridge of Brecon.—Trap, altered Rocks, and Whneral’ Waters of dlanwrtyds, (laa eties 266-29) ieee ger) eee nen vi ite ee moa 336 CHAPTER XXVIII. SILURIAN, UPPER CAMBRIAN, AND TRAP ROCKS OF CAERMARTHENSHIRE. Course of Upper and Lower Silurian Rocks maintained by superposition and organic remains.—Great changes in lithological structure.—Lower Silurian where best developed—in parts affected by slaty cleavage.—Fine exhibition of Llandeilo flags, their passage into Cambrian System.—Change of strike as the strata pass into Pembrokeshire—Cambrian. Rocks.—Trap and Altered Rocks.—Mines, &c. CPL 134, figs. Dae ee ee Mie eee Seestete aipiar a leoat h Aasdee asses iain caste hat ad ch ene BR es 347 CONTENTS. CHAPTER XXIX. GEOLOGICAL STRUCTURE OF PEMBROKESHIRE. OVERLYING FORMATIONS. Introduction.—Coal or Culm|Measures.—Millstone Grit.—Carboniferous Limestone. —Old Red Sand- SUOMCHE(Ual WRG AME OMMENE ON) Emr EM Gn ety sini wre es VuW eRe tute paste theese cea anes be?) sda CHAPTER XXX. PEMBROKESHIRE. SILURIAN, CAMBRIAN, AND TRAP ROCKS. Silurian System.—Divided into Upper and Lower Silurian Rocks, with full developments of the Caradoc and Llandeilo formations.—Cambrian System and Slaty Rocks.—Stratification and cleavage coin- cident.—Trap Rocks, bedded and amorphous.—Divergent lines of strike explained by eruptive ridges Diarra (eS oe fers MA CMO TMM ita oe ip napa eh at aos Reps athe Geter ecelgceh ich wo. coe bf cern ct CHAPTER XXXI. MALVERN AND ABBERLEY HILLS. Silurian System in Worcestershire and the Eastern part of Herefordshire.—Syenite and other Trap Rocks of the Malvern and Abberley Hills, and dislocations of the Silurian System along their flanks. (Pl. 36. iE EaSTe LoS) ec Or ae ea Re orient ANN SE SOOT OT OND Un ematpg nae De : CHAPTER XXXII. WOOLHOPE—SILURIAN VALLEY OF ELEVATION. Introduction.—Form of the Valley.—Description of the Silurian Rocks which constitute its encircling ridges and nucleus.—Ancient dislocations which determined its form, fractures, and drainage.—Mo- dern dislocations and landslps.—Drifted matter. (See enlarged Map, p. 427, and coloured sections, ears ORO On ga CW OO CUIG [an EO) piss cccetume Meteo es oa jo. t yp cane) ar bet vos ta. noo Poetagei Rie aides yigeash-o ee CHAPTER XXXIII. SILURIAN GROUPS OF USK AND MAY HILL. 1. Usk Valley of Elevation, consisting, like that of Woolhope, of the Ludlow, Wenlock and Caradoc Formations. (Pl. 36. figs. 23, 24.)—2. Prolongation of the axis of Woolhope, by May Hill to Purton and Tortworth in Gloucestershire. (Pl. 36. figs. 11—14, 14 bis, 15, 16.) Ce a | CHAPTER XXXIV. ON THE ROCKS OF THE TORTWORTH DISTRICT (GLOUCESTERSHIRE). General succession of strata, from the Inferior Oolite to the Lower Silurian Rocks.—Inferior Oolite and Lias.—New Red Sandstone and Dolomitic Conglomerate.—Coal Measures.—Carboniferous Lime- stone.—Old Red Sandstone.—Silurian System.—Small development of Ludlow and Wenlock for- mations.—Caradoc Sandstone clearly exhibited.—Trap Rocks all of intrusive character.—Altered and dislocated deposits.—Strata elevated and thrown into anticlinal forms by the outburst of trap. (Pl. 36. figs. 16—22.) OE Aeee Okt) 85 0: 0 opie) ae. ayie) teh ie) Fe, je) zeta. (6) fe Te ve, “e/a: ee uo fee 16 19 0 (0) ¢ (p 9 (ee fe fe y 0 @ (Be sw ae 0 ke we et eet ea ne XVI Page 370 389 XVill CONTENTS. CHAPTER XXXV. ON THE DUDLEY OR SOUTH STAFFORD AND WORCESTER COAL-FIELD. Page Introduction.—General arrangement of the Coal-field.—Account of the Formations in descending order.— Lower New Red Sandstone.—Volcanic Grit or Tufaceous Conglomerate.—Coal Measures, including the Upper and 10 yard Coal, and the Lower or Ironstone Measures.—Shaft Sections. (Pl. 37. figs. V5.) sete SPE sae varedeanwerinie ts Pee ie Taha ls TAG ote eee Pe ee Ee Mtoe oaee EO 463 CHAPTER XXXVI. SILURIAN ROCKS OF THE SOUTH STAFFORD AND WORCESTER COAL-FIELDS. Upper Silurian Rocks (Ludlow and Wenlock formations) support the Dudley and Wolverhampton Coal- Fields and rise through them in separate masses.—Lickey Quartz Rock shown to be Caradoc Sand- stone, or Lowest Silurian stratum of this district.—Intrusive Trap and altered rocks.—Lines of ele- vation and location.—Extension of Coal Measures beneath the New Red System. (See Map and PL. 37 BS SSRN Ns ooo wie id eee Rte ER etd ace. Hue: Speak candy OWE ae Ne 480 CHAPTER XXXVII. SUPERFICIAL DETRITUS. Introduction.—Division of the subject of superficial detritus —Drifts comprised within the hydrographical region of Siluria.—Ancient or submarine condition of this region.—All its ancient drift shown to be of local origin, and caused by local agency of tides and currents, influenced by elevations of the bottom of the sea.—Such drifted matter found on slopes descending from elevated ranges, occupying both lofty and low positions.—Enormous extent of ancient denudation in the transverse valleys now watered by the tributaries of the Severn.—Distinctions between marine drift and fluviatile accumu- lations.—-Recapitulation. o2:4:,. "cater ts 6-1-1 ae ce ee Oe ee 509 CHAPTER XXXVIII. THE NORTHERN DRIFT. On a Northern Drift containing granite bowlders and sea shells of existing species, which covers large parts of Lancashire, Cheshire, Shropshire, Staffordshire and Worcestershire ; prefaced by a sketch of the probable condition of the surface before and during its deposit, comprising a short account of the local detritus which the northern drift covers and with which it is partially intermixed. .......... 523 CHAPTER XXXIX. NORTHERN DRIFT (continued). On the position of the great Bowlders which characterize the Northern Drift, and on the method of their Far CE ATESPOT be. gs a) halle sale kere tele teelb ee fel ite dase cos Fete er witaver ells tails eavenrte fader) oi oiniecere (ae eK. IRE Been eae ag RS) CONTENTS. bab.4 CHAPTER XL. SUPERFICIAL DEPOSITS (continued). wae) Page Early condition of the surface after elevation from beneath the sea.—Lacustrine and broad river period.— Passage to present condition.—Remains of extinct species of quadrupeds.—Ancient river deposits... 548 CHAPTER XLI. SUPERFICIAL ACCUMULATIONS (concluded). Terrestrial changes within the modern era.—Desiccation of lakes and turbaries.—Modern action of rivers. —Accumulations of blown sand.—Exposure of submerged forests.—Formation of shell marl and ee ORC ene nM ee Tete ie ry et. RT Reis RAG RN CD oe Germ Nes abs owl are ee eG dlerwerw Mave wise TE 558 CHAPTER XLII. CONCLUSION OF PART I.—GENERAL VIEW OF THE FORMER CHANGES OF THE SURFACE. Parallelism and divergence of mountain chains.—Ancient dislocations, and their intensity.—Vastness of scale of former depositary action.—Central heat.—Ancient dislocations and modern changes re- Coricileds scenes 3 che omorlc Gh8 apes b Rnb de Gio Abri.0 45-6 ob. b Oh Dien en ee ae eee nea ar 568 PART IL. ORGANIC REMAINS. —— CHAPTER XLIII. Introductory View of the Distribution of Organic Remains in the Older Formations ........ 579 CHAPTER XLIV. ORGANIC REMAINS OF THE OLD RED SYSTEM. Intredudticmesd®mHescePiss liye, 2tbis.)==Molluscaa&c.: (Pls 8:)i. ccs oe ee eee as et 587 CHAPTER XLV. FISHES AND SHELLS OF THE LUDLOW AND WENLOCK FORMATIONS, OR UPPER SI- LURIAN ROCKS. Fishes, &c., of the Upper Ludlow Rock, Pl. 4.—Shells of the Upper Ludlow Rock, Pl. 5.—Shells of the : Aymestry Limestone, Pl. 7.—Shells of the Lower Ludlow Rock, Pl. 8—11.—Shells of the Wenlock _-~ SLinnestiiae enndl Shaile, JEL Ie 8). eo wnacirw a rer ene mtr crack tiarhrtecc haces Riis ier snin’ aries SO) c 2 XX CONTENTS. CHAPTER XLVI. SHELLS OF THE LOWER SILURIAN ROCKS. Shells of the Caradoc Formation, Pls. 19, 20, 21.—Shells of the Llandeilo Flags, PEDO wits doy yen Stee 634 CHAPTER XLVII. TRILOBITES OF THE SILURIAN SYSTEM. General view of Trilobites.—Their geological range.—Trilobites of the Ludlow and Wenlock Formations, or Upper Silurian Rocks, Pl. 7, 7 bis, 14.—Trilobites of the Caradoc and Llandeilo Formations, ~ or Lower Silurian Rocks, Pls. 23, 24, 25.— Structure and Affinities of Trilobites .............- 645 CHAPTER XLVIII. ENCRINITES AND ZOOPHYTES OF THE SILURIAN SYSTEM. Crinoidea, Pl. 17 and 18.—Polyparia, Pl. 15, 15 bis, 16, 16 b¢s.—Other Zoophytes and nondescripts, P1.26;—Annelida of the Upper Cambrian Rocks; Pl2/ 5 ier. Seite ec en eee eee wine ;, -670 Pabular Listiof Organic Remaims). 2.) -72-).-4- 2.0. - ss teed Eee pereh- ele i eho ie 703 Description of Coloured Sections! Wie cpr it eater ere wc iets ede aeolian PE a OOS MC ra ne 408 /-V 11 (00> SN IBEG HOG Oo TOOT Oe USUUDO Uo OF COV ech Oro an Garb odae hor 6) TOOUCOTO An pe DanaOae 726 Wadex. - 20) sat te Pe eee eh et ae ee ME ar 1 Rede Re Te her eS MOM Geo oie 735 Coloured Sections, Plates 29 to 37. re XXi LIST OF ILLUSTRATIONS’, LITHOGRAPHIC SKETCHES. Page View of the Vale of Worcester and Malvern Hills from Hagley Park . . . . - se « 78 - View of the country around Shrewsbury 6 60. eee ee ee 8D View of Ludlow .. . Rn eee Ge Me ee ee oO Coloured view of the Silurian Rocks ous the anne Hills. In this and the following view the Rocks of volcanic origin are coloured bright red, the Silurian Rocks purple, as in Map... : ‘ POOR GAA aatteinond . . 216 Coloured view of the Car ibe Hills seen iow the avemtrad eee Pee ar oe go ee way PO View in the Longmynd Hills . 6 1 6 tees ie tent tat estan At ote 256 eee oC orndonelinlce.m an at ee Mh eT Rw ee AOD View of the Stiper Stones . . MURMC MIR tN SS ta et a oe ee ee te oh ee View of the Breidden Hills from Nees Clift eee e fox slebpe gees) © SIDRMIQ MIRON) 16. Jans Wel View from Powis Castle .. . ge Petey ee, MAGES DOMelQ 1p myn U2 View of the hills between Old aaibe anal Kington bewg th rabes oes een ue = ge SEEGER View of the Carneddau Hills (Builth) . . . : . ws peel FSBO Coloured panoramic view of the Silurian Rocks de Old Red Seicactie in aTaciuibalames . 346 ‘Wizure cai’ TDG Toe a ho beam ce meat le ac nae ELI a aa a meme ae e WOOD.-CUTS. QO. 1. General descending section from the Inferior Oolite to the New Red Sandstone . . . 14 Dhaceilesattheplowersuiasishale ss) aise 4s eee cy ely ee ee ld 3, Outlier of Lias in Shropshire, section across. . «© - 6 e+ 6 ee ee ee ee 88 ‘4, Relations of the Shropshire Lias to the Coal-measures, general section . . . . . - 25 5. New Red System, general descending section. . - 6 es 6 6 ee 6 ee ee 28 §. Section of the Saliferous strata at Stoke Prior, Worcestershire. . . : 31 7. Section across the upper formations of the New Red System, SEeavetine (dee ‘gs of ‘Muschelkalk?) .. . ee Ae 8 ye OR ee Ne TAD Se NS OR 8. Plant in the New Red Sindeians Se atte Ven ae reer ene Ve, ois Me AS 9. New Red Sandstone, false bedding . . . - 2 6 2 © 6 6 2 ee ee ew ee OD 10. Carboniferous System, general descending section. . - - - + + + + «+ «© «© «© 79 11. Fossils of the limestone of the Shrewsbury Coal-field. . . . . »- »- © © © « = 84 12. “Symon faults’ of the Coal Brook Dale Coal-field . . - - - + + + + «© + + 102 PC @ See the list of Plates of Organic Remains and description of the Coloured Sections, pp. 718 ef seg. XXH LIST OF ILLUSTRATIONS. No. Page igs Fossils of the Coal Brook Dale Coal-fidld nctensuctt coae-sumal® alex 2 So apceondl boca 105 i#» Coral of the Carboniferous WH dmestone. wl (elrutace ts chlo ringing? 248 34. Landslip at the Palmer’s Cairn, or Churn Peak near aoe VIC, Ofete «af ateh oe eo 4G 35. “Bone Well” near Ludlow, joints in the rocks at... ... . 4) sw ew es ~ s) 250 36. Longmynd Hills, view inthe. . . . i upery tgioltsar- aideodacdl rate sre h eee ee ee oer 20. Trap and Cambrian Rock in the een 4 e 2 ss ates VR ao Le ee eeeow 38. Trap, Cambrian Rock and bitumen at Haughmond Hil Serie tile teobloetercomengalls 2-265 SO PSLIPET IO LONES, SAlOp, View ATOM 5 | asus wiueees i) ct Remo 0 nn ae as AO, Volcanic Grit, view of quarry Of. 22.5. Gar £51} netuenlaih Gena ateemoeaeee easel. 0 41, beds 10 face" nyt ae) eel st) oe eehied iii ales Boat oeisael Oe eo j Bouptive tvap rocks im the-Comdon: Hille’ (2°20, Sea ea ae eee ae ee 274 44, Trap dyke and altered rocks in the Corndon Hills . ... . . 1. . 4. su. 294 45.. The Breidden Hills, view of their-summit. 4 (:\-tp-p.ocleI- espe pe) chested oor 46. Trap rock of Nantcribba, Montgomeryshire, section . . . . . «... . + » « » §288 47. Trap rock of the Standard Quarries, Welch Pool, view of . . . .... =. =. =. 288 48, Union of concretionary and prismatic trap at Welch Pool . . . . . 2... . . OQ89 49, Trap and altered rocks, Moel-y-golfa, Breidden Hills. . . . 2. 2. 2 1 4» oe v2.93 5O.. Powis Castle, sectionat . .. « 2 ©» estieeeen gph ni ed Bobi cee ered 5i., Contorced ‘Upper Silurian Rocks... » . «toate nyuetade as acqpe aictecaneS eeniae a OG 52. Nash Scar, Radnorshire, altered limestone of . . . . . ee eee ee a 53. Trap rock of Old Radnor, throwing off limestone and Sl ISG Sb wc, otcosc®) geget¥S 19 ° } rap and: altered rocks near Old Radnor “0% S22? eS eae eee ROK) No. 56. Altered limestone of Nash Scar,near Presteign . . . . = - Faye cle € 57. Alternations of bedded trap and Lower Silurian deposits near iimnaente 58. Trap and altered schist, Radnorshire. . . . 2 + + + 5 © © ee 59. Trap and altered shale near Builth . . . - » «© » ws 62 ° LIST OF ILLUSTRATIONS. . Trap and altered rocks near Builth ; ll a Dae . Trap and altered rocks with mineral spring, Builth . Pa Ieee as Llanwrtyd Wells, Brecknockshire, view near. . . . . . = - 63. Brecon anticlinal; transverse section of Ludlow rocks. . .. . 64. Porphyritic and altered rocks near Llanwrtyd, Brecknockshire . . . . . 65. Vale of the Towy, Caermarthenshire, view of . . . . Tae, ae 83. ; : . Intrusive trap and Upper Silurian Rocks, Marloes Bay, Pombronesttie ‘ 92. . Silurian strata dislocated by Malvern syenite . . . . Ane beads ye ae ee ee ar . Veins of Gogo-fau, Caermarthenshire . . . 2. 2 2 «© © 2 © es . Stackpole Rock, Pembrokeshire, view of . . . + + + + + 2 + « . Transverse general section of all the sedimentary groups in Pembrokeshire . . Culm or coal resting on Silurian Rocks, Pembrokeshire . Culm or coal resting on Cambrian Rocks, Pembrokeshire . . .. . . “Slash” of culm, Pembrokeshire, with contorted and broken strata . Stackpole, cliffs of contorted carboniferous limestone, viewof . . . . . Skomer Isle, &c., view of, from the main-land, Pembrokeshire . . Marloes Bay, Pembrokeshire, seen from the west, view of . Marloes Bay, Pembrokeshire, sectional view in . . . . . . + « 5 | Cleavage coincident with stratification in Pembrokeshire explained . Trappean conta etale and dislocated Old Red Sandstone . . Malvern Hills, view on the western flanks of . . Section of Volcanic Grit . ‘ . Malvern Hills, general slight sketch ie ae be. east . . Arched strata and syenite, Malvern Hills . Silurian strata reversed in the Abberley Hills . } Wenlock Limestone dislocated on a line of volcanic fissure, ground plan . Silurian strata reversed by Malvern syenite . .... . . Wenlock Limestone near the Malverns, contraction and-expansion of . . Woolhope Valley of Elevation, transverse section of Tht . Purton Passage on the Severn, showing arched strata upon an anticlinal line . Tortworth Terrace, Gloucestershire, view from Mitzprock mean dortworthy 4 2 2 « % G % ste + ie « . Noeth-griig, Caermarthenshire, sectional view of, to show the difference between cleavage : Slaty cleavage, concretions, and beds of Cambrian Rocks, Caermarthenshire .. . XXIV LIST OF ILLUSTRATIONS. No. Page 100. 101. 102. 103. Wren's Nest, Dudley (Souther end), view of = 2) fan) es oe en eee elas 104, Rowley Hills, basaltie quarry, view of 8.0.2 be a ee eg 105. A : 500 18 f Faults in the Dudley coal-field near the trap of Barrow Hill . . ..... | oy, 107. (Gravel-and sand near :Shrewsbury,isection Of (yar) 2 2a 9 ca eee 2 Bee os eae 108. Seaeshells with sand and gravel near Shrewsbury (section) . . . . . .. =... S8l LO9. Wee-oes in thesPacihicwviewsot wy is ws wee! ex! an Cente et tee 2 ee, AO. yrolese Mps psectionvacrOgs tt). sss) oe a gee gee ee eee ee tm 111. Raised beach, sectionof . .. . ee MT aie a Cet a ee eM oe ok iL 112. “Southstone Rock,”’ a travertine Soro aibes WAGE me eee oy bce crate the ge ons ge ee } Dudley coal-field, general relations of before and after elevation . . . . . . . 465 | Wen's Nest, Dudley, ground plan and transverse section of . ...... . 484 MAPS ACCOMPANYING THIS WORK. . Map of the Silurian Region, geologically coloured (detached). . Small Map of England, divided into Geological Systems (corner of the large Map). - Map (small) of North American Lakes . . . BS eae MS asaya et . Ideal Map of the relations of sea and land nee ie sdetauleGon of the cometaeaics of the midland counties . . . jelomen eae 5. Map of the Valley of Woolhope ie seeing tract ecae 1 “Aaeli to a deals hen Ane Hm ©8 bb = PLATES IN WHICH THE ORGANIC REMAINS ARE FIGURED. Inserted in Part II. , | ies of the Old Red Sandstone ..... . eer emreee Mie ae ty oc 2 9 | 3 Shells in the lowest beds of the Old Red Sandstone .......2. +... 602 Ave 4 Bishesiot thes Upper: Ludlow Mxocke s-o5c Whe, -alee Cal vibes ster, oe en Ls 5 Shells of the Upper Ludlow Rock .. . eee ee Sere 2 eG 6 Shells of the Aymestry Limestone or Middle padlen Rock Sa eT Mee aS i : | ilobtes of the Ludlow and Wenlock Rocks(Upper Silurian) . . . . . . . 651 Ws. Shells olathe dower Tudlow- ROG — gi ie one Mit Shee, - ee sb ee eee ee eae 10, | chambered Shells ofthe Lower, Ludlow Kock. ss. «isn sl Gs Bea. so OL ll. LIST OF ILLUSTRATIONS. Plate 12.. Shells of the Wenlock Limestone 13. Shells of the Wenlock Shale 14.. + Trilobites of the Wenlock Formation 15, 15 bi 6 ” Corals of the Silurian System . 3 16 bis. nies i Encrinites 18. 19, ne | Shells of the Caradoc and Llandeilo Formations (Lower Silurian) 3 99. J 23, OAs Trilobites of the Lower Silurian Rocks Qbs 26. Miscellanea and non-descripts, from the various Silurian Rocks 97. Annelids, or Sea-worms of the Upper Cambrian Rocks 29. 30. ol. 32. 34. 35. 36. 37. (In all 31 Plates of Fossils.) PLATES OF COLOURED SECTIONS ILLUSTRATIVE OF PART I., Inserted at the end of Part II. Sections illustrating the relations of the Strata in Gloucestershire, Worcestershire, and Shropshire, chiefly those of the Lias, New Red Sandstone, and Coal Measures, seven- teen figures . . . 2 8 Sections of Coal-fields id Cavboniter ous hee: Wes in in Shropshire (Clee Hills, Os- westry, &c.), fourteen figures . Old Red Sandstone and Silurian Rocks, chiefly Teves Silurian, i in Sam a Bi tacae shire, nine figures . . . ow bm Silurian Rocks, and Cambrian Boeke with oe and alteusa Rocks ‘aia Mines, i in “Salon and Montgomery, nine figures. 5 S. Seta Silurian, Cambrian, and Trap Rocks, &c. in Radnor Sevem dieures= . 5 sae Caermarthenshire Sections, eleven figures . . . . Pembrokeshire Sections, eleven figures . Sections in the Abberley and Malvern Hills, ales of Winalhones Moy 2 Hill, TRE: Usk, and Chepstow, twenty-four figures . . ... . co teen ReCuons across the Dudley and adjoining Coal-fields, Lickey Hills, ae nine Shatiite oy 0 XXV Page 622 628 655 675 670 634 659 696 699 ERRATA. Pages vii. and 386, e¢ passim, for Narbeth, read Narberth. Page 25, line 29, for (Pl. 29. f. 33.), read (Pl. 29. f. 2, 3.) Page 38, line 30, for (Pl. 1. f. 2.), read (Pl. 29. f. 3.) Page 44, line 20, for underlying systems, read underlying for- mations. Page 49, line 13, for (See Chanter 5.), read (See Chapter 6.) Page 64, line 9, for (Pl. 30. fig. 13.), read (Pl. 30. fig. 14.) Page 89, line 21, for Mr. Loomy and Mr. Miller, read Mr. Looney and Mr. Mellor. Page 125 et seg., for Abdon and Clee Barfs, read Abdon and Clee Burfs. Page 151 note, line 6, for compact cone, read compact coal. Page 164, line 31, for the two concluding Chapters, read the concluding Chapters. Page 170, line 20, and page 171, line 20, for Brecon fans 2500, read Brecon fans 2860. Page 173, line 7, and page 516, line 30, for Black Mountain, read Black Forest. Page 177, line 10, for (Pl. 36. f. 21.), read (Pl. 36. f. 24.) Page 180, line 7, for Bromsgrove, read Bromyard. Pages 181 and 182, for Pont-ar-lleche, read Pont-ar-llechau. Page 183, line 32, for (Pl. 37. f. 8.), read (Pl. 36. f. 8.) Page 202 note, line 2, for Mr. Davies, read Mr. Davis. Page 215, line 13, for S. trapezoidalis, f. 14., read S. trapezot- dalis, Pl. 5. f. 14. Page 217, line 21, for P. oblongus, f.9 and 10, read P. oblon- gus, Pl. 19. f. 9 and 10. Page 218, line 12, for Avicula orbicularis, Pl. 15. f. 2., read Avi- cula orbicularis, Pl. 20. f. 2 and 3. Page 219, line 5, for dvicula obliqua, PJ. 19. f. 4., read Avicu- la obliqua, Pl. 20. f. 4. Page 219, line 5, for Orbicula granulata, Pl. 19. f. 5., read Or- bicula granulata, P\. 20. f. 5. Page 219, line 5, for Orthis Pecten, Pl. 20. f.9., read Orthis Pecten, Pl. 21. f. 9. ~ Page 219, line 10, for Tentaculites annulatus, Pl. 19. f. 15., read Tentaculites annulatus, Pl. 19. f. 16. Page 303 note, line 5, for Trinucleus Caractacus, read Trinucleus Caractaci. Page 327, line 20, for The same at aopcraded read The same occurs at Llandrindod. Page 340, line 32, for Serpuloides longissima, read Sen pilites longissimus. Page 350 note, for is in the equivalent, read is the equivalent. Page 363, line 6, for Pl. 30., read Pl. 27. Page 366, line 13, after “ mines” insér¢ (Pl. 34. f. 4.) Page 370, line 4, for the present chapter, read the present and following chapter. Page 398, line 36, for Castle Rock, read Roche Castle. Page 473 note, for Mr. W. Barker, read Mr. J. Barker. Page 493, line 17, for Clent and Abberley Hills, read Clent Hills. Page 501, line 14, for old clay works, read old day works. Page 504, line 13, for inclined from 80° to 90°, read inclined from 60° to 70°. Page 510, line 14, for travestine, read travertine. Page 522 (heading), for Detritus of Silurian Recapitulation, read Detritus of Siluria.—Recapitulation. Page 582, line 3, for Serpuloides longissimum, read Serpulites longissimus. Page 583 nofe, line 21, for Homanolotus Herschelii, read Ho- malonotus Herschelit. Page 616, line 1, for vetustis, read vetustatis. Page 619 et seg., for Bar Beacon, read Barr Beacon. Page 627, line 23, for Bellerophon apertus, read Bellerophon Wenlockensis. Page 637, line 34, for Damory Hill, read Damory Mill. Page 639, line 17, for Corton, Clunbury, read Corton, near Clunbury. Page 643, line 1, Lituites ? Cornu-arietis (a), ought to have Peer described as a fossil of the Wenlock Shale. N.B. Although the words “ Caradoc Sandstone ” are prefixed to - Pl. 21, and ‘ Llandeilo Flags” to Pl. 22, the first of these plates contains forms (f. 1 and 2) which occur in the “ Llandeilo Flags,” while there are shells in the second (f. 2%, 2°, 11, and 12) which are referrible to the ‘‘ Caradoc Sandstone.” Description. _ See Tabular List and XXVil DESCRIPTION OF THE MAP. Tax accompanying Map is intended to convey a clear general idea of the geological divisions of the surface of the tract illustrated, the details being explained by numerous coloured sections. It is a reduction of the Ordnance Survey, and therefore exhibits accurately the drainage and the relative positions of the towns and villages: the form of the hills is not delineated, but as many of the heights are marked by figures, and the names of the ridges are inserted in the line of their di- rection, it is hoped that the general features of the country will be understood. In the selection of colours, I have represented each great system of strata under one common tone, and its sub-formations by modified tints of the same colour. The calcareous rocks of all ages appear under shades of blue. or green; the formations to which they are subordinate being known by the colour which surrounds them. The rocks of igneous origin are all represented by bright red, a method which I have employed for some years', from having thought that masses, the varieties of which pass imperceptibly into each other, ought at once to strike upon the eye as being derived from the same source. But after all, as colours are fugitive, and details of high interest are often crowded together into small spaces, I have inserted Jetters at intervals (par- ticularly on the sectional lines), the meaning of which is at once explained by reference to the table of superposition. In addition to the tabular arrangement, usually employed by other authors, I have placed below the map on the right hand, a general transverse section, in which the sedimentary formations and their subdivisions are represented in the order in which they naturally overlie each other, where no volcanic rocks are present ; whilst on the left, an ideal section is given of the submarine condition of these sediments before their elevation from beneath the sea, to mark the periods when volcanic action was most in play, either when giving rise to fine detritus of scorie and ashes, accu- mulated in alternating layers with sand and mud; or during the emission of those intrusive rocks, which, whether syenites, greenstones, porphyries or basalts, are all the products of fire. Many of these volcanic rocks being inseparably connected, even within small areas, and in the same ridges, their lithological distinctions can only be understood by consulting the explanations in the text ; but the epochs at which they are supposed to have been erupted, are signified by different letters,—their relations to the sedimentary deposits being rendered more intelligible by reference to the plates of coloured sections (see Plates 29—37). A small map of England and Wales has been engraved in the corner of the large map, for the double purpose of pointing out the geographical site of the Silurian Region, and of subdividing the kingdom geologically into eight sedimentary groups, each of which I conceive (in British classifi- a ac nN I a 1 In the Map of the Eastern Alps, Geol. Trans., vol. iii. Pl. 35., and in the coloured Ordnance Maps of the Silurian Region exhibited at various meetings of the British Association, and at the Geological Society from 1832 to 1837. I am glad to perceive that Mr. Griffiths has adopted this method in the new Geological Map of Ireland. d 2 XXKVII DESCRIPTION OF THE MAP. cation), to be entitled to be called “ Systems,’’ from their dimensions, lithological characters, and zoological contents, In comparing, however, the rocks of our own land with those of foreign countries, it is not con- tended that each of these systems has a general or even an European range. The Old Red Sand- stone, for example, so vast an accumulation in the British Isles, is scarcely apparent throughout a large part of the continent, while the deposits which I have termed the “ New Red System,” though thus arranged in England, may not satisfy some geologists of the French or German schools. The latter may contend that in their country, the “‘ Keuper,”’ “ Muschelkalk ”’ and “ Bunter Sandstein,”’ form a natural group (the Trias), which is separable from the underlying “ Zechstein ” and “ Rothe- todte-liegende ’’ by valid distinctions. In the region, however, which I describe, such distinctions do not exist. On the contrary, all the strata between the Lias and the coal measures are com- posed of red and green marls and sandstones, with conglomerates, both siliceous and calcareous, the lower members of which pass gradually downwards into the Carboniferous System. This subject is fully explained in the work; and I merely now allude to it, in order to show that in these tracts the natural order of this part of the series consists in the Carboniferous System being over- laid by one red system and underlaid by another. In regard to the subdivisions of the overlying red system, some foreign geologists are, I believe, of opinion that the fossils of the ““Zechstein ”’ and “* Rothe-todte-liegende ” agree better with those of the carboniferous epoch than with those of the overlying red sandstone, but this point is, Iam led to believe, far from being satisfactorily adjusted ; for although there may be a species or two of Mollusk common to the Magnesian Limestone and the Mountain or coal Limestone, the great mass of the fossils of the two formations are distinct. That the fishes are distinct has been clearly proved by M. Agassiz, while no researches have yet brought to light a Saurian in the coal measures, though several species of this class occur in the Magnesian Limestone. This last-mentioned zoological distinction is so strong that it seems to me to outweigh in value any conclusions drawn from the Mollusca. Again, if an identity between one or two species of Mollusca is to be made the groundwork for grouping together the Magnesian and Mountain Lime- stone, we may for the same reason connect the Magnesian Limestone with the overlying group (the Trias of the Germans), because the lily encrinite of the Muschelkalk, and, if I mistake not, a cham- bered shell of that rock have been discovered in the Magnesian Limestone. As, however, the Silurian region exhibits passages from every formation into the overlying and underlying strata, so must of necessity the lines of demarcation be more or less arbitrarily drawn ; and all that I seek to prove is, that the classification now put forth is best suited to this part of England, however little it may be adapted to other countries. In short, whatever may be the arrangement on the continent, British geologists have reason to claim for themselves the privilege of defining the upper and lower limits of the great Carboniferous System, seeing that it is more copious in our country than in any other part of Europe. But to return to my own map. An effort has been made to separate the New Red Sandstone into three distinct bands. Jor the first time in English geology, the ‘‘ Keuper Sandstone ”’ is shown to lie in the upper red or saliferous marl', whilst beneath it is the ordinary New Red Sandstone which overlies the ‘* Lower New Red Sandstone,” the two last-mentioned deposits being usually separated by a calcareous conglomerate representing the Magnesian Limestone.? ' A memoir on the Keuper Sandstone of Worcestershire and Warwickshire by Mr. H. E. Strickland and myself is in the press, and will shortly appear in the Transactions of the Geological Society. * In the map I have made use of three tints of light reddish colour to distinguish, Ist, the Red Marl and its DESCRIPTION OF THE MAP. XXIX Of the demarcations of the Old Red and Silurian Systems, it is unnecessary that I should. now speak, as they are so fully treated of in the work; yet as these parts of the map are more especially illustrated by myself, I crave the indulgence of those who may follow me; begging them to consider, not merely how little the region had been previously explored, but also how much aid the geologist is deprived of in a tract where there are few mines or underground operations'. Still. I venture to hope that this map may serve as an auxiliary to the illustration of the Ordnance Maps which is proceeding under the direction of M. De la Beche, and I trust that my labours will aid him in laying down the outlines of the various groups of rock in this region ; though there can be no doubt that the details may be much improved by the discoveries of himself and his assistants. It now remains for me to express my thanks to those friends who have aided me. Professor Sedgwick determined the outline between the Silurian and Cambrian Rocks, from the Berwyn moun-~ tain northwards. (See Map.) Mr. Lonsdale defined the course of the oolite and lias of the Cottes- wold Hills. Mr. H. E. Strickland traced the boundary between the lias and red marl, as wellas the line of the Keuper Sandstone throughout a large part of Worcestershire. The Rev. T. Egerton assisted me in laying down the boundary of the lias of North Salop. Mr. F, Downing enabled me to trace the boundary of the 10 yard coal-field of Dudley; Mr. Prestwich’s map of the coal-field of Coal Brook Dale has been highly serviceable, as well as that of the coal-basin of the forest of Dean and adjacent country, by Mr. Maclauchlan ; Sir Philip de Grey Egerton indicated the boun- dary of a small coal tract in North Staffordshire, and Mr. Bowman determined the outline of the Denbighshire coal-field. In the other coal-fields I have chiefly depended upon my own observa~ tions. I must further state, that after my map was engraved, an important improvement in the outline of the Carboniferous Limestone on the western flank of the south Welch coal-basin was kindly inserted by Mr. W. E. Logan, (see the transverse faults east of Llandovery and Llandeilo,) who with great perseverance and ability had, unknown to me, laid down upon the Ordnance Map many details and remarkable dislocations of the Glamorganshire basin, the northern, eastern, and western boundaries of which are all that I allude to®. I have to thank Colonel Colby, Lieut.-Colonel Mudge, and Major Robe employed on the Tri- gonometrical Survey, for their ready compliance with my wishes, in furnishing me with outlines of tracts, the sheets of which were not published when I commenced my researches, and I am also much obliged to Mr. Maclauchlan and Mr. Budgen, Ordnance Surveyors; to the former for much geological, the latter for some local valuable topographical data. ‘The reduction, engraving Sandstone or the Keuper; 2nd, the Red Sandstone or Bunter Sandstein ; and, 38rd, the Lower New Red or Rothe-todte-liegende, and wherever the two last-mentioned formations are known to be separated by the cal- careous conglomerate or equivalent of the Magnesian Limestone, its course is indicated by a green stripe. In a note, p. 66, printed before I decided upon the extent to which the subdivision of colours could be applied to the map, it is stated that two tints of red only are employed in illustrating the New Red System, 1 Although no one had pointed out the subdivisions of the older rocks near Ludlow, I am bound to state that Messrs. R. and W. Wright of the Ordnance Survey, have laid down very correctly the general outline of the Ludlow promontory in a map presented to the Geological Society. 2 By reference to p. 165, printed a year-and-a-half before I became acquainted with the observations of Mr. Logan, it will be perceived that I had noticed the great transverse dislocations near the Caermarthen Fans in my earliest visits to SouthWales 1832-3, I had not, however, laid them down with that precision which marks the field work of Mr. Logan. XK DESCRIPTION OF THE MAP. and writing, as well as the colouring of the map and sections, (after models furnished by myself) are the work of that able and accurate, practical geographer, Mr. Gardner. Lastly, 1 must declare, that to whatever extent my observations may have changed its outlines, the map of Mr. Greenough is the foundation on which I have worked; and no circumstance will more gratify me than his approval of my labours, or to find that any efforts of mine may enable him to improve the new edition of his valuable map of England and Wales. >) XXX1 NOTICE OF THE ANCIENT TOPOGRAPHY OF THE SILURIAN REGION. We are assured by Tacitus, that the Silures were the most powerful and warlike nation of South Britain, impatient of domination, and of great valour. Such was their confidence in their Chief Caradoc (Caractacus), and so exasperated were they by the vow of the Emperor Claudius to exterminate their race, that they carried on a stubborn war, not only under their great leader, but long after his capture; defeating the legion under Manlius Valens, and wearying out Ostorius, who died exhausted with efforts to subdue them. Veranius at- tacked them in vain, and they were not finally conquered till the reign of Vespasian, by Julius Frontinus. We have no precise definition of the geographical limits of the Silurian kingdom, though Cluverius and Camden state, in general terms, that it embraced the greater part of South Wales, including Herefordshire, Radnorshire, Brecknockshire, and Monmouthshire; it constituted, therefore, a large portion of the country described. Judging from the natural features of this region, I venture to believe, that the historian Hume has not erred in supposing that it extended to the banks of the Severn'!, which noble river, in some places, with the ranges of the Abberley and Malvern Hills in others, are the only natural boundaries, on the north and east suited to a powerful race who inhabited all the adjacent territory on the west. If Siluria was thus bounded, the north-western part of Worcestershire and the southern half of Shropshire were also included in it. Other geographical considerations confirm this supposition; for as we know that the Teme flowed through the Silurian territory, the passes and hills around Ludlow must have been within it; and no one who has ever placed his foot upon Mocktree Forest, or the Wenlock Edge, will believe that an enterprizing race would re- main contented with the possession of one end of a chain without a flank defence, while the other offered them a strong natural boundary in the gorge of the Severn. Again, it cannot be doubted, that the striking ridge of Caer Caradoc®, which ranges through the centre of South Shropshire, derived its name from some of the numerous exploits of the great British chief, whose name has been thus preserved for ages, though all the surrounding tract has so long since passed from the Celtic race. Although, however, this hill bears the name of Caractacus, it is clear that his Jast great battle was not fought on it, since Tacitus describes a rapid and deep river (vado incerto), over which the Roman soldiers forded to storm the opposite heights; and there is no stream larger than a feeble rivulet near Caer Caradoc. If the battle was fought on the northern banks of the Teme, as is pretty generally supposed, it may have com- menced at Holloway Rocks, about two miles below Knighton, where the Ludlow formation presents a stony and rugged line of escarpment on the left bank of the Teme, which completely recalls the graphic language of Tacitus, while the river answers well to his ‘‘ vado incerto,” through which the legion passed. This spot agrees also with the description of the historian, in being contiguous to a British camp called the “‘ Gaer’’ or “‘ Caer” in which Caractacus probably made his great stand, and from whence, when dislodged, he retreated into the fastnesses on the north and west, Clun Forest, Stow Hill, &c. (See Map, Camden’s Britannia, vol. ii. p, 404.) Some antiquaries have supposed that the last battle of Caractacus was fought on Coxwall Knoll, near Leint- wardine, and lower down the Teme, but this appears to me at variance both with the words of Tacitus and the skill of Caractacus; for this knoll, as the name implies, has no rocky precipitous face (arduis montibus), and 1 History of England, vol. i. p, 1. 2 In speaking of the Cardok, Cradock, Querdock or Caradoc, as it has been variously written by previous authorities, Dr. Gough, in his Edition of Camden, cites Pennant, who after showing that it could not have been the scite of the iast battle of Caractacus, yet adds, “It is highly probable that it had been a post occupied by and named from Caractacus. I¢ has been considered from very remote times a stronghold of his,’ XXXli NOTICE OF THE ANCIENT TOPOGRAPHY OF THE SILURIAN REGION. moreover is so insulated and detached from the hills, that had the battle been fought upon it, the Silures must have been surrounded by the victorious Romans, and could never have escaped into their mountains. The wily chief had evidently chosen a better position for his last struggle, and had wisely secured a safe retreat. In fact, Caractacus, though beaten, not only escaped himself from this hard-fought battle, but his people carried on the war for a long subsequent period, after their King had been sacrificed through the treachery of Queen Cartismunda, in whose hospitality he confided. But however antiquaries may eventually settle the precise demarcation of the geographical limits between. the Silures and their less powerful neighbours the Ordovices, Cornavii and Demete, geologists have already honoured me by sanctioning the term “Silurian ;” because the rocks which I describe under this name, in and around the Silurian Region, occupy a definite place in the series, and fill up a wide interval in the chronology of geological science. (See Introduction, Chap. I.) 1 The Rev. C, H. Hartshorne, who is preparing for publication a beautifully-illustrated work on the antiquities of Shrop- shire, entitled “Salopia Antiqua,” particularly in relation to the remains of military stations, informs me, that after per- sonal examination of the chains of the British camps and fortresses, he has come to the conclusion, that the last battle of Caractacus was fought upon the Breidden Hills. My chief objections to this opinion are, that the Severn is there too powerful a stream to be forded by infantry, except in remarkably dry weather, and that the volcanic hills in question are so insulated (see views, pp. 290, 300), that it would have been difficult for a large number of the discomfited Britons and their king to have escaped into adjoining fastnesses when attacked by so good a soldiery as that of Rome. I speak, however, merely as an old soldier, being incompetent to enter into this learned controversy, which I leave to be settled by an appeal to that eminent scholar and antiquary the Bishop of Litchfield, who is well acquainted with the ground. In the mean time, I anticipate much instruction from the etymological researches of Mr. Hartshorne; and I regret, that not having been aware of them until after the greater portion of my work was printed, I have not been able to profit by them. He informs me that the name of Stiper Stones (p. 283) has its origin in the Icelandic steypa (fusio metallorum), a term singularly well applied to the fused and altered rocks of the metalliferous tract. Tétterstone he derives from the Ice- landic, to shake or totter, and he has substantiated the inference by clearing away the surrounding detritus from one of the columns of basalt on the summit, which he found to be a rocking stone. Wenlock, anciently Wimnicas (the place of wind), Latin Venti-locus, Venti loc, Wenti loc, Wenlock. The Hoar Edge (pp. 121, 220), is the boundary edge, &c. I sincerely hope that this zealous antiquary will extend his inquiries from Shropshire southwards throughout the Silurian Region; for his “Siluria Antiqua” will, to many readers, have greater attractions than my “ Siluria Antiquior.” 5 ale ae ee ony ‘wing eh, Seige aay ES SS Se 4 ine ip ee’ cas an ae CHAPTER I. INTRODUCTION. Design of the work.—Previous state of geological knowledge.— Order of the older _fossiliferous strata.—Interval to be filled up, between the secondary deposits previously described, and the older slaty rocks.—Origin of this inqury, and method pursued in following tt out.—General view of the oldest fossiliferous deposits. THE chief design of the present work is, to fill up an interval in geological history, by describing certain strata, which, although they occupy a considerable thickness in the crust of the globe, and connect the secondary deposits with the older slaty rocks, have never yet been adequately examined. | A few words will explain the previous condition of this subject.—When the materials of the earth’s crust first became a subject of study, they were viewed principally with reference to their mineral characters ; but the attention which was afterwards directed to the imbedded animals and plants, gradually produced a revolution in the science, and gave birth to what is now the largest and most important part of Geology. Since the period when Smith in England, and Cuvier and Brongniart in France, first identi- fied strata by their fossils, a most rapid progress has been made in the application of this method of testing the age of rocks. Sixteen years have now elapsed since Conybeare and Phillips, in their Outlines of the Geology of England and Wales, presented us with a connected view of the succession of the sedimentary British deposits, from the most superficial to those which support the carboniferous system ; and, in the succeeding years, great and important additions have been contributed to our acquaintance with the youngest or tertiary deposits particularly by Mr. Lyell. ) , . But this method has not been so extended as to carry the chronological succession below the Old Red Sandstone ; partly, perhaps, from a preconceived opinion, that few organic remains were likely to be detected in these formations; partly from the belief, founded on just but inadequate observation, that the many mutations which these older rocks had undergone, must have nearly obliterated the evidences of their origin, whether consisting in a clear order of superposition, or in distinctness of zoological contents. A2 4 INTRODUCTION. Though, undoubtedly, such reasons deterred many from grappling with this inquiry, it must not be supposed that the ancient strata have not been studied by enlightened observers. In Great Britain we may cite the names of MacCulloch, Greenough, and Sedgwick, as those of men prominently distinguished in throwing light upon them :— the first by long examination of the Scottish mountains and numerous writings upon them ; the second by his map of England and Wales; the last by his exposition of the order of the rocks in the north of England, a portion of which task Professor Phillips has since followed out, by publishing a monograph of the carboniferous strata. But these authors had not the peculiar advantages which have fallen to my lot; for in the regions which they studied, there is generally an abrupt boundary-line or break between the older and newer systems. For example, in Scotland there is no sequence of fos- siliferous strata beneath and connected with the Old Red Sandstone; neither is there such a sequence in Cumberland, Westmoreland, nor the adjacent tracts of Yorkshire, nor even in Devonshire, where some of the oldest masses exist. In fact, a perfect and unbroken series of links, connecting these older rocks with the younger deposits, does not occur in any portion of these islands which had been previously examined. On the continent, where great attention had been bestowed upon the older and crystalline rocks, from the days of De Saussure and Werner to our own, the same belief was impressed on the minds of geologists, that the great dislocations to which these ancient rocks had been subjected, had entirely dissevered them from those fossiliferous strata with which we were well acquainted. Im short, there existed no foreign work in which rocks of this age were classified according to a law, founded upon superposition and characteristic organic remains. But to proceed to facts connected with our own country. No one was aware of the existence below the Old Red Sandstone, of a regular series of deposits, con- taining peculiar organic remains. For example, although it was supposed, that the limestone of Dudley was of greater antiquity than the Old Red Sandstone, no one had observed that those deposits were connected by an intermediate formation of very considerable dimensions, full of organic remains. It is this formation, now termed the ‘‘Ludlow Rocks,” which seems to have most escaped attention, whilst, from its position, as will appear in the sequel, it is the key which accurately reveals to us the relations of the inferior masses to the overlying strata with which we formerly were acquainted. | Of the few memoirs which had been published in the Geological Transactions, relating to parts of the region illustrated, the earliest are by Mr. A. Aikin. That accurate ob- server had formed a project of describing Shropshire in detail; but having long abandoned his intention, he no sooner heard of the progress I was making in the present work, than he placed at my disposal his original notes and drawings, illu-— strative of certain tracts around the Wrekin and the Caradoc. In truth, at the early period when Mr. Aikin undertook the task, it was almost hopeless to attempt to unravel INTRODUCTION. 5 the structure of Shropshire; for that county not only contains every sedimentary formation from the lias to the slates inclusive, but is also rendered most complex by the numberless dislocations of the strata, through the agency of volcanic rocks. The only other modern writers who had touched upon the ancient rocks of this part of England, were Mr. Leonard Horner in a memoir on the ‘‘ Mineralogy of the Malvern Hills,” Mr. Weaver in one on the ‘‘ Geology of the Tortworth District,” and Mr. J. Yates ina short paper on “‘ Parts of the central Counties.” These essays which are included in the Geological Transactions, though constituting valuable additions to our knowledge at the periods of their publication, had reference to limited tracts only, in most of which anomalous and disrupted relations prevented the adoption of any general view of a succession of the strata. In this condition of the subject, I first explored the borders of England and Wales in 1831. The order of succession seen in the ridges on the left bank of the Wye, between Hay in Herefordshire and Builth in Brecknockshire, where the Old Red Sandstone is distinctly underlaid by grey fossiliferous strata, first led me to suspect, that I had met with a district containing a good part of the evidence required to lead to a systematic study of our older formations ; a surmise which was confirmed by fol- lowing out these rocks upon their line of bearing to the neighbourhood of Ludlow and Wenlock, where I found them much expanded. I explained my view of the subject to the first meeting of the British Association, held at York, and afterwards to the Geological Society of London. Perceiving, however, that a subject so new and so large could not be really advanced, except through patient and repeated examination, I re-explored the same districts, in 1832, and submitted details of the new acquisitions to the Geological Society ; accompanying my memoirs with a set of geologically co- loured maps of the Ordnance Survey. An effort to classify these deposits was then made ; but it was not until the close of the summer of 1833, that I was enabled to publish a tolerably correct synopsis or table of the various formations in the extensive region, over which my observations had progressively extended. Seven years have since elapsed, during which my attention has been almost exclusively given to the development of this subject and its collateral branches. During the summer in which my first observations were made, Professor Sedgwick commenced a general inquiry into the structure of North Wales, for which his previous acquaintance with the slaty and crystalline rocks of Cumberland eminently qualified him. He first endeavoured to connect the transition rocks of the age of Dudley with certain calcareous slates pointed out by Mr. Greenough in North Wales; but finding no concordance between them, he was, to use his own expression, ‘‘ driven to a new base line,” in other words, to work upwards from the central axis or oldest rocks of Wales. As soon as he perceived that I had observed the links which connect the Old Red Sandstone with some of the inferior masses of his region, he felt the importance of 6 INTRODUCTION. pushing the inquiry, and by his encouragement I was materially stimulated to do so. In speaking of the labours of my friend, I may truly say, that he not only shed an en- tirely new light on the crystalline arrangement or slaty cleavage of the North Welsh mountains, but also overcame what to most men would have proved insurmountable difficulties, in determining the order and relations of these very ancient strata amid scenes of vast dislocation. He further made several traverses across the region in which _ 1 was employed, and, sanctioning the arrangement I had adopted, he not only gave me confidence in its accuracy, but enhanced the value of my work by enabling me to unite it with his own ; and thus have our joint exertions led to a general view of the sequpnee of the older fossiliferous deposits. In the mean time, some kind friends who had watched the progress of my labours, and thought they might lead to important results, requested me to prepare a separate treatise; and although I had been at first desirous of confining these views (as in the case of every memoir I had previously written) to the Transactions of the Geological Society, my objections were overcome by a very flattering requisition’. In obeying this call, I hope I shall, at all events, promulgate some new facts, and place before geologists the history of a system of deposits, authenticated by numerous good evidences in the shape of organic remains, by far the greater part of which have never been published in any country. While maturing these views, I became convinced that, as this large and ancient group contained peculiar organic remains, and was marked by distinctness of physical fea- tures, lithological structure, and order of superposition, it was well entitled to be considered a separate system. It was not therefore enough that, in my efforts to deve- lope them, I had termed these deposits, in their natural descending order, the ‘“‘ Ludlow,” ‘‘ Wenlock,” ‘‘ Caradoc,” and ‘‘Llandeilo” formations; without some collecttve name, no general view could be carried out, nor their relations to the whole series of deposits established. For example, the group could not be defined ‘“Transition Rocks,” because nearly every modern author had so extended the meaning of this term, as to embrace in it all the deposits, from the carboniferous series inclusive, down to the oldest slaty rocks in which organic remains cease to be percep- tible ; whereas the object I had specially in view was, to point out the existence of in- termediate rocks of great thickness, essentially different both in structure and organic re- mains from the carboniferous strata. In early communications to the Geological Society, adopting a provisional name, I called these rocks “‘ fossiliferous greywacke ” ; but this term was deemed objectionable, there being few beds in the group which can be recog: nised as the “‘grauwacke”’ of German mineralogists—while there are fossiliferous 1 Originating with the Right Honourable Frankland Lewis and his son Mr. George Lewis, this requisition was soon subscribed by many resident nobility and gentry through the very friendly exertions of Lord Clive. (See List of Subscribers. ) INTRODUCTION. 7 rocks having distinctly that mineral character, both above and below those which I describe. | | A. geographical term was finally adopted, derived from the Silures, whose power extended over the region where these rocks are best displayed, and the name of whose illustrious. chief, Caradoc (Caractacus), has been transmitted to us in a bold range of hills, composed of one of the most important formations of the system to be de- scribed. The term was no~sooner proposed than sanctioned by geologists, both at home and abroad, as involving no theory, and as simply expressing the fact, that in the ‘‘ Silurian region,” a.complete succession of fossiliferous strata 1s interpolated between the Old Red Sandstone and the oldest slaty rocks. M: Elie de Beaumont, for example, warmly encouraged me to use this name, and with his coadjutor M. Dufrénoy has since materially contributed to give it currency on the Continent. Soon afterwards M. Boué and M. de Verneuil announced the diffusion of ‘‘ Silurian” rocks in Servia and the adjacent parts of Turkey in Europe, while our countrymen Hamilton and Strickland extended their range to the Thracian Bosphorus. More recently, M. Forchhammer of Copenhagen has visited the ‘‘ Silurian region ”’ to endeavour to recognize in it the rocks of Scandinavia ; and even whilst I write, MM. D’ © Omalius D’Halloy and Dumont are exploring it to establish a parallel between its de- posits and those of Belgium. Lastly, I may state, that M. de Boblaye has honoured me by offering to translate this work into the French language. Shortly after I proposed the name ‘‘ Silurian,” one or two European tracts were, indeed, pointed out as resembling that which I had selected as a type. One of the most remarkable is on the southern frontier of the Ardennes, where three forma- tions were recognised by Dr. Buckland and Mr. Greenough as occupying the same geo- logical position as in England and Wales; namely, between the carboniferous deposits and the older slaty rocks. That similar deposits exist in many parts of Europe is evident from the works of Strangways, Brongniart, Von Buch, Hisinger, Dalman, Keilhau, and other writers, as well as from the fossils found in Norway, Sweden, Russia, Poland, Germany and France ; though patient comparisons must be instituted before the peculiar relations of the Si- lurian Rocks of those countries can be established’, Their spread through distant regions will be again brought under consideration, in the concluding view of the general distribution of organic remains. In the mean time it 1 I cannot attempt to enumerate the names of all the foreign authors who have written on Transition Rocks, though many of those who treat of the Organic Remains are alluded to hereafter. See Part II. Judging from the maps of Hisinger and Keilhau, I presume that both Upper and Lower Silurian Rocks exist in several di- stricts of Sweden and Norway. It would appear that I may have been led into an error (p. 169 note) in sup- posing that the Old Red Sandstone occurs in these regions. I hope, however, at some future day, to examine personally the older rocks of Scandinavia and Russia, and to show to what extent they agree with those of our own country. 8 INTRODUCTION. may be stated, that such deposits unquestionably exist in North America, not only as inferred from the publications of our countrymen Bigsby and Weaver, but also from the works of several American authors who have described organic remains (Dekay, Green, &c.), as well as from the letters of Mr. Featherstonhaugh and Professor Rogers. And although I have not yet seen a sufficient number of fossils to enable me to enter into details, the identity of certain species of trilobites, common to that continent and Great Britain, sufficiently sustains the accuracy of the inference. It is, indeed, probable that the Silurian strata are distributed throughout that quarter of the globe, since Mr. Charles Darwin has recently brought home from the Falkland Islands masses of rock, charged with fossils which can with difficulty be distinguished from specimens of the Caradoc sandstone,—while the existence of other Silurian Rocks in Southern Africa has been established by the evidence of organic remains collected by Dr. Smith, and first transmitted to me by Sir John Herschel. We have, therefore, every reason to believe, that although the eotipiell order of the foreign deposits of this age has not yet been pointed out, a little more labour will enable us to place them in parallel with our own. But to return to England,—soon after I issued my first prospectus, Professor Sedg- wick assigned to the older and contiguous rocks of Wales the name of Cambrian ; and the reason is obvious ; for the strata so designated are not only conterminous with the Silurian System, but are in several parts seen to rise from beneath its lowest beds, and fairly to unite with them. These names are not, however, propounded as immutable ; they are simply offered as the best means we possess of clearly defining the objects to be attained. To show that these systems, like other large groups of strata in Great Britain, occu- pied their true positions in the sea cliffs, both in relation to each other, and to the younger deposits, I terminated my survey, by following them into Pembrokeshire,— proving, that after a course of one hundred and sixty miles, they preserved the same relation to each other and to the overlying deposits, as in Shropshire and Here- fordshire. Professor Sedgwick will complete this portion of the task, by explaining how the two systems range to the coast of North Wales, and how they are there related to the younger formations. In tracing them to distant parts, the reader must not expect to find the Silurian rocks preserving an uniform lithological character, or conforming precisely through- out large spaces to the prevailing mineral types of the region described. This remark applies not merely to other countries of Europe, but even to distant parts of Britain: thus, although the calcareous flags of Llandeilo with their accompanying schists are considered to form the base of the Silurian System, their place is some- times taken, often indeed they are underlaid, by sandstones of considerable thickness. Again, besides the frequent absence of beds of limestone in the Ludlow and Wen- lock formations above alluded to, those deposits do not preserve the same lithological INTRODUCTION. g characters over wide tracts, their colour and composition in parts of Caermarthenshire and Pembrokeshire, and also at Tortworth, being very different from those of the same rocks in Shropshire and Herefordshire. And thus the lesson which has been already taught us by an examination of the younger deposits is repeated,—that the zoological contents of rocks, when coupled with their order of superposition, are the only safe criteria of their age. By such proofs we are enabled to distinguish the Silurian de- posits from all others previously described, and through every lithological change we can thereby separate the system into upper and lower divisions. Quitting the Silurian rocks, and taking an ascending prospect, I may observe, that although the stratigraphical position of the Old Red Sandstone and its general rela- tions, both in England and Scotland, were well known, no complete account of its range, succession, and zoological contents, in Herefordshire and the adjacent counties, had yet appeared, though it there forms one of the largest of the stratified British groups’. Perceiving that besides this great thickness, the Old Red Sandstone had an individuality of mineral character, and peculiar organic remains, I ventured for the first time to designate it a system. This step was taken, not only to mark distinctly the vastness of the strata by which the Silurian deposits are separated from those of the carboniferous sera, but also to indicate at one glance, that the coal measures of our country are in- cluded between two great red coloured systems of rock—the New Red Sandstone above, the Old Red Sandstone below. Had my labours terminated at this point, the Silurian Rocks, and their immediate relations to the overlying and underlying deposits, might have been long ago deve- loped ; but I felt that unless the structure of the whole region in question was made known, the map would have been imperfect, and the work would have borne an un- finished character. I therefore resolved to give sketches of all the coal fields included in the area examined, and further to explain their relations to the surrounding deposits. In adopting this resolution, however, I could scarcely estimate the additional exertions required ; for, with the exception of the basins of the Forest of Dean, and of South Wales, none of these coal tracts, so important in the mineral economy of the nation, had been described. But these subjects did not exclusively engross my attention. To render their history complete, it was necessary to. examine minutely all the rocks of igneous or volcanic origin, which are interlaminated with, or penetrate the strata at so many points, as well as to follow out the lines of elevation and dislocation. Further, to arrive at clear 1 The highest mountain in South Wales, called the “‘ Fans’ or points of Brecon, from its double summit, is 2862 feet above the sea, and is entirely composed of nearly horizontal beds of Old Red Sandstone. Through an error of the press, (p. 170) this mountain is stated to be 2500 feet high. The height of the Caermarthen Fans is accurately given as 2590 feet. Both these mountains are seen in the view facing p. 346, and the heights of both are correctly marked in that lithograph and on the map. | A * 10 INTRODUCTION. deductions, it was indispensable that all the overlying formations should be examined’ and their boundaries laid down upon the map. In searching the younger deposits I learnt, that the New Red System was separable into distinct formations, one of the uppermost being found to contain a band of sand- stone with peculiar fossils. Though not previously noted, this rock most clearly re- presents the sandstone of the ‘‘ keuper”’ or ‘‘ marnes irrisées ;”” while the central masses of sandstone, both by geological position and the plants they contain, are shown to occupy the place of the ‘‘ bunter sandstein”’ or ‘‘ gres bigarré”’ of foreign geologists. Finally, I ascertained, that within the area of the Silurian region there were na- tural sections, exposing passages throughout the whole series, and thus connecting all the formations from the oolitic to the slaty Cambrian rocks; a most remarkable fact, ~ and one perhaps almost without parallel in any European district of like extent. I need hardly say, that these numerous branches of the subject have caused a much longer examination than was originally contemplated and have considerably retarded the appearance of these volumes. Geologists, indeed, require no apology for the delay, as they well know that the illustrations of such a work could not have been rapidly prepared ; but from those friends who have not made our science their pursuit, and yet have countenanced my efforts, a larger measure of indulgence is claimed. With the aid, however, of the map, the numerous coloured sections, and pictorial views, it is hoped that this class of readers will not encounter many serious difficulties. As owners of the soil, I hope they may derive some use, not only from the efforts I have made to indicate where coal may be advantageously sought for, but from those which demonstrate where it never can be found ; while a knowledge of the true nature of the sub-strata cannot fail to be of value to the agriculturist. In deciphering the history of these rocks, 1 have worked from the upper or known formations to the lower or unknown, and the reader will therefore be led through a descending geological series. The younger stratified deposits which flank the Silurian territory on the east and north will be first described, and then the inferior sedimentary masses; while the rocks of volcanic origin, and the effects produced by their intrusion amid the strata, will be pointed out in each district in which the order of the beds has been previously established. After being thus carried back to remote periods, during which the order of the strata has often been deranged by great dislocations and volcanic eruptions, the reader’s atten- tion will be called to the various sorts of superficial detritus of the region, which being formed out of all the solid formations, could not be intelligibly explained without a pre- vious account of the rocks from which it has been derived. In this branch of our subject, the reasons for pursuing a descending order of inquiry no longer existing, the historical method is adopted. Beginning, therefore, with the consideration of the earliest deposited loose materials, the student will have successively placed before him each newer accumulation of gravel or sand, whether entirely marine, or formed during INTRODUCTION, 11 the transition from a submarine condition, into the era when the newly-raised surface was first occupied by lakes and broad rivers. He will, in short, be conducted, step by step, from the time when large portions of our island were beneath the sea, to the con- sideration of the deposits which are in actual progress of formation above it ; and thus he will embrace in one view the passage from the vast geological epochs mtg the com- paratively brief period of history. The first part of the work, including the descriptive geology of the region, will then be terminated, by a review of some striking results of the present inquiry. The second part is exclusively devoted to Zoology, and contains the evidences on which many of the principal conclusions are founded; being a description of all the fossils of the Old Red and Silurian Rocks, prefaced by a general view of the distribution of animal life during the accumulation of those ancient strata. Geologists will determine whether the results now offered to them are worthy of their approval. Ifit be acknowledged, that no sound general views of the early periods of the earth’s history can be obtained, without a close investigation of the beds which connect the sedimentary deposits previously known with the oldest stratified rocks, then I may venture to hope, that the endeavour to clear up this difficult subject, will be considered a step, however small, in the foundation of the science. We already know, that certain deposits with their organic remains, may be expected to show themselves (though sometimes under different aspects) in distant lands. Thus the tertiary and secondary strata have been identified over remote parts ; while our own island is remarkable for having afforded in great measure the original types of the secondary age which directed that investigation. It appears highly pro- bable, nay, it is even to a great extent already ascertained, that phenomena of the same kind prevail with respect to the system described in this volume ; and that Siluria, with its accumulations of remote antiquity teeming with organic remains, presents a table made up of some of the earlier and hitherto undeciphered pages, which the history of the earth in other countries offers to our study. But the Silurian, though ancient, are not, as before stated, the most ancient fossili- ferous strata. They are in truth but the upper portion of a succession of early de- posits which it may hereafter be found necessary to describe under one comprehensive name. For this purpose I venture to suggest the term ‘‘ Protozoic Rocks,” thereby to imply the first or lowest formations in which animals or vegetables appear. That there is a limit in the descending scale of formations, beneath which no traces of life have been discovered, is now pretty generally recognised ; and looking merely to this fact, geologists may agree to use the word “ Protozoic,” however they may differ in their interpretation of the phenomenon. . One class of observers believe, that life did not exist when the earliest deposits took place. They hold that the oldest crystalline strata (ancient gneiss, mica schist, &c.) were formed during a period of great heat: and the astronomer seems to strengthen 12 INTRODUCTION. this opinion, by showing that the planet must have been in a state of total or partial fusion when it assumed its present shape. Such reasoners are led to suppose, that the — earliest accumulations occurred under conditions which forbade the possibility of any vital organization; and they are further strengthened in their creed, when on exa- mining the innermost folds of the earth’s covering which have been extruded, they find in them no vestiges of life. They conclude therefore, that it was only after a long time, and when the surface had to a certain extent been cooled down by succeeding changes and the addition of fresh materials, that animals and vegetables were called into existence. | E Other geologists contend, that as yet we gaze but dimly into the obscure vista of these early periods ; and that even if organized beings did live when the first crystalline rocks were formed, we cannot now hope to discover evident traces of their existence, owing to the great metamorphoses which subsequent agencies have produced in these masses,—metamorphoses which may be well supposed to have obliterated all traces of primeval creation. . indi | Without here attempting to decide this question, I would merely observe, that the term ‘‘ Protozoic,” as above interpreted, may be used by the maintainers of either doctrine. | | tod | ce | In conclusion, I repeat that my chief object is to develope the upper portion of this vast series ;—its lower divisions belong to the task which has fortunately fallen to Pro- fessor Sedgwick. | | CHAPTER II. OOLITIC SYSTEM. Inferior Oolite.—Lias.— Outliers of Lias. ORIGINALLY I had no intention of describing any rocks of so recent an age as the Oolite and Lias. The work was to have commenced with an account of the New Red Sandstone, as the youngest secondary deposit in the vicinity of any portion of the “Silurian System.” The discovery, however, of a great outlier of Lias in the North of Shropshire and adjacent part of Cheshire, where the existence of that forma- tion had never been even suspected, has induced me to extend the plan, and to preface an account of that large insulated mass, by a few observations on the relations and structure of the Inferior Oolite of the Cotteswold Hills, and of the Lias of the Vale of Worcester and Gloucester ; more particularly with the view of showing how the latter passes down into the New Red Sandstone’. In general terms, the Oolitic Series may be described as a great and diversified group of limestones, sandstones, grits, and clays, ranging across our island from Dorset-_ shire on the south-west to Yorkshire on the north-east. The central members of this sroup occupy the high districts of Oxfordshire and Gloucestershire, which form the eastern limits of the annexed map. In this district Mr. Lonsdale has worked out with ereat assiduity the relative position of the different members of the system, rectifying an important error in their classification, and laying down their outlines to a great extent on the maps of the Ordnance Survey’. 1 Smith’s Strata Identified. It was in the oolitic series of the adjacent counties, that Smith established the great principle of identifying the English strata by their imbedded organic remains. For information respecting the Oolitic Series, see Outlines of the Geology of England and Wales, by Conybeare and W. Phillips ; Geology of Yorkshire, 1st Vol., by Professor Phillips. Also various Memoirs in the Transactions of the Geological Society of London, by Messrs. Buckland, De la Beche, Lonsdale, and Murchison. 2 In pursuing his examination of the range of the Oolites, Mr. Lonsdale was the first to. discover the true geological position of the Stonesfield Slates, so long known to collectors by the beauty and number of their organic remains. ‘These Tilestones were formerly supposed to overlie the Great or Bath Oolite, but Mr. Lonsdale has shown that in the Cotteswold Range they form the bottom of that rock. Having myself ex- amined a portion of this district in detail, I may be allowed to State my belief that no geologist could so clearly and systematically have rectified this important error of previous observers in the order of these beds, as Mr. Lonsdale; for no one had so closely studied their relations in the Bath district, whence as a type or base he extended his inquiries. B bin, 14 INFERIOR OOLITE. Rising from beneath the central members of the system, the Inferior Oolite and Lias appear in great force along the escarpments of the Cotteswold Hills. As the beds of these two formations have a general inclination to the east and south-east, at angles varying from 5° to 12°, it is evident that, in crossing from the Cotteswold Hills to the Severn, the strata of each group will. be seen to emerge from beneath those which have been deposited over them. In this way we make our first transverse section. The following description applies, therefore, to such strata as are found in “ de- scending order,” upon any straight line drawn from the escarpment of the Cotteswolds to the banks of the Severn. See coloured section Pl. 29. fig. 1. and this wood-cut. (West.) | (East.) 1. New Red -. Red and green Marl. d. Upper Lias. ita h: “ Gryphite Grits.” Sandstone. Lz. Sandstone and Marl. Lias.J & Marlstone. Oolite 6. Cheltenham Building-stone. "| f. Lower Lias Shale. ’ Le. “Pea Grit,” g. Limestone of the Lower Lias Shale. Inferior Oolite. The rocks composing this formation in the Cotteswold Hills are all more or less calcareous. ‘They rise to the west, from beneath certain clays and flaglike beds (Stonesfield Slate), and occupying a thickness of about. 150 feet, are divisible into three parts. (a. of section.) The uppermost is a brown calcareous grit, of a very coarse aspect, owing to the number of shells it contains, among which Gryphea Cymbium, Lima proboscidea, Trigonia costata, and Pholadomya ambigua are the most abundant. This ‘‘ Gryphite grit’ caps the hills, and is extracted for the use of the roads’. (b. of section.) The central division is much the thickest, and may be subdivided into three parts. 1st. Upper Ragstone, and thin-bedded Oolite. 2nd. A fine-grained, light-coloured Oolite, the Cheltenham building-stone, which varies from thirty to forty feet in thickness, and when quarried under ground is dressed with facility?. It is 1 I named this stratum ‘‘ Gryphite grit,’ from the prevalence of the “ Gryphea Cymbium.” This name and that of Pea grit (p. 12) are local terms, applicable only to the structure of the Upper and Lower strata of the Inferior Oolite of Gloucestershire. (See Sketch of the Geology of Cheltenham, 1834. J. Murray.) 2 In general, the Oolitic freestones, from whatever part of the system they are derived, on being exposed to the atmosphere, lose much of that moisture which they naturally possess under ground, and become much harder. The quarries of Ketton, in Northamptonshire, which are in the Great Oolite, yield, like those of Chel- tenham, blocks of very large dimensions. ‘These blocks are easily cut with the saw on being first extracted, but become rapidly harder on exposure to the atmosphere, and when struck with a hammer clink like a piece of metal. INFERIOR OOLITE. 15 undistinguishable in lithological character from the freestone of Bath (Great Oolite), although that rock is of more recent date’. 3rd. Lower Ragstone. Very fine-grained, hard Oolite; some beds largely quarried as trough- stones. The Oolitic structure becomes coarser downwards, and passes into a rough concretionary rock at the base of the formation. - The prevailing fossils of this central division are Clypeus sinuatus, Terebratula fimbria, T. glo- bata, and 7. perovalis. (c. of section.) The lowest member of the Inferior Oolite hasa remarkable aspect. It is of a rusty brown colour, and is in great part made up of small flat concretions, from a quarter to half an inch in diameter, which give to the stone, on first inspection, the appearance of a Nummulite rock. It is called “ Pea Grit ’’ by the country people, and is a useful stone, when employed for gate-posts and other rough work. Coralline bodies and Pentacrinites are spread over the sandy iron-shot faces of the beds, and veins of crystallized carbonate of lime are of frequent occurrence throughout the strata. The organic remains of the formation in these hills are very numerous, the following, collected by myself, being probably but a small portion of those which will hereafter be found. Fossils of the Inferior Oolite of the Cotteswold Hills’. Ammonites Brownitt. M. C. t. 263. and por- Modiola plicata. M. C. t. 248. tions of other species of Ammonites. Mya calciformis. Phill. t. 11. f. 3. — corrugatus. M.C.t. 451. f. 3. Natica adducta. Phill. t. 11. f. 35. — elegans? M.C.t. 94. Ostrea acuminata. M. C. t. 135. Marshiit. M.C.t. 48. solitaria. M. C.t. 468. f. 1. Belemnites (portion of). Berenicea diluviana. Lamouroux, Expos. Mé- thod. t.86.f.12 & 14. M.C.t. 424. Pentacrinites. Cirrus carinatus. M. C. t. 429. Pholadomya ambigua. M. C. t. 227. Clypeus sinuatus. Parkinson, Organ. Rem. Fidicula. M. C. t. 225. VOlspilie tower tenl. ———— obtusa. M. C. t. 197. f. 2. Corals (of several species). Pecten. Species undetermined. Gervillia Species same as in Normandy. Plicatula. Species undetermined. Gryphea Cymbium. Lamarck ; see Deshayes, Plagiostoma cardiforme. M. C. t. 113. f. 3. Coquilles Caractérist. des Terrains, pl. 12. giganteum. M.C. t. 77. (ep Lb ee ——_— —— Parkinsonii. M. C. t. 307. Tsocardia concentrica. M. C. t. 491. f. 1. —- punctatum. M.C.t.113.f.1&2. rostrata. M. C.t. 295. f. 3. Terebratula emarginata. M.C. t. 435. f, 6. Modiola gibhosa. M. C. t. 211. f. 3. ———-— fimbria. M. C. t. 326. 1 See note on Mr. Lonsdale’s discoveries, supra, p. 13. 2 The greater number of the organic remains in this list have been named and figured by Mr. J. De C. Sowerby, in his work “Mineral Conchology.”’ The letters M. C. refer the student to that book, which forms an essential part of every Geological Library. Some of the fossils are to be found in Phillips's “ Geology of York- shire.” BQ 16 UPPER LIAS. Terebratula globata. M. C. t. 436. f. 1. Trigonia costata. M.C.t. 85. media. M.C.t. 83. f. 7. — striata. M.C. t. 237.f.1,2&3. ————- ohsoleta. M. C. t. 83. Unio abductus. Phill. pl. 11. fig. 42. perovalis. M.C.+t.436.f.2&3. Should the observer extend his range to the south-west, he may trace similar strata, containing many of the same species of fossils, from Gloucestershire through Somerset- shire, to the coast cliffs at Bridport, Dorsetshire, where he will see the beds laid bare, dipping under younger formations, and resting upon the vas, as in the Cotteswold Hills. In like manner, if he follow these beds north-eastward, he will find their re- presentatives occupying similar positions in the Oolitic escarpment of the counties of Oxford, Northampton, Rutland, and Lincolnshire, and thence extending to the high and rugged cliffs between Scarborough and Whitby in Yorkshire’. The Lias. The Lias, or base of the Oolitic System, forms the subsoil of the whole of the Vale of Gloucester, extending from the Cotteswold Hills to the Severn. Like the Inferior Oolite, this formation may be followed on the south-west to Lyme Regis* in Dor- setshire, and on the north-east to Whitby in Yorkshire. Near the latter place it is more fully developed than in any other part of the kingdom, and has there been divided by Professor Phillips into three parts. A fourfold division, however, is practicable in Gloucestershire and Worcestershire, viz. 1. Upper Lias Shale ;—(the Alum Shale of Yorkshire.) 2. Marlstone. 3. Lower Inas Shale. 4. LInmestone of the Lower Lias Shale. The Upper Lias Shale (d. of section, p. 11.) consists of a bluish clay, containing occa- sionally nodules, or spherical concretions of dark argillaceous limestone, called in York- shire and elsewhere ‘‘cement stones.” This subgroup ranges along the escarpment of the Cotteswold Hills, and may be seen on the sides of many of the roads where they begin to descend from the hills into the valley of the Severn. In this stratum I have observed the following organic remains. 1 See the Geological Map of England and Wales, by Mr. Greenough. ‘Those who desire to obtain a full knowledge of the different localities in which the same species of fossils have been found, must consult the tables in the ‘‘ Geological Manual” of De la Beche (8rd edit. 1833), and the Outlines of the Geology of England and Wales, by Conybeare and Phillips, 1822. 2 Every fossilist should visit the collection of Miss Mary Anning, at Lyme Regis, who, by her discoveries, has so materially contributed to our acquaintance with the organic remains of the Las, especially in the class of those gigantic reptiles which characterize the formation. MARLSTONE. 17 Ammonites annulatus. M. C, t. 222. Gervillia. New species. - undulatus. Smith, Strat. System, Inoceramus dubius. M. C. t. 584. p. 114. Marlstone, Plate, f.3. M. C. t. 254. Lucina ? dele Oo ae Modiola. New species? — Walcottti. M. C.t. 106. Nautilus. Arca, or Cucullea? Fragments. Nucula. New species. Belemnites acutus. M. C. t. 590. Pholadomya. — penicillatus. M.C.+t.590.f.5 &6. Plicatula spinosa. M. C. t. 245. —-————— tubularis. Phill. t. 11. f. 27. Trochus bisectus. Phill. t. 11. f. 27. The presence of this zone of clay, which in some places must have a thickness of sixty or seventy feet, is marked by the outburst of water, either in the form of springs, or indicated by rushes and wet ground. It forms, in fact, the retentive support of all the rain-water which percolates the overlying porous strata of the Inferior Oolite, and thus gives rise to the river Chelt ; to the Seven Springs, or chief sources of the Thames ; to the springs which supply the Cheltenham reservoir; to those which in ancient times filled the Roman baths near Whitcomb ; and to all the streamlets which, descending from the Cotteswold Hills, are tributaries of the Severn. The Marlstone (e. of section) is made up of alternating layers of yellow and blue marly clays and sands, fox-coloured sandstone, sometimes calcareous, and beds of impure limestone. The most prevailing fossils are— Avicula inequivalvis. M. C. t. 244. f. 2. Pecten equivalvis. M. C. t. 136. f. 1. Belemnites penicillatus. M.C.t.590.£.5 &6. Terebratula concinna. M. C. t. 83. f. 6. Cardium truncatum. M. C. t. 553. f. 3. ——_——— tetrahedra. M.C, t. 83. f. 4. Gryphea gigantea. M.C. t. 391. Numerous ravines, by which the western sides of the Cotteswold Hills are furrowed, expose this subdivision underlying the upper shale. It is also displayed in many de- tached hills or outliers from the main ridge, as in Church Down, Robin Hood Hill, Bat- tledown Hill near Cheltenham, Oxenton, and Bredon Hills. Outhers of Marlstone. The hill of Church Down', which from its insulated position presents so striking an object, affords one of those examples of denudation which are frequent in the Vale of Worcester and Gloucester. The quarries upon the tabular summit are covered with a few feet of yellowish sandy loam, containing spheroidal concretions of hard calcareous grit, called ‘‘men’s heads” by the workmen. These nodules resemble those which mark 1 Pronounced Chosen by the inhabitants. 18 LOWER LIAS SHALE. the lines of stratification in the coast cliffs near Bridport, Dorsetshire ; and others which I have described-as occupying nearly the same geological position in the Hebrides’: Beneath this sandy loam, the quarries in work, (1831,) exhibited the following beds of | the Marlstone. : | fe. Sin 1. Lightish yellow micaceous sandstone full of Belemnites................4-% 4 0 2. “ Pot-ears.”” Bluish gray calcareous grit, quarried for troughs. ............. 1 6 3. © Pendle.”’ Brownish hard calc grit, jointed and fissured. ...... EEN rts 0 10 4. Wayboard of clay, with some fossils ....... oh 1p ler GG WP) Dis: < Pics fae Og 5, “ Leathering-bed.’”? Thick-bedded very hard micaceous marlstone, of greenish brown colour, charged with fossils, of which Pecten equivalvis and Belemnites abbreviatus are tle most. abundant: #4 Mecpsks dette, Eee cafe mee tree eae a et ed ees 5 O 6. * Best double Blue.’’ Hardest and best road-stone, weathers to a brown colour .... 1 3 7. “Lowest Blue.”” A blue calcareous grit, partially discoloured by the decomposition of | ONS ens ee er ee a Re ANS 9 RO et Re ep aD See ee we eyes 1 5 Beneath this bed the water stands upon the clay of the lower Lias, which occupies the sloping sides of the hills. A line drawn to the east, in the prolongation of the surfaces of these beds, would precisely fall upon that part of the escarpment of the Cotteswolds where the strata of the Marlstone, containing similar organic remains, occupy their regular place in the series. It is therefore evident, that the intervening valley has been hollowed out subsequently to the formation of the Lias and the Oolite ; or, in other words, that there was a period when the strata of the Cotteswolds extended in continuity as far as Church Down Hill. The same explanation applies to Oxenton, Bredon, and all the other outlying masses of the Vales of Gloucester and Worcester. (See Map.) The Lower Lias Shale, (f. of section,) or great mass of the formation, occupies the greater portion of the Vale of Gloucester and Evesham. This Shale, resembling that of Dorset and the lower Shale of Yorkshire, is a dark- coloured calcareo-argillaceous and finely laminated deposit, containing occasionally cement stones or concretions similar to those described in the Upper Lias. Among the fossils which characterize it in the eastern part of the Vale are Ammonites Cheltiensis; and 5 or 6 other Belemnites elongatus. Miller, Geol. Trans. Ammonites of undescribed species, some vol. ii. p. 60. pl. 7. f. 6, 7, & 8. very small. Crenatula ventricosa. M. C. t. 443. Astacus glaber. N.s. Phillips. Cucullea elongata. M. C. t. 447. Avicula inequivalvis. M. C. t. 244. Gryphea incurva. Parkinson, Org. Rem. vol. Belemnites abbreviatus. M.C.t.590.f.2,3, &9. itcies Genel toy, caltstene 1 Transactions of the Geological Society, New Series, vol. il. p. 353. LOWER LIAS. 19 Gryphea obliquata. M.C. t. 112. Spirifer. Hippopodium ponderosum. M. C. t. 250. Turritella muricata? M.C. t. 499. Lima antiquata. M. C. t. 214. Unio ? Pecten. 'Three undescribed species. en 7 Vertebre of the Ichthyosa ha ] Pentacrinites scalaris. Goldfuss. PCCRME ME HaveaarsO” Deen Serpula. round The Ammonite which I have named after the town of Cheltenham A. Cheltiensis, is found also in the Lias of Lyme Regis in Dorset. It is represented in the following wood- cut (a.), together with the two most characteristic bivalve shells, Gryphea incurva (0.) and G. obliquata (c.). | SSS y) zie FI) eZ i i SS 1/1 SSA SSS The cement stones frequently contain Belemnites, and Ammonites Cheltiensis, occa- sionally covered with an iridescent nacre. Many of the layers of this shale are highly charged with iron pyrites (sulphuret of iron), and when the fossil remains are coated with this mineral, it generally gives to their surface that bright metallic lustre seen upon many of the Ammonites. Inmestone of the Lower Laas Shale, (g. of section.) The right bank of the Severn in the environs of Gloucester is occupied by several plateaus of Lias, which in some points of their escarpment, as at the western part of Highnam Court, present good sections of the passage of the lowest beds of the formation into the marls of the New Red Sandstone. These consist of laminated shale, containing a few thin beds of calcareous flagstone, the whole dipping to the east and south. In following the Lower Lias thence through Gloucestershire and Worcestershire, its line of junction with the marls of the New Red Sandstone is not confined to the left bank of the Severn as marked upon previous geological maps!. The Lower Lias also occupies the hills between Deerhurst and Tewkesbury, and appearing on the right bank of the Severn, is quarried at Forthampton Court and at Bushley, Worcestershire ; and still farther to the north it appears in the insulated hill of Longdon Heath near Upton. This is the last outlier on the right bank of the river, the formation thenceforth following 1 For new outline west of Gloucester by Corsewood Hill, to Combe Hill on the left bank of the river, see the Map annexed to this work. 20 LOWER LIAS. the left bank from Shothonger Common to Brockeridge Common, three miles north of Tewkesbury, whence it takes a straight course to the north-east by Boughton Hill and Pirton to Norton, four miles south-east of Worcester. In describing the structure and contents of the Lower Lias, and its junction with the marls of the New Red Sand- stone along the line just mentioned, we may particularly notice a section at Combe Hill, six miles north of Gloucester, as exhibiting a perfect and conformable transition from the one system into the other. In the descending order we first perceive about 12 thin courses of dark-coloured calcareous flagstones, which are extracted for roads, paving, building, and burning to lime. These courses vary in thickness from 1 to 3 inches, and are separated from each other by stiff marl: the two lowermost bands, known locally as the “‘ Rattler’ and the ‘‘ Bottom bed,” are alone burnt for lime. The surface of the flagstones is frequently covered with numerous fine and delicate species of Echini; and bones and vertebre of Saurian animals have also been found. These beds are underlaid by sandy pyritiferous shale, graduating downwards into cream- coloured marl, succeeded by shivery, finely laminated, black shale, highly charged with iron pyrites and small crystals of selenite, and containing a few thin courses of whitish sandstone. The predominant fossils are Ammonites planorbis. M. C. t. 448." Modiola minima. M. C. t. 210. Modiola Hillana. M. C. t. 212. Ostrea. Small unpublished species very abundant. Beneath these beds of flagstone, shale, and sandstone, there is a passage, through lightish blue and grey marl, into the green and red marls, which form the upper limits of the New Red Sandstone system; the beds dipping at an angle of about 15° to the south-east. The calcareous bands are known locally under the name of “ clay- stones’,” and they mark the base of the Lower Lias in its course through Gloucester- shire and Worcestershire. When well exposed, they are always seen to graduate down- wards, through finely laminated black shale, into the same whitish sandstone observed at Combe Hill. Such relations appear in the promontory of Bushley, on the left bank of the Severn, at Corsewood Hill, two miles west of the Haw Bridge; on the sides of the high road from Tewkesbury to Ledbury ; and at Forthampton Court; the small Ostrea, and Ammonites Planorbis, being the prevailing fossils. An outlier called Longdon Heath, near Upton, has been during many years quarried for limestone, 1 Remains of Saurian animals have occasionally been found in the Vale of Gloucester, both in those beds and in the Clays above, but as none of these specimens have fallen under my own observation, I cannot state to what species they belong. 2 This “ Claystone” of the Lias was formerly employed as the only road-stone; but the facilities afforded by water-carriage and the tram-roads, are now so great, that nearly all the high roads of the Vale are repaired with limestone brought from Bristol, which is termed by geologists mountain or carboniferous limestone. Being much more free from earthy matter, and more crystalline than the claystone, it forms a more durable road, LOWER LIAS. 2] of which six beds are used, and known by the names of “'Top,”’ “ Black,”’ ** Tile,”’ “* Poacher,”’ “‘ Peaver,” and “ Bottom.’ The Poacher is an irregular course appearing and disappearing; the <‘ Bottom ”’ is the best stone, and is seven inches thick. The strata on the north-west end of the hill dip east-south-east 6°, but where they crop out the inclination increases to 12° and 15°. On the higher parts of the hill the dip is north-east, and in its east-north-eastern face there are quarries twenty feet deep, where the dip is west-south-west. This outlier and the range of Lias by Bushley are, for the most part, covered with drifted superficial matter, composed of red clay, or gravel and sand, which generally conceals the subsoil in this part of Worcestershire. At Brockeridge Common, north of Tewkesbury, the same strata are very well expased, the work- men reckoning five principal calcareous beds, including one of Z%lestone. 'These are overlaid by hard layers, and underlaid by slaty clay, which towards the base becomes sandy, and finally passes into the thin-bedded white sandstone to be described in the next chapter. The lower Lias of Brock- eridge contains the characteristic fossils found at other places, viz. abundance of the small Modiole and Ostrese, together with Ammonites Planorbis, Plagiostoma gigantewm, and other fossils. The ordinary dip is about 10° south-east and east-south-east ; but in one place the lowest bed rises up at an angle of 25°. As the lower Lias occupies the highest ground in the environs of Tewkesbury, it is there dignified by the title of the “hill rock” in contradistinction to the red marl, which is usually in the lower ground. The same lithological and zoological characters are preserved along the straight ridge of the lower Lias, extending from Brockeridge Common to Boughton Hill and Pirton. The continuation of the lower Lias from Pirton and Norton, near Worcester, into Warwickshire has been carefully traced by Mr. Strickland, jun., for many miles, and the boundaries have been laid down by him upon the Ordnance Map, including several large promontories of Lias hitherto unnoticed. He has also discovered that the New Red Sandstone has been protruded through the Lias along a line of fault near Crop- thorn. It never was my intention to trace the course of the Lias into Warwickshire, and I have attempted to describe its characters in the Vale of Gloucester and Worcester, merely to point out the peculiarities of lithological structure and zoological contents, where the lower members pass downwards into the New Red Sandstone’. Such are the deposits which may be observed in crossing the Vale of Gloucester and Worcester from east to west. They are all rocks of sedimentary origin, and are made up of a prodigious number of beds or layers, each formation possessing an individuality of mineral character and organic remains ; and as we descend in the series, we find the remains of animals differing from those which had been deposited in the beds of earlier age. These submarine accumulations have, however, undergone great alterations since the period of their original deposit, either by denudation during their rise from beneath the sea, or by disintegration since they have been exposed to the atmosphere. They have likewise been greatly affected by disturbing agents, some remarkable proofs of 1 The curious and important subject of the origin of the Cheltenham and other mineral waters of the Vale of the Severn, will be entered upon, as soon as we have described those rocks in which they take their rise. Cc 22 LIAS IN SHROPSHIRE AND CHESHIRE. which occur in the Cotteswold Hills, where the strata of Inferior Oolite dip in opposite directions, and at high angles of inclination. Detailed accounts, however, of these phenomena do not fall within the province of this work, and a correct acquaintance with them can be only obtained by long and patient research. On an Outlier of Lias in the North of Shropshire and South of Cheshire. Relying upon the general belief of English geologists, that the low country of North Salop and the South of Cheshire was occupied exclusively by the New Red Sandstone or detritus covering that formation, I did not, during the first three years of survey of the adjoining country, extend my researches beyond the Hawkstone and Hodnet Hills, lying about fifteen miles to the north and north-north-east of Shrewsbury. In October, 1834, I accidentally learnt that sinkings in search of coal, had been prosecuted to some extent in the district between Whitchurch and Market Drayton. On examining the district I was soon convinced that the black shale, supposed by the inhabitants to be coal shale, was nothing more than Lias, as was proved by an abundance of fossils ; and that far from being confined to one spot, this formation, though much obscured by gravel and clay, could be detected over a considerable area. I also found that this mass of Lias was deposited in a basin, of shape more or less elliptical, from beneath which the New Red Sandstone rises to the south in the hills of Hawkstone, to the south-east at Market Drayton, to the east at Belton, to the north-east in the rising grounds extending towards Nantwich, and to the north-west in the undulating country near Whitchurch. (See Plate 29. fig. 2. and this wood-cut.) NLN.W. 5.S.E. 3. * Superficial Gravel, &c. a. Marlstone. b. Lower Lias. c. Saliferous Red Marl. d. Red Sandstone. The western boundary is ill defined, owing to the low and featureless form of the ground and its being covered by vast accumulations of gravel, sand, and peat-bog. It is, therefore, possible that the Lias may extend in this direction to some distance ; but, even assuming that it does not, and limiting the boundary by a line passing from Wem and Edstaston to Burley Dam, east of Combermere, places where the formation has LIAS IN SHROPSHIRE AND CHESHIRE. 23 been detected, we find that this bowl has a length of about ten, and a breadth of three to four and a half miles’, The greater part of this district consists of Lower Lias Shale, but the overlying subdivision of the Marlstone is also apparent. Marlstone —This member of the Lias is well exposed in the hill on which the church of Prees is built, (see centre of wood-cut above, and Plate 29. fig. 2.) both in quarries and by the sides of the roads, dipping to the north-north-east at low angles. The upper beds are composed of yellowish and. greenish thin-bedded sandstone, slightly micaceous, and in part calcareous; the middle, of other yellowish sandstones, some of which are more calcareous ; and the lowest beds, of sandy, dark-coloured slaty marl, and shale with flattened spheroids of impure blue Lias limestone, which are undistinguishable from the well-known cement-stones of the Yorkshire coast. The fossils which I obtained are those which best characterize the Marlstone in Worcestershire and Gloucestershire, viz. Avicula inequivalvis. M. C. t. 244. f. 2. Pecten equivalvis. M. C. t. 136. f. 1. Gryphea gigantea. M. C. t. 391. together with an Ammonite which appears to be referrible to Ammonites geometricus (Phillips) of the Yorkshire Lias. Lower Lias.—The Lower Lias consists entirely of finely laminated shale, as proved by shafts which have been sunk on Wolliston Common. In the vicinity of Burley Dam, some of the beds are so hard as to have induced Lord Combermere to quarry them for slating purposes, and others at the same locality being slightly bituminous have very much the mineral aspect of Kimmeridge Coal*. At Lightwood Green, the shale was found to contain nodules of ferruginous cement-stone : while at Cloverly, beneath nu- merous beds of dark marly shale, occurred one thin band of hard white stone with others of a blue colour. These bands have been traced by the Rev. Thomas Egerton, from Moreton Wood near Cloverly Hall, to Audlem and Burley Dam. The natural facilities for examining the deposit are few, the surface being generally covered by superficial clay and coarse gravel, sometimes to the thickness of twenty or thirty yards, but its characters have been abundantly ascertained by borings for coal at Heathgate, Moreton Wood, Prees Wood, Calver Hall, Burley Dam, Marchamly, Cloverly, » At Moreton Wood the Lias dips westerly, thus indicating, that it is there near the eastern side of the basin ; whilst at Audlem and Burley Dam, along the north-eastern and northern boundary, the strata dip south-west and south, at angles varying from 5° to 7°. Iam much indebted to the Rev. T. Egerton and the Rev. W. Egerton for their assistance in determining the outlines of this mass of Lias. 2 The Shale which forms the base of the upper division of the Oolitic series, occurs extensively in the coast cliffs at Kimmeridge, in the Isle of Purbeck, and hence it has been termed Kimmeridge clay. Some of the beds are very bituminous, and being occasionally used as fuel, are called Kimmeridge coal. The mineralogical cha- racters of this formation so closely resemble coal shale, that those unacquainted with its stratigraphical position and zoological contents, particularly in Oxfordshire and other interior parts of the kingdom, have frequently sunk into it in search of coal!! See Outlines of the Geology of England and Wales, p. 177. c 2 24 LIAS IN SHROPSHIRE AND CHESHIRE. and Wolliston Commons, &c. It is partially exposed between the escarpment of marl- stone at Prees, and the talus of Red Marl and New Red Sandstone of the Hawkstone Hills : there are also several outcrops of the strata between Marchamly on the south, and the rising grounds of Audlem and Burley Dam on the north. The relations of the Lower Lias to the New Red Sandstone are best seen near the eastern extremity of the Hawkstone ridge ; and the water forming the series of ponds to the north of Hawk- stone, is probably borne up by the marls of the New Red System. } Cloverly Hall, the seat of Mr. Dod, may be taken as a centre around which the lias shale is of the greatest thickness. On Wolliston Common, for example, in one of the attempts to find coal, after sinking two hundred and forty feet, the strata were bored to the further depth of one hundred and fifty, making a total of about four hundred feet. A little black lignite or jet was found in one instance, but nothing to justify the most remote probability of the formation containing coal. At the mouth of one of the trial pits I collected many fossils, and with the assistance of Mr. Dod and the Rev. T. Egerton, the following list has been completed : Ammonites Bucklandi. M. C. t. 130. Gryphea incurva. (See wood-cut, p. 19. f. 2.) ————- communis... M. C. t. 107. Maccullochii. M. C. pl. 547. f.1. ae Conybeart. M.C.t. 131. Modiola minima. M. C. t. 210. f. 5—7. — — planicosta. M.C.t. 406.1. 5 & 7. Pecten. An unpublished species, occurring also —— planorbis. M.C. t. 448. in the Brora Lower Shale; see memoir SS" resembling planicosta (small). — a New species (large and spinose). ee ee A beautiful small species re- sembling one published in Zieten’s Ammo- nites of the Wirtemberg Lias, &c. Mi3C: 4.137. tS: Small variety. Astarte elegans. Voltz sur les Bélem- nites, pl. 1. fig. 11. p. 38. Belemnites suhbclavatus. — portions of another species, Cidaris. ‘This is the first example I have met with in the Lias of any part of the body of Echinodermata, although many spines be- longing to this family have been found in the Lias of Gloucestershire, and at Lyme Regis. Geol. Trans., vol. 2. p. 320. Pentacrinites scalaris (Goldfuss). Plagiostoma giganteum. M. C.t. 77. M. C. t. 114. f. 4; Pullastra. Unpublished; also found at Brora. Geol. Trans., vol. 2. p. 320. Rostellaria. Spirifer Walcotti? M. C. t. 377. f. 2. Tellina Unpublished, probably 2 species (see memoir on Brora ut supra). Turritella. Small unpublished species, pro- bably same as at Banz, Germany. Unio Listeri? M.C. t. 154. f. 1, 3, & 4. Small portions of fishes or Crustacea ? — pectinoides. This list of fossils satisfactorily establishes the precise age of the beds, for besides containing the Ammonites Bucklandi, Conybeari, and planicosta, characteristic of the Lower Lias, we have the Ammonites Planorbis and Modiola mimma, both of. which are distinguishing fossils of the same beds in Gloucestershire and Worcestershire. It was gratifying to find in this detached basin of North Salop, shells identical with certain LIAS IN SHROPSHIRE AND CHESHIRE. 25 unpublished species first brought to notice by my visit to Brora, Sutherlandshire, the strata of which distant tract, containing a sort of coal, were by means of their organic remains identified with similar carbonaceous strata of the Oolitic system in the eastern moorlands of Yorkshire. Had the Lias of this Salopian tract contained coal as good as that found in the Oolitic formations of Whitby and of Brora, it might have been ques- tionable whether in a country so distant from any deposit of the old or true coal, it would not have been worth extracting; but no trials have brought to light any portion of combustible matter, whether termed lignite or impure coal, worthy of the name of a bed!. To convince the resident gentry and speculators of Northern Salop who are not aware of the value of the evidence afforded by organic remains, of the hopelessness of their search after coal, I beg to repeat, that the black shale is wnderlaid by the saliferous marls of the New Red Sandstone. In addition to the instances already given I may state, that the sinkings of Sir Corbet Corbet, at Adderley, opposite Kent’s Rough, and near the northern edge of the basin, proved this fact; for upon piercing the black shale to the depth of 300 feet a brine spring was reached! A similar infraposition of saliferous marls may be seen at Moss Hill farm, near Audlem. Lastly, an examination of the annexed wood-cut, and the map will show, that the basin not only rests upon mar!s and other strata of the New Red System, but is surrounded by them, and a reference to the general tabular view attached to this work will prove that the whole of the enormously thick system of the New Red Sandstone (as fully expanded here as in any part of En- gland,) lies between the black shale and the true coal measures. If coal really passes be- neath any portion of this country, it ought to be first sought for at points nearer to Oswestry, Chirk, Wrexham, Shrewsbury, Wellington, Newport, and Madeley in Staffordshire, in short, towards the outcrop of the coal measures which rise nearly on all sides from beneath the New Red Sandstone. Now as this tract of Cloverly and Prees, lies in the centre of the circle mentioned, it is necessarily the very spot in the whole area where the search for coal is the most hopeless, being that where the overlying deposits are thickest. (See Plate 29. fig. 23.) W.S.W. ENE. 4 Oswestry. Prees. North of Staffordshire. a. Marlstone. b. Lower Lias. c. Saliferous Marl, &c. d. New Red Sandstone. e. Calcareous Conglomerate and Lower New Red Sandstone. f. Coal Measures. 1 The working of the Brora Coal, though undertaken with the greatest spirit and continued at considerable expense by the late Duke of Sutherland, has now been entirely abandoned, owing to its pyritous impure quality and consequent tendency to spontaneous combustion. (See Geol. Trans., vol. 11. p. 293.) 26 LIAS IN SHROPSHIRE AND CHESHIRE. But if no useful practical results attend the discovery of this large mass of Lias, its detached position gives rise to interesting geological speculations. Seeing that it is sixty miles from the nearest point of the main escarpment of that formation in Worcestershire and Warwickshire, and nearly two hundred miles distant from the Lias of the north-east coast of Ireland, may we infer that the deposit was at one time continuous between these remote places? Was it connected at any period with those still more remote beds of the same age, and containing the same fossils, which are spread over the Hebrides, and appear at Brora on the north-east coast of Scotland? Or, shall we conclude that these isolated patches were originally deposited in widely distant bays, separated from each other by ridges of older rock ? It is perhaps impossible to answer satisfactorily all these questions, but in a future chapter I shall endeavour to show, that in this region at all events, certain phenomena of elevation entitle us to speculate on the probable former connexion of the outher of North Salop, with the main mass of the formation in Warwickshire and Wor- cestershire. CHAPTER III. NEW RED SYSTEM. UPPER FORMATIONS. 1. Saliferous Marls, §c.—2. Red Sandstone and Quartzose Conglomerate. IN the preceding chapter it has been shown, that the Lias is succeeded by beds of green and red marl, constituting the upper portion of the great series of strata, called in the annexed stratigraphical table the New Red System. In this'system are included all those deposits of marl, sandstone, and limestone, which lie between the Lias and the car- boniferous rocks, and which from their great development in certain parts of the island, are capable of being divided into formations, by differences in lithological and fossili- ferous characters. In the South-west of England, Messrs. Buckland and Conybeare’ have described them as consisting of upper marls, central sandstones, and a lower deposit of conglomerate, composed of fragments of carboniferous limestone cemented by a calcareous paste containing magnesia. ‘The last-mentioned rock, called by them the Dolomitic conglomerate, is the equivalent of the magnesian limestone of Durham and Yorkshire, and lies unconformably upon the coal measures. In the North-east of En- ' With regret I observe, that in reference to this system, my distinguished friends Messrs. Buckland and Conybeare have recently abandoned (it is to be hoped for a short time only) the simple English name of New Red Sandstone, adopting the Greek derivative “ Pcecilitic”” or “‘ Poikilitic,” which being translated means variegated or spotted, the “‘ Bunter” of the Germans, or “Irisé” of the French. There are strong reasons why this hard word should not be received in our geological tables. 1st. There are great masses of the New Red Sand- stone which are not spotted or variegated. Q2ndly. There are vast tracts of England, Scotland, and Ireland, in which the Old Red Sandstone is quite as much spotted as the New. Now, as the great object of nomenclature and classification is to simplify, I cannot perceive why in the very region, of all others in Europe, where the di- stinctions which have led to a great stratigraphical separation between the New and Old Red Sandstones are best displayed, a name should now be borrowed from the French, which with equal fitness may be applied to either of these systems, since it expresses nothing more than a lithological feature common to them both. I therefore earnestly hope that the long-established and well-understood names of New and Old Red Sand- stone, the one above, the other below the coal measures, may be adhered to by all British geologists. In France the nomenclature of Brongniart might well be received, since in that country there is no great system representing the Old Red Sandstone of the British Islands, though we know that it is largely developed in Norway, and, according to Mr, Lyell, in Silesia and Bohemia. (See Principles of Geology, vol, iv. p. 313. Ed. 4.) 28 NEW RED SYSTEM. gland, however, where the lower members of this system are much more fully developed, the subsequent researches of Professor Sedgwick have thrown a new light on these re- lations, proving that a great thickness of sandstone is there interpolated between the magnesian limestone and the carboniferous strata; and further establishing the important fact, that the coal measures of that region sometimes pass conformably into the lower New Red Sandstone’. I now proceed to show, that in the central counties, where its structure was once deemed “‘ obscure to the most acute geologists?,” this system may also be subdivided into formations, representing those of the North of England ; an ac- quaintance with which, will be found of great practical importance, in the neighbour- hood of the underlying coal fields. In the descending order these formations are— 1. Saliferous Marls, &c. 2. Red Sandstone and quartzose Conglomerate. 3. Calcareous Conglomerate = Magnesian Limestone. 4. Lower Red Sandstone. a. Lower Lias. b. Saliferous Marls, &c. c. Red Sandstone and Quartzose Conglomerate. d. Calcareous Conglomerate. e. Lower New Red Sandstone. f. Upper Coal Measures. Before describing these deposits, it is desirable to cast a glance over the map, and consider their geographical position as a whole. To the south-west of Gloucester they occupy a mere band, which after many contractions and expansions between Newent, the Malvern Hills and the Severn, finally spreads out in the plains of Worcestershire. Thence the Lias and Oolite rapidly receding in a north-easterly direction, the area of the New Red Sandstone is greatly enlarged; and finally where the Silurian and Cambrian rocks terminate abruptly near Shrewsbury, the Red Sandstone wrapping round their edges, is extended over a large region, the greatest width of which, from the coal-field of Chirk and Oswestry on the west, to the Lias of Leicestershire on the east, is not less than seventy-five miles. The following observations apply to the western portion of this area, and to some of those central districts where the coal-measures and older rocks protrude through the younger deposits. 1 Professor Sedgwick, Geol. Trans., vol. iii., thus identified this Lower New Red Sandstone with the “‘Rodte- todte-liegende” of German geologists; see account of this rock, in the next Chapter. 2 Buckland and Conybeare, Geol. Trans., vol. i. p. 299. New Series. The passage alluded to, is,—‘* The Newer Red Sandstone exhibitmg throughout its whole course an identity of character and composition, is ab- solutely continuous from the points in this district (Bristol and Tortworth) where it rests unconformably on the coal measures, to the plains of Salop, where its relations to the coal measures have appeared obscure to the most acute geologists.” (1825.) SALIFEROUS MARLS AND SANDSTONE. 29 1. Sahferous Marls and Sandstone. Foreign Synonyms.—‘ Keuper” of the Germans, ‘‘ Marnes irisées”’ of the French. (h. of coloured section, Plate 29. fig. 1. See also A of woodcut 1. p. 14. cc. of woodcuts 3 and 4. pp. 22 and 26, and 6. of woodcut 5. p. 28.) The whole of the New Red System, as seen in the narrow tract near Newnham and Flaxley, in Gloucestershire, is exhibited only in the form of red and green marls, which, on the east, pass upwards into Lias, and on the west repose unconformably upon the Olid Red Sandstone and Silurian Rocks. At Tibberton, five miles west of Gloucester, they include courses of hardish sandy marlstone, of a light green colour, the upper- most of which is nearly as white as chalk, and sometimes of a slightly brecciated structure. No hard stone occurs in this formation between Gloucester and Newent. As, however, we proceed northwards, the Burg Hill quarries, situated near the village of Stainton, afford an exception, and contain a sandy marlstone of lightish green and flesh colours, in some beds almost a grass-green, passing into calcareous, slightly micaceous grit. From the neighbourhood of Gloucester to the north of Upton, the Severn flows through soft Red Marl, exhibiting on its banks (as at the Mythe, north of Tewkesbury, and near Upton) vertical sections of red and green beds, with spots of each colour. Here the marls are of great thickness, and extend westward, almost to the foot of the Malvern Hills, from which theyare separated by only thin zones of sandstone and occasional conglomerates. The junction line of the upper beds with the Lias, ranging from Glou- cester to the north-east of Worcester, has been already described. The western boundary of the formation in Worcestershire cannot be very accurately defined, in consequence of the gravel which obscures so much of this low country; but, in general terms, it may be stated that the marls reach within a short distance of the Malvern and Abberley Hills. Subordinate to these marls, and not far removed from their junction with the Lias, are beds of whitish sandstone, which form thin courses at Combe Hill, west of Cheltenham ; and at Bushley, west of Tewkesbury. At Longden they are thicker, and at Ripple on the left bank of the Severn four miles north of Tewkesbury, they swell out to twenty and thirty feet. This rock doubtless represents one of the sandstones subordinate to red and green marls which occur at Coburg, Stuttgard, and other parts of Germany, and at Luneville in France; constituting the ‘‘Keuper” formation of foreign geologists’. 1 To convey to my readers some notion of the nature and succession of the strata comprehended by the Germans under the term “ Keuper,” I herewith annex a section of that formation at Stuttgard, made by Pro- fessor Sedgwick and myself in 1828. From this and subsequent observations of my own, particularly in the neighbourhood of Niirnberg, Coburg, and Gottingen (1829), I came to the conclusion that the German forma- tion, as established by Humboldt and Hoffmann, for the purpose of distinguishing the red marls and sandstone which rest upon the Muschelkalk, from those which occur beneath that limestone was the true equivalent of the upper division of our English New Red Sandstone. I afterwards stated this opinion to the Geological Society, D 30 SALIFEROUS MARLS AND SANDSTONE. Throughout its range in Gloucestershire and Worcestershire, the red marl is never inclined at a greater angle than 15°, the average dip of the strata rarely exceeding 5° to 8°, and always to the east, or a little north or south of that point. The salt springs at Droitwich, and the numerous saline waters which rise to the surface upon the edges of the Lias, extending thence to Gloucester, have all their source in the same formation. These brine springs and the surrounding strata, were first described by pointing out at the same time the rocks in Germany and France which I conceived to be the equivalents of the other British secondary formations. (See Geol. Proc., vol. i. p. 358, with references to the works of Alberti, Hoffmann, Jager, &c.) Section of the Keuper descending from the village of Degerloch to Stutigard. feet. [ 1. Rusty brown and bluish marls with sandy stone bands, shells appearing in the lower part . 10 to 12 i 2. Lias limestone having a compact ferruginous exterior, and a blue interior, with many of the fossils of our Lias, and much resembling some beds in the Hebrides, as well as the lower claystones of Gloucestershire. Beds, nine inches thick, quarried for flagstones .... . 9 to 10 lias poe © . Marls and white gritty sandstone, passage into Keuper (similar to the passage described in HCA (O1d (Eek OLN Ta ee oes cies ieee cy MEN et eOGG © MRA SENG fo eek S 10 to 12 4, Purple and green argillaceous marl with some hard, flaglike, slaty, micaceous sandstone . . 60 to 80 5. White quartzose grits, used as millstones, with green spots of marl (Thon-gallen), weathering reddish, but white on fracture; containing large stems of plants, some of which preserve their carbonaceous coating. (These beds are apparently m the place of the Ripple sand- 8 Stone Cescriped laste stexta) eta mrt went as ce ease: Walenuny a eon Mcnt: maou: Stee teens tuyere 16 to 20 S & <6. Keuper marl, like No. 4, but differing in containing subordinate thin beds of sandstone and ke a, millstone-grit, into which the marly layers pass horizontally .............. 80 to 100 7. Marls with bands of compact green marlstone (like that of Burghill, Luneville and Coburg), passing into compactish limestone, with veins of sulphate of barytes and carbonate of lime. 60 to 70 8. Thinly laminated, shivery marls, 20 to 30 and 40 bands exposed in one section (thickness unknown). The Muschelkalk limestone, which is wanting in the English New Red System, lies below the above-mentioned strata, and is seen on the banks of the river Neckar. The prevailing colours of the marls and sandstones at Stuttgard are purple and chocolate ; while at Coburg the principal masses are hard calcareous grits of lively green colours, and at Niirnberg, the edifices of which city are built of Keuper, the rock is a pale red sandstone. Among the plants of the Keuper figured by Dr. Jager and M. Adolphe Brongniart, are Kquisetum columnare, Brong., Calumites arenaceus, Brong., Calamites arenaceus minor, Jager, Lycopodiolithes phlegmaroides, Sternberg (Lycopodites of Brong.). See figures of other plants in this formation at Coburg in a work by Dr. Berger (Die Versteinerungen der Coburger Gegend, 1832). he shells consist of Posidonia Keuperi, Voltz, P. minuta Alberti, Savicava Blainvillii, and other casts of undescribed species. In the lower beds some of the Muschelkalk fossils appear, such as, Lima lineata, Avicula socialis, Schloth., Avicula subcostata, A. lineata, and Perna vetusta, Goldf. Fishes occur in the formation, and they have been distinctly separated by Agassiz from those of the Lias. He remarks that ‘this is the most recent deposit in which the fishes of the family of Ganoids have the vertebral column prolonged into an unequal lobe, reaching to the extremity of the caudal fin.” But the most remarkable remains are the Saurians, named by Dr. Jiger, Phytosaurus cylindricodon, and P. cubicodon. Some of the organic remains of this formation indicate a transition downwards from the base of the oolitic system, and one or two of the plants common to the Keuper and Lower Oolite are identical; for example, the Hquisetum colum- nare, Brongn. Oncylogonatum carbonarium, Kénig, Geol. Trans., vol. ii, p. 800, so abundant in the coal of the oolite at Brora, is equally common in the Keuper of Germany. In the grand duchy of Baden, where the same plant is abundantly found in schist of the Keuper formation, coal is also associated; a fact which rests on the authority of that excellent observer M. Voltz of Strasburg. (See other observations on the contents of the Keuper formation, and its separation from the Grés bigarré, p. 36, et seq.) SALIFEROUS MARLS. 31 Mr. Leonard Horner!. Dr. Hastings has recently published an interesting account of the saliferous district around Worcester, from which we learn, that though the springs at Droitwich have been in use since the time of the Romans, it is only within these few years, that rock salt has been discovered in this neighbourhood, a fact which seems in- explicable when we recollect that many years have elapsed since it was shown by Dr. Holland’, that masses of rock salt were the source of all the brine springs in Cheshire, the marls of which county are precisely of the same age and composition as those of Worcestershire. The account of the Droitwich springs in Nash’s History of Worcester, might alone have afforded sufficient evidence of the existence of a subjacent body of rock salt, the trial sections detailed therein having passed through “rivers of salt” and al- ternating beds of clay, marl, and gypsum, to a “‘ rock of salt.” Notwithstanding these trials, it was only in the year 1828 that a Cheshire brine smeller, judging from various subsidences and chasms in the marl, fixed upon Stoke Prior, three miles east of Droit- wich, as a spot where productive mines might be sunk. The attempt verified the cor- rectness of his opinion and led to the discovery of rock salt. The relations of these beds of salt are well explained in the following section of the works at Stoke Prior (taken from the pamphlet of Dr. Hastings), which affords a good insight into the general struc- ture of the red mar! of this district, and shows the same association of salt with sulphate of lime, as in other parts of Europe. ft. in. a= Wed-andloreentmarl! . aye ees ee ay 2 es dee ONL O uke cece Canter Tic eulite 0 b. Red and green marl with few distinct appearances o bedding, traversed by veins of gypsum usually vertical. ......... Rok Ot © ih ig o MaprO oan wen Secop hy cee 195 0 ce. Redmarl, containing “‘rock salt,” nearly pure, distributed like the gypsum inthe overlyingmass. 24 0 d. First layer of rock salt, red coloured and AKU PULErt eeeereee cee en erent « Se ee ee mee 6 ex Uvedsmanlawith- weln spor sal fn: Sway Ate rcua ro: care eh «eee ves ots aa "es ei-» SS Pls Oe | aeons 3.6 f. 2nd rock salt, containing 25 per cent. of reddish marl. ...... Re at ee re ere 10 O g- Green marlayer See oo). eA ee Fat ae ett Se ee 5 are a’ oa a 1 6 h. Red marl with veins of salt .......... med ee Gee 4S pe pe oe eee tae 12 6 PE MOUOSTOCK. Sal GSE Me eee PEE Ey ace etc are ne WME ce we CRT yt RS yoy gigs cg ah eect cate: 6 6 j- Red marl layer with veins of salt... ......-.0000000 ees EM Wa ea Gs a rsits 2 6 k. 4th, or thick bed of rock salt, including from 7 to 20 feet of marl........-+-2+8: 39 0 t, Red mar! with veins of salt of flesh colour ..........++e.ee02+e0ceee. ei LES w m. Sth rock salt; 30 feet thick and no bottom. ........2.ss.:ceee00-% Se LM rahe 30 0 feet 460 0 ' Geol. Trans., Old Series, vol. ii. p. 94. 2 Geol. Trans., Old Series, vol. i. p. 38. p 2 OZ SALIFEROUS MARLS. These sinkings through a portion of the saliferous marls at Stoke Prior in Worcester- shire! afford us some means of judging of the maximum thickness of this upper member of the New Red System, which we shall not exaggerate if we compute it at upwards of six hundred feet. By reference to the map it will be seen that these salt mines at Stoke Prior are little more than two miles distant from the edge of the Lias at Forest Hill, near Hanbury ; and as the whole body of these marls is overlaid by that formation, the section at this spot is one of the most convincing proofs in England of the exact position of the member of the New Red System, which in England is the matrix of rock salt. The perfectly analo- gous position of the Cheshire salt, has recently been determined by the discovery of the basin of Lias near Whitchurch and Nantwich. (See Plate 29. figs. 2 and 3, and wood- cut 4. p. 25.) Numberless sections in Worcestershire, Staffordshire, or Shropshire, prove that neither rock salt nor salt springs occur in the middle or lower members of the New Red Sandstone ; and hence the term “‘ Saliferous”’ as applied to the whole system appears objectionable, since the marls in which the salt lies, constitute only the upper portion of the mass we are now considering under the general head of ‘‘ the New Red System.” For though in certain parts of Germany, salt appears to pervade the underlying “‘ Bunter Sandstein,” as we learn from the excellent monograph of Alberti*, we also know that in other tracts of central Europe it abounds in tertiary strata (Wielitzka in Poland). At Cardona, in Spain, it is found in rocks of the age of our green sand ; in the Austrian Alps it has been shown by Professor Sedgwick and myself to occur in limestone of the oolitic system’; whilst in many countries, including England, saline springs occasionally burst out from the carboniferous and older systems of rock. I have never detected any traces of organic remains in this upper formation of the New Red System in England, though in Germany I have observed them in several lo- calities, in the alternating masses of marl and sandstone which there constitute the Keuper. (See note, p. 30.) In amemoir communicated to the Geological Society while these pages are going through the press, Dr. Buckland has described the sandstone of Warwick, Pyle in Glamorganshire, Sutton Mallet near Bridgewater, and several localities near Taunton, asa part of the Keuper formation ; resting his conclusions on the lithological character of the stone, and the discovery of an unknown species of Saurian, 1 Owing to the undulating nature of the country, the natural sections of red and green marl near Droitwich are clearly exposed; but at Stoke Prior the surface is level, and has been extensively denuded and covered by gravel; it is therefore by shaft sections only that we there ascertam the succession of the strata. I recently visited this spot to examine the sides of a new shaft, and from the appearance of the spotted marls and gypseous beds which were exposed, J have no doubt that the section given in the woodcut, p. 31, may be depended upon. 2 Monographie des bunten Sandsteins, Muschelkalks und Keuper. Stuttgard, 1834. This work is full of merit and accurate research, though I cannot say that the new word Trzas of the author, appears to me a happy selection in reference to these three formations; nor can we apply it in England, seeing that one of them, the Muschelkalk, is wanting. 3 Geol. Trans., vol. iii. p. 30; Proceedings Geol. Soc., vol. i. p. 227; and Phil. Mag., vol. viii. pp. 64 and 81. plate 2. SALIFEROUS MARLS. 33 found some years ago in the sandstone of Warwick, and considered by Dr. Buckland to be allied to the genus Phytosaurus, associated with fragments of plants, which are in too mutilated a state to allow the species to be ascertained. This view does not coincide with my conclusions respecting the English equivalents of the Keuper ; for I believe that the German formation is represented by our saliferous marls, with the sandstone before described ; and it will presently be shown that masses of rock much resembling that of Warwick, and apparently occupying the same stra- tigraphical position, must be considered to form an integral part of the underlying New Red Sandstone (Bunter Sandstein, Grés bigarré). ‘The occurrence of a Saurian, even if the genus were established, could not prove the beds of Warwick to belong to the Keuper; for we know that in the upper secondary formations, the remains of Hylco- saurus have been discovered both in the Lower Green Sand and in the Wealden, though the first of these formations is of marine, and the second of freshwater or estuary origin; while with reference to the rocks now under consideration, M. Voltz has taught us, that Saurians occur in the Grés bigarré or Red Sandstone beneath the Muschelkalk, as well as in the Keuper above it. The fossils of the overlying and underlying formations in England being of marine origin, there is little doubt that the red marl must also have been deposited beneath the sea. In Germany and in France this inference is established by the presence of marine remains in the Keuper, Muschelkalk, and Bunter Sandstein, the three upper formations of the system ; the first of which, as before mentioned, represents our saliferous marls. The second or great calcareous formation has not yet been discovered in the British Isles ; and the third is the equivalent of those massive central sandstones of our system treated of in the following part of this chapter. The numerous brine springs as well as masses of rock salt which are contained in the red marl, seem to offer additional proofs of the marine origin of these deposits, since Dr. Daubeny has shown, that in many of these saline sources there is an admixture of iodine, a principle which is confined to the sea and its productions. This argument is not however to be considered decisive, but only as forming a portion of cumulative evidence, which taken in conjunction with that of the remains occurring in the deposits of this age on the Continent, fortifies the con- clusion that our saliferous marls are of marine origin; for it might be said that iodine and chloride of sodium have been derived in the first instance from the interior of the earth, and that the ocean may have owed its saltness to beds of rock salt, as well as that rock salt owes its origin to the evaporation of sea-water. These considerations lead us naturally to an examination of the origin of the mineral springs so abundant in the Vales of Gloucester, Worcester, &c. 34 MINERAL SPRINGS OF GLOUCESTERSHIRE AND WORCESTERSHIRE. Mineral Springs of Gloucestershire and Worcestershire. The true nature and geological position of the strata through which these springs rise had not been described before the year 1833, when I made them known in a brief sketch of the geology of the environs of Cheltenham. In one of the previously pub- lished analyses, the Cotteswold Hills were assumed to be ‘‘ magnesian limestone,” and the blue clay through which the waters ascend, was said to cover the limestone. That this clay, the lower Lias, passes beneath the calcareous rocks, is a fact now known to every geologist (See woodcut 1. p. 14. and Pl. 29. fig. 1.); and instead of the magnesian limestone, which does not exist in this district, the stone of the adjoining hills is proved to be the Inferior Oolite. Again, in a recent work, the production of an able chemist, the waters are supposed to rise through sand’. It was therefore desirable to show distinctly, that the lowest marly and argillaceous beds of the Lias formation, are really the strata through which these waters find their way to the surface. For a long time after their first discovery at Cheltenham, it was the general belief that they had only one source; but numerous sinkings, at depths from eighty to one hundred and thirty feet, adjacent to, and at considerable distances from the old springs, have established the fact, that many strata were saturated with water, holding in solution the chloride of sodium, the sulphates of soda and magnesia, and other mineral substances. From the analyses of these waters by several chemists, it appears that their principal constituents are the chloride of sodium or sea salt, and the sulphates of soda and mag- nesia ; sulphate of lime, oxide of iron, and chloride of magnesium, being present in some wells only, and in much smaller quantities*. The analyses have also proved, that these substances vary much in their relative proportions at different sources, a circum- stance which must arise from the waters changing their composition with the varied mineral structure of the strata which they traverse. Besides the ingredients just men- tioned, iodine and bromine have, as already stated, been detected in several of the sources by Dr. Daubeny’, who has endeavoured to ascertain whether these two active principles, which the French chemists had recently discovered in modern marine pro- ductions, did not also exist in mineral salt waters, issuing from strata which geologists consider to have been formed beneath the sea; and his examination has established the 1 Thermal and Mineral Springs, by Dr. Gairdner, 1832, p. 419: an excellent work. The mistake in this case is that of confounding the superficial sandy detritus of the district, with the formation on which it rests. 2 The waters were formerly analysed by Brande and Parkes, subsequently by Dr. Scudamore and Dr. Daubeny. Professor Daniell has examined those of Pittville, and Mr. Cooper has recently made a very elaborate analysis of those of Montpelier, with the details of which I am not acquainted. His observations, I believe, coincide with those of Dr. Daubeny, in the detection of iodine and bromine. 3 Philosophical Transactions, May, 18380. MINERAL SPRINGS OF GLOUCESTERSHIRE AND WORCESTERSHIRE. 35 existence of iodine and bromine, not only in the waters of Cheltenham, but also in the greater number of the salt-springs of Great Britain. The previous observations in this chapter have shown, that the great subterranean storehouse of the rock salt and brine springs of England, is the red marl or upper member of the New Red Sandstone’, which is immediately subjacent to the Lias. (See Map. Pl. 29. fig. 1.) Accordingly we find that sea salt is present in still larger quantities in those wells which occur near the western edge of the formation, where the Lias forms only a thin covering above the red marls. At the new spa near Tewkesbury, the water, though very slightly saline near the surface, was found to be much more impregnated with salt as the sinking was carried downwards; and I have no doubt that similar results would follow, by deepening any of the mineral sources which are so numerous in the Vale of Gloucester, those of Walton, the bottom of Church Down Hill, &c., for instance. Even at Chel- tenham, when experimental borings were made to the depth of two hundred and sixty feet below the surface, the water of the lowest stratum of marl or clay was found to be much more highly charged with the common sea salt, and to contain less of the sul- phates, than the existing wells, none of which have been sunk to a greater depth than one hundred and thirty feet. These facts can be only accounted for under the supposition, that the source of the saline ingredients of those waters is the Saliferous Red Marl or Keuper, the uppermost strata of which must, from their known inclination, lie at depths of several hundred feet below the town of Cheltenham. (See Pl. 29. fig. 1.) If this be the case, and salt water is continually flowing upon the inclined surfaces of these beds, we can readily explain why it occasionally rises to the surface; for being collected in the New Red System at higher levels than the surface of the Vale of Gloucester, it would naturally ascend to the original level by any cracks or openings which might present themselves in the overlying Lias’. The salt water having thus to rise through various strata of lias shale, loaded with sulphuret of iron, it is to be presumed, that during this passage certain chemical changes take place, which give to the waters their most valuable medicinal qualities. The most important process in this moist subterranean laboratory, is probably the decomposition of the sulphuret of iron, which supplies a large quantity of sulphate of the oxide of iron, an elaboration which must be highly accelerated by the structure of the incoherent and finely laminated beds, through which the pyrites is so widely disseminated. The sul- phuric acid, thus generated, will necessarily react on the different bases, such as mag- nesia and lime, which it may meet with in the strata, and form those sulphates so pre- ' See the memoir of Dr. Holland, Geol. Trans., vol. i. p- 38, and that of Mr. L: Horner, vol. vi. p. 95, Old Series; also the recent work of Dr. Hastings of Worcester. (See p. 32.) * The borings for mineral water at Cheltenham are, truly speaking, Artesian wells, and ought at once to explain to the inhabitants of the Vale of Gloucester, that no pure water can be obtained by sinking through the Lias in the vicinity of the mineral springs. 36 NEW. RED SANDSTONE, ETC. valent in the higher or pyritous beds of the Lias, the oxide of iron being at the same time more or less completely separated. By such means, it is presumed, these mineral waters, which are simply brine springs at great depth, acquire additional and valuable properties in their ascent. In suggesting this explanation, we must not, however, overlook the fact, that fresh water is perpetually falling from the atmosphere upon the surface of the Lias clay, and, more or less, percolating its uppermost strata. Many of the saline springs must therefore be affected by this cause, and the existing condition of the various wells in the Vale of Gloucester, may ultimately depend upon three causes :— 1. The supply of salt water from the marls of the New Red System, in the manner above described ; 2. The chemical action produced during the filtration of the salt water as it rises through the various strata of the Lias ; 3. The supply of fresh water from the atmosphere. The chemical relations, and medicinal virtues of these waters, have been well described in other treatises, and they are only mentioned in this place to convey a clear notion of their origin, and their dependence upon the geological structure of the district. This reasoning respecting the origin of the Gloucestershire mineral waters may be applied to all the mineral springs which rise through the Lias of the Vales of Worcester and Warwick. 2. Sandstone and Quartzose Conglomerates. Foreign Synonyms.—‘‘ Bunter Sandstein” (Ger.), ‘‘ Grés bigarré” (Fr.) The great arenaceous formation of red and variegated sandstones, constituting the Bunter Sandstein or Grés bigarré of continental geologists, is very largely developed in England, particularly in the counties of Salop, Stafford, and Worcester. In Germany, Poland, and the eastern parts of France, this formation is distinctly separated from the Keuper (our saliferous marls and sandstone), by the “ Muschelkalk”’ or shelly limestone. (See note, p. 30.) In England we have not yet succeeded in recognising the equi- valent of this limestone, and hence we have always wanted a clear line of separation between the formation described in the last chapter, and that which we are now to con- sider. When, however, we look to the vast development of the saliferous marls of our island the maximum thickness of which, including subordinate courses of sandstone, amounts to six or seven hundred feet, we should naturally be disposed to think that these comprise the whole. German formation called the ‘‘ Keuper,” and that the true equivalent of the Muschelkalk would be found rising from beneath these red and green marls, and surmounting the sandstones and conglomerates which constitute the central or chief masses of our New Red Sandstone. Now although I cannot yet completely obviate the difficulty arising from the absence of the Muschelkalk, I may observe that NEW RED SANDSTONE IN SHROPSHIRE. 3/ there exists a subcalcareous course in Shropshire, which appears to occupy the place of that formation. This course is exposed on the northern slopes of the Hawkstone and Clive Hills, particularly at Broughton, seven miles north of Shrewsbury, where its geological position is well defined ; for it has previously been shown, that there, the Saliferous Marls or Keuper passing beneath the Lias, rise up to the south-south-east, and overlie the massive sandstones of the Hawkstone Hills. The calcareous band at Broughton dips under the saliferous marls, and distinctly rests upon the solid sandstones of Clive, Grinshill, and Hawkstone ; and hence it seems to occupy precisely the position, which would be naturally assigned to the German Muschelkalk. (The position is ex- plained in this wood-cut.) SESE Soni F. Bilmarsh. Broughton. Clive. Grinshill. a. Saliferous Marls and Sandstone. ce New Red Sandstone = Bunter Sandstein. c*. White Sandstone of Grinshill included in the Red Sandstone. The beds at Broughton are so calcareous, that they have recently been tried for lime-burning, but they proved too earthy and sandy for that purpose. They are so thin bedded as almost to constitute a flagstone, a structure never discernible in the upper or central members of the New Red System, though it will hereafter appear, that this structure occurs in some beds of the Lower New Red Sandstone, and is common to many strata of the Old Red System. The upper beds at Broughton are red, marly, sandstone flags, passing down into hard, grey, fine-grained, calcareous grit, with rough uneven surfaces, breaking into flags three or four feet square, and used as wall-stones. On exposure, these flags weather to a dirty yellowish colour, and they then very much resemble certain sandy and rubbly beds of the Muschelkalk. At the depth of a few feet they are underlaid by beds of yellowish sandstone, containing hard, round, concre- tions of calcareous spar, and of sub-crystalline sandy limestone. In some instances, the lime is so much disseminated through the mass, as to give to the fresh fractured surface of the stone a ‘‘ chatoyant”’ lustre, and this appearance doubtless led to the construction of limekilns at this spot, for the rock in question is entitled to the name of bastard limestone. This rock also contains nests of calcareous spar, crystals of grey carbonate of copper, and sulphuret of iron, with occasionally small grains of black oxide of man- ganese diffused. Fully aware of the importance attached to the geological position of these calcareous courses, I have twice visited the Broughton quarries, in the hope of detecting some organic remains peculiar to the Muschelkalk, but without success. Still, however, I am of opinion, that, from their stratigraphical position, these calcareous beds of Broughton may prove to be the representatives of the Muschelkalk; and I trust that the day is not | E 38 NEW RED SANDSTONE IN SHROPSHIRE. distant, when further excavations along the northern slopes of the Clive and Hawkstone Hills, may lead to the discovery of the zoological evidences required’. Near Marchamley, the eastern end of the Hawkstone Hills, a natural section is seen in the following descending order, proceeding from north to south. 1. Beds of flaglike, deep red, sandy marlstone, the uppermost passing under red and green saliferous marls, with some lamine of greenish grey marl. bo . Thick-bedded dark red sandstone, weathering to a small cavernous or honeycomb surface, and resting on red and green marl. The strata 1. and 2. may perhaps be classed with the Keuper, or rather as the beds of passage from that formation to the great mass of New Red Sandstone. The calcareous course, however, is not so distinctly exhibited as at Broughton. 3. Hard, red sandstone, slightly calcareous and in parts cellular. On their extension to the west, these bands become of a yellowish grey colour, including veins of chalcedony, with nests of crystallized carbonate of lime, blue carbonate of copper, and black oxide of manganese dis- seminated both in particles and in small veins. 4, Thick masses of whitish soft sandstone without distinct lines of bedding. 5. Red sandstone appearing below the white sandstone. These beds form a part of the Hawkstone Ridge and terrace so justly admired, but other parts of the same escarpment present different characters, and the alternations above described, give way to large continuous masses of whitish yellow, thick-bedded, earthy sandstone, forming picturesque cliffs of rounded forms, from eighty to one hundred feet high. This sandstone is composed of semi-transparent grains of quartz, very minute, apparently rounded, with a small proportion of grey cement, chiefly argil- laceous, and it occasionally contains ‘‘ concretions about the size of a pea, of lamellar, white and flesh-coloured sulphate of barytes*.” It presents few clear lines of deposit, and is marked by many transverse fissures and seams of false bedding, features charac- teristic of all the sandy rocks of this system. The whole of the sandstone strata in the Hawkstone range, including the Clive and Harmour Hills, dip at a small angle to the north-north-west, partially surmounted, as before stated, by calcareous courses, which are supposed to represent the Muschelkalk, and passing beneath the saliferous marls which support the Lias. (P124. fig. 2.) In this country, therefore, having a clear line of demarcation for the top of the system, we know that the Hawkstone rocks constitute an integral portion of the great central mass of New Red Sandstone. The surface of the sandstone near the Hermitage, is occasionally of a bright green colour, which is sometimes due to green carbonate of copper, disseminated through the rock, as seen on the sides of the park ride leading to Marchamley, though some of the specimens owe 1 The most characteristic fossils of the Muschelkalk are Lima striata and L. lineata, Schlotheim ; Pecten levi- gatus and P. discites, Schloth.; Avicula socialis and A. Bronniit (Mytilus socialis, &c., of Schlotheim) ; with the well-known and beautiful Lily encrinite, Hncrinites liliiformis, and Ammonites nodosus. Some of the fos- sils of the Muschelkalk pass up into lower beds of the Keuper. (See note p. 30.) 2 Aikin, MSS. NEW RED SANDSTONE IN SHROPSHIRE. 39 their superficial green colour to the presence of a lichen. The existence of copper ore in rocks of the same age is well known in Cheshire, both in the Peckforton Hills and in Alderley Edge. Since I last visited Shropshire, copper ore has likewise been found, and works have been opened in the New Red Sandstone near Pradoe, on the property of the Hon. Thomas Kenyon. Specimens of the rock sent to me by Colonel Wingfield, indicate the dissemination of the green carbonate, in minute quantities through the mass of sandstone. At the Peckforton Hills I examined the trial shafts of the old mine in company with the proprietor, Sir Philip Egerton, Bart., and there the ore unques- tionably lies in veins and lumps, where the sandstone is dislocated and fissured. Further allusion, however, will be made to this subject and to the mineralized character of these sandstones, after the description of certain trap dykes which penetrate the New Red Sandstone of Shropshire. Mr. A. Aikin, with his usual mineralogical precision, had remarked, more than twenty years ago, that the rocks of Hawkstone were analogous to those of Alderley Edge, in containing traces of copper ore, ferruginous oxide of cobalt, together with concretions and veins of sulphate of barytes. These minerals were at that day held to be eminently characteristic of the Old Red Sandstone, having been cited by Werner as occurring abundantly in the older Red Sandstones of Germany; but we now know that these older German Sandstones (the rothe todte liegende), are not of greater antiquity than those which form the lower part of the New Red System. At Clive Hill, the highest part of the Broughton ridge before mentioned, and rising from beneath the calcareous courses supposed to represent the Muschelkalk, Mr. Arthur Aikin first observed ‘‘round concretions of fine sand, firmer than the surrounding matrix and much heavier, consisting of quartzy sand, cemented by sulphate of barytes, their size varying from the bulk of an apple to that of a pea. These concretions, being harder and less easily decomposable than the rest of the rock, project from its weathered surface and often become quite loose in the incoherent sand to which the rock is re- duced’.” Dark-coloured quartzose conglomerates rise from beneath these sandstones in the hills at Hodnet; and if we continue the section in direct descending order, from the escarpment at Hawkstone on the north, to the plains of Shrewsbury on the south, we pass through other and older strata of this group of the formation, composed of red sandstones, and much stiff red marl or clay. (See section, Pl. 29. fig. 3.) The Clive and Grinshill Hills are the south-western prolongations of the Hawk- stone sandstones. ‘The cliff at Grinshill exhibits the peculiar feature of a face of sixty- five to eighty feet, of a fine-grained, whitish sandstone, included between two masses of a red colour, the overlying stratum being a rubbly, thin-bedded red rock called ‘‘Fee;” the underlying mass, a deep-coloured red sandstone, which has been bored through in search of water to the depth of upwards of two hundred and twenty feet, without afford- ing any sensible difference in its composition. The red cap, or ‘‘ Fee,” is mere refuse or marly sandstone, and the red sandstone at the base of the hill is simply a soft thick- | 1 MSS. of Mr. Aikin. EQ 40 NEW RED SANDSTONE IN SHROPSHIRE. bedded red stone, undistinguishable from the rock in many other parts of its range. But the included mass of light-coloured free-stone is well worthy of description, being perhaps the finest example in England of so deep a section of stone of this quality, in the New Red System". Some of the beds are quite equal in value to any free-stone of the coal-measures, from which they differ in being entirely free from stains of carbo- naceous matter, and here and there slightly variegated by streaks of a delicate pink hue: others have also occasionally a yellow tinge due to the decomposition of iron pyrites. The stone is for the most part rather heavier than other free-stones, in consequence, as suggested by Mr. A. Aikin, of the grains of grey sand being contained in a cement composed chiefly of heavy spar (sulphate of barytes)*. The beds vary in thickness from two to eleven feet, and are generally so closely fitted to each other that there is only one very thin parting of clay from the top to the bottom of this fine face of rock’. The subjoined section affords the details. The strata dip about 6° north-north-west, by which inclination they pass distinctly beneath the calcareous bands of Broughton. Section of Grinshill Stone Quarries. Fee, pronounced “ Fay,’’ a red rubbly thin-bedded rock, with some marl......... 4 0 Flag-rock, yellowish and light brown colour, in thin beds, the thickest being fourteen inches; used for flagging, chimney-pieces, monuments, and other interior work .... 19 O Sand bed mine amchesideep, called Sesh 7y-eepatare) to see) 2) eens) -Seeuerten cules clones ote OP*9 HardyBurrs(Compacterac) ire. eas cere eke) ee ae ee 26 Coarse Freestone, rather mottled, of yellow, and reddish colours ; used for bridge-building, finerwalls, cc. 2sest.building=stone wat. 2 uc. Sis seb aur ern a 9 6 Grey Freestone .....-+-..... So ee ets ee ed bien Beta Pe NG Good light yellow Freestone, much preferred from its colour, underlaid by a thin seam of clay, the only wayboard in the quarry ..-.. 1... eset eee ee ee eee eee 11 O Good withthe mrcestonenert: mt mmr kets) ten chee etre Meer Bee ts ets cece rates tre meer fad ccs tote eae 2 10 Strong white Freestone; white with minute yellow grains ........+.+.+.--. Pe aihatd 8 O Sandy and bad Freestone ...... SEE irae sth ee eee ener pete ee BD) Bad Stone; sometimes used for walls, bridges, &c.. . ..- 2+ s+ het eer oe. Ge 9 O Soft yellow Sandstone, grains of sand cemented by a small quantity of decomposed felspar. 4 6 Sandstone of deep red colour in massive beds sunk through in search of water....... 222 0 Totalreet car sue. - ole 7 ee Len LL Ln ain, ici (lca Ce 1 Quarries of light-coloured sandstone sometimes of a delicate yellow colour, at others inclining to an olive tinge, and like the rock at Grinshill subordinate to the New Red Sandstone, occur at Runcorn, Cheshire, and at Warwick. 2 Aikin, MSS., note. s All the modern edifices in and around Shrewsbury are built of this durable light-coloured sandstone, the finest beds of which are so susceptible of being worked for the highest ornamental purposes, that the column and statue of General Lord Hill are both formed of them. The pillars in the colonnade of Onslow House, the residence of Colonel Wingfield, offer a beautiful example of the slightly tinged pink variety. NEW RED SANDSTONE IN SHROPSHIRE AND STAFFORDSHIRE. 4] Water is scarce along the edge of the escarpment, which has occasioned sinkings to be made at Grinshill in the red sandstone to the depth, as already stated, of 222 feet below the base of the quarry, when the borings were still in that rock. Mr. Aikin, however, well observes, ‘‘ a circumstance remarkably characteristic of this kind of sand- stone, is the great number of meres, or deep pools, which it contains. The outline of all these pools more or less approaches to circular; they receive no streams, and very often do not transmit any, the loss by percolation and evaporation being nearly sup- plied by the springs that occupy the middle and deepest part of their bottoms; I say nearly, because all that I have examined bear evident marks of gradual diminution: in many, this change has advanced so far as to convert the whole area, with the exception of a deep pit or two near the centre, into a peat moss, and some of the smaller and shallower ones are not only entirely filled up, but are even applied to the purposes of agri- culture.” (Geol. Trans. Old Series, vol. 1. p. 193.!) The Grinshill and Hawkstone range of sandstone is much denuded to the east and south-east, sinking gradually into the plain towards Newport, but it maintains an elevated outline to the west-south-west, and can also be followed, at intervals, to the east-north-east by Market Drayton into the high district of Ashley Heath, 803 feet above the sea. (See Map.) To the west-south-west it occupies Harmer Hill, Pim Hill, and the bold rocks at Ness Cliff, from one hundred to one hundred and fifty feet high. It is there, for the most part, a thick-bedded, deep red and yellowish, loosely cohering, quartzose sandstone, composed of minute rounded grains of quartz, of yellowish or brownish colour, with here and there a scale of mica, cemented together by a small portion of red clay. Veins of small dimensions, com- posed of quartz, cemented by a chalcedonic paste, not unfrequently traverse the beds, projecting on the surface of the friable sandstone. Further particulars respecting these veins and the derangement of the strata, will be pointed out in a subsequent chapter, after describing the trap dykes of Acton Reynolds. Beds of sandstone of this age are only to be seen at rare intervals in the great plain of Shrewsbury, the surface being loaded with immense accumulations of gravel, clay, sand and boulders. Such sandstones, however, occupy the northern and north-eastern portion of that plain, and are separated from the coal-fields by bands of dolomitic conglomerate and lower red sandstone. By pursuing a transverse section from the Lias of Prees, through the underlying red marls and sandstone of the Hawkstone and Grinshill Hills, and thence to the edges of the Shrewsbury coal-field, (see Pl. 29, fig. 3.) we best see the great expansion of the New Red System in Shropshire. The country between the coal-fields of Coal Brook Dale and Staffordshire, of which Shifnal is the centre, is also occupied by deep red thick-bedded sandstones, lying in a trough. (See Section, Pl. 29, fig. 13.) These central rocks of the system, further extend over all the wide tract between Stourbridge and Kidderminster, constituting for the most part a rye-land district. The blood-red soft sandstone of the latter town is a good type of ' These meres are supported by thin courses of marl, or superficial detritus. 42 CONGLOMERATES OF RED SANDSTONE. them, being nearly free from mica, with occcasional partings of brown slightly mica- ceous marl. Some of the lamine are filled with very minute grains of coal derived from the adjacent fields, the whole reposing on the calcareous conglomerates of Horsley Bank, which belong to a subjacent part of the system. (See Pl. 30. fig. 3.) In Worcestershire, as in Shropshire and Cheshire, the Saliferous Marls underlie the Lias, and pass downwards into larger masses of sandstone which rise at a very gentle inclination into hills west of Droitwich, and extend to Ombersley and Hartlebury, where the rock is a finely grained, argillaceous sandstone, slightly calcareous in parts, of a dull red colour, with, occasionally, spots of green, blue and white. The sandstone in the adjacent parts of this district (Bromsgrove, &c.) agrees so closely, that it is unnecessary to repeat the description of it at other localities in Worcestershire. Besides, the tract is for the most part so much covered with gravel, as to render it difficult to assign precise geographical boundaries to this subdivision. In the tract between Kidderminster and the Clent Hills, in the hills he the Dudley coal-field, and again in the district ranging far to the north in Staffordshire, the central sandstones contain beds of conglomerate, chiefly filled with rounded pebbles of quartz rock’. The pebbles vary in dimensions from the size of a child’s head to that of an almond, consisting chiefly of white and pink quartz, with others of Silurian rocks and Old Red Sandstone ; the whole subordinate to, and inosculating with thick beds of deep Red Sandstone. The quartzose conglomerates occupy a great number of hills, the surfaces of which are usually much disintegrated, and hence they have afforded much of that detritus which has been spread over so large a part of the low country of Worcestershire and around the Clent and Lickey Hills. (See the conclud- ding chapter on Gravel.) Numberless sections, however, expose these rounded quartz pebbles, imbedded in the Red Sandstone at different localities over an immense area, extending by Wolverhampton to Cannock Chase, and spreading from Birmingham on the east, to near Bridgenorth on the west, and thence into North Salop ; but detailed sections of quarries, in which nearly all the materials are alike, whether near the Bar Beacon, at Himley, Wolverhampton, or at Hodnet, would only fatigue the reader and convey no real instruction, In some situations, the uniform character of these conglo- merates is varied by the addition of a few pebbles and fragments of the Cambrian, Silu- rian, and Carboniferous systems, including trap rocks. Instances of this sort occur between Bridgenorth and Wolverhampton, but it is doubtful whether some of these beds may not rather be classed in the inferior divisions of the New Red System. There is a prodigious accumulation of quartz pebbles, resulting from decomposed New Red Sandstone, at Wallsall, where they cover indiscriminately Silurian limestones, and coal measures ; indeed, in this and many other parts of the coal-field of Staffordshire, 1 Good sections of these beds are exposed on the sides of the road from Stourbridge to Kidderminster. In some of the red sandstones near the Lickey, grains of black oxide of manganese are disseminated, as in the sandstones of Shropshire. (p. 38.) ORGANIC REMAINS OF THE NEW RED SANDSTONE. 43 it is often difficult to determine, whether the New Red Sandstone is there in situ, or whether the surface is merely covered by its disintegrated materials. (See Section, Pl. 37. fig. 3.) Animal organic remains have not yet been recognised in this division of the New Red System in Great Britain, but in a rock of the same age at Rhone Hill near Dun- gannon in Ireland, a profusion of small fishes (Pal@omiscus catopterus' of Agassiz) were recently discovered. Although I have little doubt that future researches will bring to light fossil vegetables from the central masses of our New Red System, I am as yet acquainted with one plant only, found in strata of this age at Liverpool, a specimen of which is in the Museum of the Literary and Scientific Institution of that town, and was, at my request, recently submitted to the inspection of Professor Lindley, who has figured it in the Fossil Flora, vol. iii. t. 201. naming it Dictyophyllum crassinervium. The accompanying wood-cut is taken from the drawing prepared under Mr. Lindley’s direction, and he thus describes the fragment. ies) ‘The specimen is that of a leaf of considerable size, of which only a portion of the upper end remains, the end itself and all the margin being broken off. It bears a striking resemblance to the leaf of some of the thick-ribbed cabbages, consisting of several elevated ribs, full three quarters of an inch wide, which spring at an acute angle from a midrib of about the same thickness, and divide towards the point into two or three 1 Geol. Proc., 1834-5, vol. ii. p. 206. The fish quarries of Rhone Hill were visited by Professor Sedgwick and myself, accompanied by Mr. Griffith, Lord Cole, and Colonel Montgomery. 44. ORGANIC REMAINS OF THE NEW RED SANDSTONE. branches, besides in one place putting out lateral ribs near the base. Intermediate to the principal ribs are, in one place transverse connecting elevations, which we may suppose to have been secondary veins; and in another place a small vein with lateral veinlets. In the whole specimen there is a good deal of irregularity of arrangement in the parts, and a greater want of symmetry than is usual in leaves.” Although the Upper Formations of the New Red System in England afford few traces of fossil plants and animal remains, the strata of the same age in France and Germany contain a flora and fauna of peculiar character. Many of the plants are already figured by M. Adolphe Brongniart, in his great work on fossil botany, ‘‘ Histoire des Végétaux Fossiles.””> The Keuper, for example, presents several species of Equisetacee of the genera Calamites and Equisetum, and a fern of the genus Pecopteris. The Muschelkalk contains a species of fern, Neuropteris, and Mantellia, one of the Cycadee. In the Grés bigarré the following plants occur. EaquisetacEa: Equiseti and Ca- lamites. Fintices: Anomopteris, Neuropteris, Sphenopteris, and Filicites. CONIFERH: several species of that remarkable genus Voltzia, named after the geologist whose la- bours have thrown so much light on the structure of Alsace’. Littacrm: Convalli- rites, Aithophyllum, Paleoxyris, Echinostachys. On the whole, these plants have a certain community of character peculiar to the deposits of this age, and are very distinct from the vegetables of the overlying or underlying systems. One plant only of the Keuper, Equisetum columnare, is found in the lower part of the Oolitic System ; whilst two species, Calamites arenaceus and C. Mougeottu, are common to the Keuper and the Grés bigarré. Some of the animal remains of the Keuper have already been mentioned (note, p. 30. &c.). In the Grés bigarré, besides the saurians, to which I have alluded, there are univalve and bivalve shells, some of which are well-known fossils of the Muschelkalk. In a masterly sketch of the red sandstone group of the Vosges and adjacent parts of France’, M. Elie de Beaumont has shown that the upper marls (Marnes irisées), which he places in parallel with our English red marl, are the true representatives of the Keuper; and the identity between these marls of Lorraine and the Keuper of Swabia has lately been completely established by M. Levallois*, who coincides with De Beau- mont and Voltz in considering the whole formation to be composed of saliferous and sypseous marls, with occasional traces of coal and thin subordinate courses of sandstone and limestone. Thus the Keuper of Lorraine and Swabia only differs from our red marl in containing traces of coal and limestone, with bands of sandstone of greater thick- ness than any known in the English formation. In these regions, however, there is no ambiguity, since the Keuper is surmounted by the Lias, and is invariably separated 1 Géognosie de l’Alsace. Strasbourg, 1827. 2 Mémoires pour servir 4 une Description géologique de la France, tome i. p. 1. 3 Mém. de la Soc. Géol. de France, tome ii. p. 1. COMPARISON WITH FOREIGN NEW RED SANDSTONE. 45 from the Grés bigarré by the Muschelkalk ; but in the central and south-western parts of France, as the researches of M. Dufrénoy* acquaint us, the upper marls and under- lying sandstones are brought together, precisely in the same manner as in England, the Muschelkalk or subdividing limestone having thinned out. _ Judging from these comparisons of foreign types, I have no doubt that our saliferous marls in England, with their subordinate courses of sandstone, represent the Keuper and Marnes irisées ; and whether or not the calcareous course of Broughton in Shrop- shire be ultimately referred to the Muschelkalk, still it appears certain, that all the massive sandstones underlying the marls, as described in this chapter, are the true representatives of the Bunter Sandstein or Grés bigarré; for independent of clear stratigraphical position, the great thickness and indivisibility of these sandstones seem to me distinctly to authorize this conclusion. ) 1 Mém. pour seryir, &c. tome 1. p. 313. CHAPTER LV. NEW RED SYSTEM. (CONTINUED. ) 3. Calcareous Conglomerate.—4. Lower New Red Sandstone. 3. Calcareous Conglomerate.—Kquivalents in England: Dolomitic Conglomerate, Magnesian Limestone.—Foreign Equivalent: Zechstein. THE rocks forming the third division of the New Red System in the central counties, must, from their position, be considered of the same age as the Magnesian Limestone of the North-east, and the Dolomitic Conglomerate of the South-west of England. (d. of wood-cut 5, p. 28.) They do not, however, contain solid beds of magnesian limestone, and very seldom so much magnesia as to entitle them to the name of dolomitic conglo- merate ; but are, for the most part, simply calcareous conglomerates, consisting of frag- ments of quartzy, Silurian, and other rocks, as well as of carboniferous and other lime- stones, enveloped in a calcareous matrix. In the Tortworth district, at the northern extremity of the Bristol coal-field, the true dolomitic conglomerate is considerably developed, and has been fully described by several geologists’. In the North of Gloucestershire and South of Worcester, where the the New Red Sandstone is conterminous with the Old Red, there are no distinct traces of this member of the series, unless we suppose that the few thin courses of slightly calcareous conglomerate, which occur, at intervals, near the bottom of the sandy series, be its representative. (See p. 51.) In the great expansion, however, of the New Red System in the North of Worces- tershire, in Staffordshire, and Shropshire, there are calcareous conglomerates of con- siderable thickness, which, as they pass beneath the great masses of Red Sandstone already described, there can be no hesitation in referring also to the age of the Mag- nesian Limestone. They occur in great force in the north-eastern face of the Lickey 1 See the memoirs of Mr. Horner, Dr. Bright, Mr. Warburton, Messrs. Buckland and Conybeare, and Mr. Weaver; Geol. Trans., vol. iii. and iv. Old Series, and vol. i. New Series. This dolomitic conglomerate is also described in this work in the chapter on Tortworth, and the position is marked near the south-eastern extremity of the accompanying map. CALCAREOUS CONGLOMERATE IN WORCESTERSHIRE. 47 and Clent Hills, and appear also on the northern end of the Lickey ridge of quartz rock, whence they range by St. Kenelms to Hagley. In this course they distinctly overlie a great formation hereafter to be described as the Lower New Red Sandstone, and rise high on the sides of the trap rocks of the Clent Hills. They here vary much in im- portance, particularly near St. Kenelms and Hagley (see Map), some masses having a thickness of fifty and sixty feet, others of not more than six or eight. At Gannow Green, near St. Kenelms, there are extensive lime-works in this rock, an account of which may suffice for those at other localities. The beds dip very slightly to the south, and are separated from each other by sandy marls and clay. The greater part of this rock is made up of angular fragments of a pre-existing, very compact limestone, which, from the corals and other fossils found in it, proves to be the carboniferous limestone. In some parts of the quarries the rock consists of concretions of marl and fragments of sandstone and grits with coal plants, imbedded in a pink calcareous grit ; but in others, of small pebbles of quartz and still older rocks, enveloped in a red, ferruginous, earthy basis, penetrated in all directions by white, crystallized carbonate of lime. The matrix and cement are throughout very calcareous, and the colour of the rock varies with that of the ingredients, from a reddish tinge, to shades of yellow and white. This conglomerate follows all the sinuosities and pro- montories of the Clent Hills, as is well seen between the hills of Romsley and Walton, where, associated with the Red Sandstone, it enters into a deep recess. It also folds round Hagley Park (near the parsonage), accommodating its outline to the form of the hills, where it has been described by the Rev. J. Yates as a calcareous breccia, consist- ing of grains of quartz, decomposing felspar, and limestone’. Transverse sections, from north to south across the strata, are exhibited on the sides of the roads which ascend to the Clent Hills by St. Kenelms, or by Hunnington (see Pl. 29. fig. 10.), and expose several lower calcareous courses, separated by argillaceous red marls and sandstone. Calcareous bands prevail so much in this district, re-occurring at intervals in the escarp- ments through a thickness of many hundred feet, that if they were all included in this division it would be impracticable to define with precision their limits, since they gra- duate into, and form a part of the Lower Red Sandstone, which in its turn overlies and passes into the coal measures. (Quarry Hill, Hales Owen, Colmer’s Hill, Hodge Hill, see Pl. 29. fig. 10.) It will indeed be shown in the sequel, that other calcareous bands, for the most part, however, of true concretionary structure, are even traceable down into the coal measures ; and for this reason I restrict the comparison with the Magnesian Limestone or Dolomitic Conglomerate, to the mass of this rock which immediately lies beneath the central sandstones (Bunter Sandstein, or Grés bigarré.) Calcareous conglomerates are to be seen at many points round the outline of the Dudley and Wolverhampton coal-fields, generally at some little distance from the edge of 1 Geol. Trans. vol. i. p. 250. F2 48 CALCAREOUS CONGLOMERATE IN SHROPSHIRE. the coal-bearing strata, and always dipping away from or overlying them; Brand Hall on the east, and Himley and Tettenhall on the west, may be cited as localities. To the north of Kidderminster the bold escarpments of the New Red System, contain calca- reous conglomerates which are burnt for lime at several places, between Enville on the south and Coton on the north. At Coton and at Bowells, the rock is from twenty to thirty feet thick, and is composed of the following varieties : (a.) Coarse Conglomerate, composed chiefly of fragments of carboniferous limestone, generally rounded and red on their exterior. Some of them are of an oolitic structure; others of a compact limestone, containing encrinites, corals, and terebratule, and discoloured partially by films of green carbonate of copper. (b.) Conglomerate, with fewer fragments of limestone but pebbles of quartz, Old Red Sandstone, &c.; the whole cemented by pure white, crystallized carbonate of lime. _ This conglomerate passes into a pink calcareous sandstone with pebbles and minute fragments of jasper. In attempting to refer the fragments of limestone to the original rock, the oolitic structure distinctly proves, that some of them have not been derived from any formation below the Old Red Sandstone, in none of which has such a structure ever been observed, whilst the nearest known masses of a similar rock, are in the carboniferous limestone of the Clee Hills, twenty miles distant. The included fossils belong likewise to the same deposit. The rolled condition of the fragments also accords well with the belief of their having been drifted from the Clee Hiils. Calcareous conglomerates, inclosing pebbles of felspathic trap rock, form the cap of the hills on the left bank of the Severn opposite Bridgnorth, and they are found in the continuation of this ridge in Apley Terrace. At the north-eastern extremity of the Coalbrook Dale coal-fields, similar rocks occupying precisely the same geological position, are found in Nedge Hill; and again, to the east of Lilleshall Abbey, where the new mansion of the Duke of Sutherland is actually built upon them. At this point the underlying strata consist of the Lower Red Sandstone, the overlying of the ordi- nary red sandstone described in the last chapter. (See Pl. 29. fig. 15.) The conglomerate in this neighbourhood is not sufficiently calcareous to be burnt for lime, being chiefly composed of rounded pebbles of sandstone and quartz with some fragments of carboniferous limestone in a base of quart- zose and calcareous sand'. Here, as in other localities before mentioned, the strata dip away from the adjacent coal-field, from which, as we shall afterwards perceive, they are separated by a great fault. (See Pl. 29. fig. 15.) The extensive denudation of the whole series of the New Red System between Newport and Shrewsbury, has obliterated all traces of these calcareous conglomerates, and they are not met with again till we reach the banks of the Meole Brook, about two and a half miles south of Shrewsbury, where a small face of the rock can be seen which was formerly quarried to burn into lime, but it is rapidly lost, dipping at about 30° under the overlying Red Sandstone. To the south and west of this spot, the relations of the various members of the New Red System which overlie the coal-bearing strata of Pontesbury, &c., are much obscured by a thick cover of coarse gravel and clay; but at Cardeston the calcareous conglomerate again rises to the surface. From Cardeston to Alberbury the rock is displayed for nearly two miles, constituting a low ridge, which presents its escarpment to the carboniferous tracts of Wolliston, &c., whilst the upper surface dips away to the north and east, and passes beneath the 1 The hardness of the rock is such that the workmen call it the ‘‘ Devil’s haster.” SHELL MARLS OF THE MAGNESIAN LIMESTONE. 49 Red Sandstone north of the Severn, Ness Cliff, &c., (see section Pl. 29. fig. 9."). The central or most calcareous part of this ridge, has been quarried through a thickness of about thirty feet, the beds dipping at an angle of 15°. The strata consist of angular fragments of compact, cream-coloured limestone (the ‘‘ kernels” of the workmen) in a reddish, sandy, calcareous matrix, in which small cavities occasionally occur, lined with crystals of dolomite. Limestone containing magnesia, is abundant in some beds of the mountain or carboniferous limestone at Llanymynech and Porth-y-wain, distant only a few miles, and that rock being of older date, may have supplied many of the inclosed materials, and much of the cement of this conglomerate. Some frag- ments of limestone, occasionally as large as a man’s head, and forming a part of the conglomerate, have, however, been derived from the breaking up of a peculiar fresh- water limestone which is intercalated between the seams of coal in the adjacent carbo- niferous tracts of Coedway, Pontesbury, &c. (See Chapter 5.) Besides the calcareous fragments, there are small, rounded pebbles of white quartz and other ancient rocks. These additional materials become more abundant as the ridge sweeps round to Loton Park, and they are well exposed in a section on the high road from Shrewsbury to Llanymynech, where the strata dip 8° to 10° to the east. The calcareous layers, though here subordinate to sandstone, reappear at intervals through a thickness of at least 120 feet, and overlie the thick-bedded red sandstones which form the base of the whole system. This section at Loton (Pl. 29. fig. 9.) is therefore a clear and convincing proof of the true position of the dolomitic conglomerate, since it is evidently separated from the underlying coal of Coedway by the Lower Red Sandstone of Pecknell. In the chief lime quarries of the Alberbury ridge, were formerly some slight mining trials, occasioned by finding a few thin strings of copper ore. ‘These strings were in the vertical joints of the rock, ranging from south-south-west to north-north-east, or nearly at right angles to the direction of the strata. The sides of these joints are asually faced with upright bands of hard sandstone, termed ‘‘ Burrs,” which cut through the strata and are enemies of the lime-burners. Although it has been stated in the previous pages, that no remains of shells have yet been detected in the overlying members of the New Red System of England, a consider- able number of curious and unpublished species, have recently been discovered at Man- chester, in beds of variegated marl?. These shelly marls are considered by Professor Sedgwick to lie beneath the upper and central members of the New Red System; and Professor Phillips, who has recently worked out in some detail the relations of the strata in the environs of Manchester, is of the same opinion. In a letter to myself, he ' This calcareous conglomerate of Alberbury has been fully described by Professor Sedgwick, and recognised by him as the true equivalent of the magnesian limestone, and its relations to the lower red sandstone established. Geol. Trans. vol. ii. p. 399. 2 Mr. Leigh and Mr. Binney of Manchester discovered these shells, as announced in a communication which they forwarded through myself to the Geological Society. 50 BASE OF NEW RED SYSTEM, GLOUCESTERSHIRE. describes these shelly marls as lying between the formation No. 2. of the last chapter, and the Lower Red Sandstone, and consisting of red-coloured marls, with thin-bedded, yellow or reddish mottled limestone, both concretionary and granular. ‘‘ I view them,” he adds, ‘‘as attenuated and deteriorated magnesian limestone, the last term of the degradation of this rock.” From the observations, therefore, of Professors Sedgwick and Phillips, there can be no doubt, that the Manchester shelly beds are of the same age as the calcareous and dolomitic conglomerates of Salop, Worcester and Stafford, which are the equivalents of the Magnesian Limestone. These marls must be regarded with great interest, as links connecting those peculiar types of the lower New Red Sandstone described in the concluding part of this chapter, with strata of the same age in the North of England, which are known to geologists through the labours of Professor Sedgwick. Among the shells from the marls at Col- lyhurst, Professor Phillips recognises Awinus obscurus, M. C., or a large variety of that species, as the most prevalent, associated with an Avicula, not very remote from A. sociahs of Schlotheim; and many small undescribed univalves. The same author holds out the prospect of publishing a monograph of the fossils of the magnesian limestone, including all the species in the Manchester marls. Having now described the three upper divisions of the series in those districts, where their characters and order of superposition are distinct, I might at once proceed to the examination of the subjacent sandstones, where they are most expanded, as around the coal-fields of the central counties. It is desirable, however, previously to invite atten- tion, to the prevailing characters of the lower portions of the system, in Gloucestershire and the West of Worcestershire, where the system being little developed, the whole of its lower portion, consisting of conglomerates and sandstone, is so intimately connected, that it can be considered only under one head. Base of the New Red System in Gloucestershire and south-western parts of Worcestershire. In Gloucestershire and the adjacent part of Worcestershire, the members which con- stitute the bottom of the system, are sandstones and conglomerates of mixed characters, sometimes slightly calcareous, at others quartzose, and occasionally containing great abundance of pebbles and fragments of trap rock, intermixed with sedimentary rocks of high antiquity. Such beds may represent either the central Sandstones and Quartzose Conglomerate No. 2, or the Calcareous Conglomerate No. 3, or the Lower New Red Sandstone No. 4. _ This view is rendered probable, by the gradual expansion of the respective members of these deposits in their range from south to north, until they attain that great development, which constitutes the New Red System of the northern parts of Worcestershire, Stafford- shire and Shropshire. Having personally traced the line of demarcation between these BASE OF NEW RED SYSTEM, GLOUCESTERSHIRE. a red formations and the older rocks on which they rest, from Chepstow to Denbighshire, I commence by pointing out the manner in which, from small beginnings in the south, their successive development is accomplished as we proceed northwards. In the tract between Chepstow and May Hill, the whole of the space coloured on the map as be- jonging to the New Red System, is exclusively occupied by the upper red and green marls, (not saliferous in that tract,) which are seen at many points in contact with Old Red Sandstone, and at Flaxley with Silurian Rocks. (Pl. 36. fig. 13.) At Huntley on the eastern side of May Hill, soft red sandstones first appear, rising from beneath the marls and separating them from the Silurian rocks ; and between that place and Newent, where the sandstone attains a considerable thickness, there are traces of quartzose conglomerates occasionally cemented by calcareous matter. These re- lations prevail for some miles to the north of Newent, the lower beds of the system overlying a thin zone of coal measure; but in approaching the Malvern Hills, the sandstones are much more ex- panded, and the conglomerate near their base is of greater importance, and of different lithological composition. : In the absence of natural sections, the presence of the sandstone above the conglomerate (Grés bigarré), is clearly indicated by the “Rye Land” or sandy loams, which uniformly give a dry agricultural character to the surface of all the tracts occupied by that member of the system. Between Huntley and Lyne’s Place are good sections of the sandstone, arranged in fine-grained, friable, thickish beds, of deep red colours, and containing subordinate, irregular courses of a small conglomerate, in which are fragments of the old red sandstone and inferior rocks. Some of these conglomerates are slightly calcareous, others pass into mere grits, the whole resting upon and thinning out, in light-coloured, incoherent sand, Low Hill, west of Lyne’s Place, affords a clear section of these beds dipping 25° to 30° to the east, a high degree of inclination for the New Red Sandstone, though similar examples will be mentioned in following the lower beds of the system. From May Hill to Haffield Camp, near Ledbury, these rocks, with the exception of the tract near Newent, are in contact with the Old Red Sandstone; and the line of separation is defined by the nature of the surface. In some spots near Newent, the demarcation is pointed out by actual sec- tions, exhibiting thin patches of coal-measures, interpolated between the New and Old Red Sand- stones. At Pitleases, Weatherlocks, and Oxenhall, the sandy rye lands rise into eminences based upon red conglomerate and sandstone; and at the escarpment is a thin profitless zone of coal, resting upon the stiff clays of the Old Red System. In one instance, however, the new red conglo- merate dipping 15° to the south-east, lies at once upon the edges of micaceous flagstones of the Old Red, which are thrown up at an angle of 70°. (Pl. 30. fig. 10.) | Clear junctions of the New and Old Red Systema are exhibited at Broom’s Green and at Haffield Camp. (Pl. 29. fig. 1.') At the latter place, the upper beds of the New Red consist of soft, red sandstone, and the lower of brecciated conglomerate, of a deep red colour, containing fragments of syenite, varieties of Silurian rocks, quartz rock, and Old Red Sandstone. The syenite derived from the adjacent ridge of Malvern is in much 1 The section displaying these beds of new red conglomerate was laid open only two years ago at Haffield Camp, the quarries being south of the high road from Gloucester to Ledbury. ‘Some of the fragments or syenite are of the size of turkey eggs, varying from that to the size cf almonds. ‘The stone is extracted for walling, and to use the expression of the workmen, “it hugs the mortar well.” 52 BASE OF NEW RED SYSTEM WEST OF WORCESTER. greater abundance than the other materials, and gives the mass a trappean character, resembling that of the well-known Heavitree conglomerate near Exeter. The beds dip south-south-east 18°, but the argillaceous and sandy strata of the Old Red System on which they rest, are inclined in an opposite direction. Deep red, thick-bedded, soft sandstones occupy all the country about Redmarly-Dabitot, wrap- ping round the southern edges of the Ledbury and Malvern Hills ; but there is, here and there, (Bromesbarrow) a trace of an underlying conglomerate. Towards the east, these red sandstones pass beneath the red and green marls (Keuper) described in the preceding pages. The base of the system is ill exhibited along the eastern flanks of the Malvern ridge, being deeply denuded, and overspread by much detritus. It has been already stated that the marls of the formation are here much developed ; they are indeed prolonged so far to the west that a small space alone is left for the sandstones.. This is well seen on the road from Tewkesbury to Ledbury. The red sandy and conglomerated beds are, however, visible in one or two spots, at and near Great Malvern, on the upper side of the main road, adhering to the steep slopes of the syenite. A farm-yard north of the Foley Arms, has been excavated in the surrounding rock, which on one side of the yard is a soft deep red sandstone, with a thin band or two of fine conglomerate’, the beds dipping 35° east-south-east ; on the southern side the section is less clear, owing to dislocated masses of red and green marl, which are subordinate to the sandstone, but apparently the inclination is equally high. The inference to be drawn from this high inclination of the beds of the New Red Sandstone, at a height of four to five hundred feet above the plain, will be pointed out in the chapter upon the Malvern Hills. The foundations of many of the houses along the lower terraces of Great Malvern, are excavated in the deep-red sandstone which overlies the fine conglomerate ; but the succession of strata, in as- cending order, cannot be accurately observed, owing to superficial detritus. Between Great Mal- vern and Worcester the marly or upper division of the New Red System (Keuper) is much expanded, occupying the Old Hills and Madresfield, and overlying the red sandstone we have been consider- ing. ‘To the west and north-west of Worcester these marls are much obscured by gravel, and it is only near the base of the system that we can observe the true relations of the strata, which are occasionally exposed, resting on the ridge of Silurian rocks which connects the Malvern with the Abberley Hills. The banks of the Leigh Brook where it issues from the Silurian ridge, north-east of Old Storridge Hill, afford good natural sections of dark red, thick-bedded sandstone, and the sides of the deeply channelled lane ascending towards Patches farm, expose bedsof a brecciated conglomerate, dipping at a high angle to the north-east. The chief ingredients of these beds are angular fragments of old rocks, especially of the shelly Caradoc sandstone of the adjoining hill of Old Storridge. They are occasionally imbedded in a red and green calcareous cement, and layers of red and green marl sometimes occur, subordinate to the sandstone and conglomerate. The line of demarcation of the New Red from this spot towards the north, follows the sinuosities of the Silurian ridge, but rises in certain spots, as at Great Malvern, some hundred feet above the plains of Worcester. Between Ravenshill Green andBate’s Bush, is a light green, flaggy, micaceous marlstone, with a little gypsum and in the high lands to the north, some of the beds of red and green marl, which overlie the zone Deane eee eee eee ee eee ee 1 The fragments in this conglomerate vary from the size of walnuts to peas. They consist chiefly of ancient depository rocks and Old Red Sandstone. Syenite is rare in it, and the fragments are small and angular, BASE OF NEW RED SYSTEM WEST OF WORCESTER. 53 of sandstone are highly inclined. At Black’s Well, near Knightwick, where the Silurian rocks subside for a short interval, are extensive quarries of a lightish red sandstone, speckled with yellow grains, and of a very superior quality. This thick-bedded, though finely laminated sandstone, dips 18° south-east; the angle of inclination having decreased with the depression of the ridge of older rocks against which it rests. Almost adjoining the sandstone of Black’s Well, and constituting the southern side of the gorge at Knightsford Bridge, through which the Teme escapes from Herefordshire into the plains of Worcestershire, is a remarkable cliff called ‘‘ Rosemary Rock,” the summit of which is about three hundred and fifty feet above the sea. At this spot, the Old Red and New Red Sandstones are again conterminous, being separated by only an alluvial meadow. (See Section Pl. 29. fig. 4.) The northern face of Rosemary Rock, is the finest vertical section of the coarse conglomerate near the base of the new red, with which I am acquainted. The fragments vary from a large size to that of almonds, and are both rounded and angular; the greater number and largest, consisting of a purple coloured, concre- tionary trap, hereafter to be described, which occurs in the hills of Barrow, Woodbury, and Abberley, the northern prolongation of the Malvern ridge. ‘The other fragments are chiefly referrible to the Silurian system, and among them are quartz rock, indurated schist, and other altered rocks. The cement is partly calcareous, with a few veins of white calcareous spar. On a hasty inspection, this rock and others resembling it along this chain of hills, (as at Haffield Camp described p. 51,) might be mistaken for the trap rocks, from which they have been partly derived, but the admixture of fragments of stratified rocks of the Silurian and Old Red Systems, distinctly proves its regenerated character. The summits of those hills lying to the north of the Teme, which are marked in the map as trap, exhibit, on the contrary, no fragments except those of a peculiar rock, predominant in this range and in the Clent Hills. At Collins Green, conglomerates like those of Rosemary Rock, associated with beds of deep red sandstone, rise to the same height as the ridge of Silurian rocks, from the flanks of which they dip 20° to 25° south-east. In this conglomerate are also many portions of silicified schist, quartz rock, and altered Silurian rock. The Silurian and trap rocks subsiding to the west of Martley, the New Red Sandstone is again conterminous with the Old, and with the depression of the older and intrusive rocks, we find a corresponding absence of coarse conglomerate and trappean fragments; the deep-coloured, thick-bedded sandstone of Martley, being nearly free from all pebbles and foreign fragments. In the north-western parts of Worcestershire, the New Red System begins to expand; and con- glomerates, such as those described, are partially underlaid by soft red sandstone, both on the eastern flanks of Walsgrove Hill near the Hundred House, and at the termination of the Abberley Ridge (the Round Hills). Thence to the north, the boundary line of the New Red Sandstone comes in contact with the stiff clays and flagstones of the Old Red, but within two miles of Bewdley, it begins to flank the coal measures; and other examples of the angular coarse trappean conglomerate or breccia occur, the fragments of G 54 LOWER NEW RED SANDSTONE. trap having been derived, it is presumed, from Stagbury Hill. A similar rock is found at Warshill on the left bank of the Severn, also rising up on the edge of the Lower New Red where it is bounded by the Old Red Sandstone, the conglomerate being interposed between the intrusive rock and the soft sandstone of Kidderminster’. The same conglo- merates, subordinate to, and winding through masses of thick-bedded sandstone, are in- structively displayed at Winterdine, near Bewdley; and contain fragments of coal-measure grits and concretionary trap, both of which rocks being in situ adjacent to the conglomerate are of angular forms, whilst the quartz and pebbles of older rocks, which have been trans- ported from greater distances, are rounded. These strata are unconformable to the ad- joining sandstone and grits of the coal measures, and pass beneath the red sandstone, which forms the cliffs on the left bank of the Severn, and ranges to the town of Kidder- minster. (Pl. 30. fig. 2.) I have thus attempted to show, that to the south of Kidderminster and Bewdley the lower limit of the New Red System is usually marked by certain conglomerates re- sembling those of Devonshire, which I agree with Professor Sedgwick® in considering as distinct from the Lower New Red Sandstone or Rothe-todte-liegende. We may, therefore, proceed to the consideration of the structure of these tracts where natural sections exposing a full development of the lower members of the system, exhibit, be- sides the calcareous and other conglomerates before described, the Lower New Red Sandstone as a great and distinct subjacent formation of sandstone, marl, and shale, with subordinate courses of impure concretionary limestone, the whole passing down gradually into the carboniferous system. | 4. Lower New Red Sandstone.—Foreign Synonyms: Rothe-todte-liegende (Ger.), Gres des Vosges—couches inférieures ? (Fr.) When fully developed, as in the tracts of Worcestershire, Staffordshire and Shropshire where I shall now describe it, this formation differs essentially in lithological structure from any rocks we have previously considered. (e. of wood-cut 5, p. 28.) Asa mass it may be said to consist of sandstones and grits, chiefly of a red colour, sometimes argillaceous, very frequently calcareous, associated with deep brown red shales and marls, occasionally spotted green. Grains of whitish, decomposed felspar, are frequent in a matrix of dull 1 The trap rocks of Stagbury and Warshill are similar to those of Abberley and the Clent Hills. (See subsequent account of similar rocks in the coal-field of the forest of Wyre, chap. 9.) | 2 See Professor Sedgwick’s view of the Red Conglomerates of Devonshire, Geol. Trans. vol. iv. p. 383 et seq. Since that memoir was printed, Professor Sedgwick and myself have visited Devonshire, and our opinions are expressed in the concluding part of this chapter. LOWER NEW RED, NORTH WORCESTER. 55 red sandstone, iron in various states is here and there disseminated, and bands of impure concretionary and mottled limestone re-occur at various levels. ‘Towards the base, many fragments of impressions of plants appear in beds of sandstone, which graduate into other and lower strata, containing thin seams of coal, from which there is a conformable de- scending passage into the true carboniferous system. (f. of wood-cut 5, p. 28.) In general these rocks contain much argillaceous matter, which on decomposing gives a striking resemblance in the surface of the country, to those tracts which are occupied by the Old Red Sandstone; whilst some of the calcareous bands above mentioned, are associated. with hard flagstones. So completely, indeed, do these bands resemble the cornstone of the Old Red Sandstone, that they were formerly described from a part of this very tract as belonging to that formation’. There is now, however, no doubt respecting their age, since besides their clear superposition to the coal measures, some of these beds contain fragments of mountain limestone, and sandstones with coal plants. This is one of the many proofs (ample testimony of which will be found throughout this volume,) of the danger of testing the age of rocks, by any peculiarity in their mineral character, however striking; for the graphic description of the cornstone of the Old Red Sandstone, given by Dr. Buckland, is derived from specimens now proved to belong to the New Red System. I cannot, however, make this observation without remarking, that the mere lithological character of many of these beds might still mis- lead the most practised geologist, if he had not worked out the relations of all the other rocks of the district*. Upon the eastern face of the Clent Hills, the Lower New Red appears as a highly argillaceous red sandstone, underlying the chief bands of calcareous conglomerate of Frankley and Gannow Green, and dipping away from small patches of coal, on the north-eastern face of the quartz rock of the Lickey Hills, and at the southern end of the great Dudley coal-field. (See section, Pl. 37. figs. 7 and 8.) There is distinct proof in both tracts, that the Lower Red Sandstone is conformable to, and passes into underlying coal measures; but as the latter are of very poor quality, and are in fact mere layers of carbonaceous matter, they have in most instances not been wrought, whilst in others where they have, the works being abandoned, the relations are but little known. It is certain, however, that to the east of Rubury Hill (Lickey), the strata dip to the east at a slight angle, and pass with apparent conformability 1 Geol. Trans., Old Series, vol. v., note p. 512. In my own case, for example, I am bound to acknowledge, that misled by mineral characters in the first year of my survey, I laid down an adjacent tract of the Lower New Red, as Old Red Sandstone, an error which I only rectified by working out the relations of all the surrounding rocks. Mr. Greenough in the table of superposition illustrative of his map, has noticed the occurrence of cornstones both in the New and Old Red Sandstone. It may be stated, that the inhabitants make no distinction between the half-concretionary, half-conglomerate cal- careous masses in the New, and those in the Old Red Sandstone. In the country, however, of the Old Red Sandstone, the name of ‘‘ Cornstone”’ is restricted to the coarse, sandy, ee masses, and is never applied to the large concretions of purer limestone. Goa 56 LOWER NEW RED, WORCESTERSHIRE AND STAFFORDSHIRE. beneath the Red Sandstone. Between Hales Owen and Hagley, at Wassall Grove and Lutley, poor coal seams are apparent in natural sections, forming the lowest portion of this system, or top of the carboniferous strata, and dipping beneath the conglomerate and red sandstone of the St. Kenelms and Clent Hills. (See Pl. 29. fig. 10.) Among the most instructive excavations opened in these rocks, are those of the Quarry Hill south of Hales Owen, where thick-bedded, red, gritty sandstones, both soft and hard, are extracted for troughs, slabs, and building purposes, and contain irregular thin seams, filled with minute fragments of coal; whilst lower beds rising from beneath, pass into layers of hard grey grit, in parts calcareous, their surfaces being covered with fragments of coal and impressions of stems of plants. From these beds, there is a gradual passage into the coal tract of the neighbourhood of Hales Owen. At Coleman’s Hill and Hodge Hill, in the same district, there are other sections, the strata in which, though differmg somewhat in mineral characters, belong to this lower division of the New Red System ; and these also exhibit passages into the coal measures. At Cole- man’s Hill, the upper beds consist of yellowish, soft, gritty sandstone, containing some small calcareous fragments, a few pebbles of quartz, blotches of red shale, and frag- ments of sandstone with impressions of stems of plants’. This sandstone graduates into thick-bedded calcareous grit, spotted with bluish grey, black and yellow colours, and partially burnt for lime. The spotted appearance is due to fragments of coaly matter, mixed with imperfect concretions of crystallized carbonate of lime and blotches of ochreous decomposing sandy matter. The sandstones of this age occupy a distinct ridge from Hodge Hill by the Two Gates, to near Hales Owen. ‘They are for the most part of a yellow colour, are very cellular, and are not unlike portions of this part of the system in the county of Durham, which Professor Sedgwick has identified with the rothe- todte-liegende. JI allude particularly to the soft, white, yellow and red sandstones on the banks of the Wear, at Clacks Heugh, &c., near Sunderland. On the sides of the gulleys, poor and thin seams of coal are exposed; and one of them occurring in grey calcareous breccia, similar to that of Coleman’s Hill, is made up of fragments of coal sandstone, schist, and limestone, in a calcareouscement. In the bed of a brook under Wassall Grove, I observed a seam of this coal three to four inches thick, overlaid by what may be termed a carboniferous cornstone, somewhat resembling that of Coleman’s Hill, and containing small interspersed fragments of bituminized vegetable matter, rounded and apparently water-worn, like the pieces of drifted wood seen upon the sea-coast. The calcareous bed passes upwards into thin-bedded, brownish yellow sand- stone, weathering to a reddish colour. In the fine natural sections seen as we descend 1 Mr. W. Hamilton, then Secretary to the Geological Society, accompanied me in one of my visits to the district around Hales Owen, and he can bear witness to the quantity of impressions of stems, &c. of plants which we observed in the strata of the Lower New Red Sandstone. Specimens of these may be obtained in the Quarry Hill and Coleman’s Hull. LOWER NEW RED, STAFFORDSHIRE. 5 from these hills of yellow sandstones, to the edge of the great Dudley coal-field, whether from the Windmills and Two Gates, or from Hodge Hill, we find the following suc- cession : Ist. Beds of incoherent soft yellow sandstone, with calcareous courses and thin seams and fragments of coal. 9nd. Argillaceous strata, generally red, and of considerable thickness. 3rd. Sandstone, alternating with a peculiar trap-tuf. This rock sometimes assumes spheroidal forms, and will be further described in the chapter on Dudley. It contains quartz pebbles, and fragments of coal plants, is often highly ferruginous, and passes down into strata containing small concretions of ironstone. Ath. Calcareous shale with seams of coal, which have been, and are still worked. (See Pl. 37. fig. 6.) It appears, therefore, that between Hagley and Hales Owen, there are all the proofs of a Lower New Red Sandstone, distinctly underlying the masses described in the pre- vious pages, and passing down into carboniferous strata so gradually, that it is difficult to draw the line of separation, or define it with any accuracy upon a map. As this Lower New Red approaches the Clent Hills, it is inclined to the south, and is there surmounted by the calcareous conglomerate or central and upper strata of the New Red System. At whatever point we fix the limit between the overlying sandstones and the coal measures, it must be borne in mind, that the only carboniferous strata into which these beds graduate in this immediate neighbourhood, constitute the poor and slightly productive end of the Dudley field, and that speculation in search of coal seams by sinking to great depths beneath the Lower New Red in this tract, would be quite ruinous, since we know, that the mineral thins out to mere shreds in its course to the south. (See sections, Pl. 37. figs. 7 and 8. and further explanations of this point in the chapter upon the Dudley coal-field.) In following the margin of the great Staffordshire coal-field we invariably find, that wherever gravel and superficial detritus does not obscure the relations of the strata, a zone of red sandstone, sometimes of considerable thickness, is interposed between the coal and the calcareous conglomerate. At the Stand Hills, it is a hard, greyish, partially reddish, and slightly calcareous sandstone, with a few blotches of yellowish marl, and some veins of white carbonate of lime, passing upwards into a pebbly, deep red, soft sandstone. At the Straits between Himley and Turner’s Hill, it is a thick-bedded, deep red, soft sandstone, in parts slightly calcareous, full of irregular joints, and those numerous transverse strize or lines of false bedding so common in the New Red Sandstone, with occasional lumps of harder calcareous grit. At Sedgely, it is a hard, red, slightly calcareous sandstone, with spots of green, passing upwards into red argillaceous marl. These localities are all on the west side of the field, and the strata invariably dip to the west, or from the underlying coal measures’. On the eastern side of the coal-field, these sandstones are much more obscured by 1 See also the section from Wolverhampton to the banks of the Severn north of Bridgenorth, Pl. 29. fig. 13. 58 LOWER NEW RED, SHROPSHIRE. coarse gravel, but in several situations they are seen to be overlaid by a red calcareous conglomerate, which also dips away from the coal-field, or to the east. The great thick- ness of these lower sandstones has been recently proved by a spirited undertaking of the Earl of Dartmouth, at Christchurch near West Bromwich, to sink through them to the coal. These workings descended through a variety of red and spotted sandstones, blotchy deep red and variegated marls, and thick courses of red calcareous grit, concre- tions of impure limestone (cornstone), and ferruginous, deep red, hard, calcareous sand- stone, the fissures in the rock being sometimes coated with crystals of pink-coloured sulphate of barytes, and sulphuret of iron. At my last visit, the shafts, then at a depth of two hundred yards, were passing through a light red micaceous sandstone, in which blotches of ferruginous marl were mixed with grains of carbonaceous matter. Some of the layers of this rock were separated by lamin of black mica ; concretions of calcareous sandstone, as round as cannon balls, occurred at intervals, and altogether there was so much calcareous matter as to give the rock a very concretionary aspect. The reader will perceive, that these are the very same strata which overlie the coal in natural sections at other places; and hence there could be little difficulty in predicting, that coal measures would be found beneath them, particularly as it is well known, that the coal seams of the adjacent field of Dudley, do not deteriorate or thin out in the vicinity of these works, but are simply lost by faults. The existence of the upper beds of coal having first been ascertained by borings carried down to a depth of more than seven hundred feet below the surface; they (and the lower beds) have since been reached by sinkings, an account of which, with a full description of the strata passed through, will be given in the chapter on the Dudley coal-field. (P1.37. fig.1.) It is indeed impossible to mention this enterprise, without congratulating geologists on the effect which their writings are now producing on the minds of practical men ; since it was entirely owing to inferences deduced from geological phenomena, that this work was commenced, whilst its success was derided by many of the miners of the adjacent coal-field’. In the eastern parts of Shropshire between Enville and Bridgenorth the Lower Red Sandstone occupies low terraces and depressions beneath the calcareous conglomerate, and at Shatterford is conterminous with a thin band of coal measures. The uppermost strata are so very similar to those of the great mass of rock above the calcareous con- glomerate, that the description of the one, may almost serve for that of the other. Thus, for example, in the cliffs opposite Bridgenorth, and in the mass of rock on which the town itself is built, the beds possess nearly all the characters of the sandstones in the higher part of the system, being thick-bedded, soft, of a deep red colour, and traversed by innumerable lines of false bedding, which often meet in wedgelike forms; thus: 1 The Earl of Dartmouth commenced these works at the suggestion of his principal agent Mr. Dawson, a most intelligent gentleman, but not practically versed in mining affairs, who simply applied in this case the knowledge he had derived from geological writings. LOWER NEW RED, SHROPSHIRE. 59 a. Calcareous Conglomerate. b. Lamine of deposit in the Lower New Red Sandstone. I may here remark, that whether considered in its central or in its lower member, there is no system of rocks, which occasionally offers greater difficulties for determining its real Jamine of deposit than the New Red Sandstone. Besides the joints or fissures, the diagonal lines of false stratification are sometimes so prevalent, that it is only by tracing at wider intervals the true laminee of deposit, b. 6. (wood-cut), as marked by her- bage or moss, that we can correctly ascertain the real dip of the strata. As these ap- pearances sometimes reoccur, from top to ‘bottom of cliffs two and three hundred feet in height, and as the intervals between the true beds is often fifteen or twenty feet, it at first sight does not seem easy to assign an adequate cause for the accumulation of such a vast number of interjacent laminz, parallel to each other in separate wedges, yet divergent from the lines of true bedding. Such appearancs are to be found, to a cer- tain extent, in rocks of all ages, and however difficult it may be, to explain the precise method, by which water can have deposited the grains of sand in these positions, we have positive evidence of precisely similar phenomena, not only in young tertiary de- posits like the crag, but also in those accumulations of the modern era, which having been formed under the sea, have subsequently been raised up, and occupy low cliffs along certain parts of the coasts of our island!. To the south and north of Bridgenorth, the other strata of the Lower New Red, as exposed on both banks of the Severn, are similar in all respects to those described else- where, consisting of brownish, red, argillaceous and calcareous sandstones, flaglike, calcareous grits, with occasional underlying, slightly red and yellowish sandstones, not unlike certain coal grits. Before, however, we take leave of this tract, a little more detail is called for, respecting the relations of the Lower New Red to the south of Bridgenorth, where the formation has been generally confounded with the Old Red Sandstone; though it is clearly separated on many points from that system by a zone of coal measures. Such is distinctly seen at Chelmarsh, where a ridge consisting entirely of the Lower Red Sandstone, and associated beds of calcareous concretions, overlies in conformable apposition, and graduates downwards into strata containing 1 See description of a raised beach on the north coast of Devonshire, by Rev. Professor Sedgwick and Mr. Mur- chison, Geol. Proceedings. (Vol. ii. No. 48.) Mr. Lyell has given an ingenious explanation of the manner in which these transverse laminze may have been formed by water, in showing how similar inclined planes of sand are accumulated by wind. (See a full examination of this form of stratification, with numerous analogies drawn from the formation of the crag, in Lyell’s Principles of Geology, Fourth Edition, vol. iv. p. 91.) Mr. De la Beche also throws light on the origin of this false bedding. (See Theoretical Researches in Geology, p. 88.) . 60 LOWER NEW RED, SHROPSHIRE. seams of coal (Borle-brook). ‘The descending order on the western slope of Chelmarsh common is as follows: See Pl. 30. figs. 1. and 4. 1. Red sandstones passing into calcareous conglomerates, sometimes of concretionary structure, (summit of ridge from Chelmarsh to Higley). 2. Argillaceous marls and clay, with beds of whitish sandstone, occasionally with green grains. 3. First traces of coal measures, viz. dark and grey shale and light-coloured sandstone, with seams of coal, too poor to be worked. 4. Top coal of this district, twenty-two inches thick, the highest bed in use. 5. Calcareous concretions of grey and green colours, resembling certain varieties of the cornstone of the Old and New Red Systems; a band of this limestone is seen in the bed of the Borle- brook dipping under the top coal. 6. Lower coal, two feet six inches thick, with associated measures, lies at some depth beneath the limestone, but is not now in work. All these beds, from the lower coal to the overlying red and green sandstone with calcareous conglomerate, dip to the south east, about four inches in a yard’. This is indisputably one of the clearest natural sections in the range of the Lower New Red Sandstone, exposing a passage downwards to the coal measures. As these argillaceous beds with calcareous concretions, are thus proved to belong to the Lower New Red Sandstone, we thereby determine the age of other sandstones, which di- stinctly overlying them, occur on both banks of the Severn, at Higley, Stanley, and Alveley, and which most geologists, (myself included during my early examinations of this tract,) erroneously considered to belong to the Old Red Sandstone. Seeing the interstratification of so many beds of stiff red clay, with calcareous concretions per- fectly resembling the true cornstones of the Old Red, and also beds in which the sur- faces are occasionally covered with large plates of mica, it was difficult to believe that these rocks did not really belong to that System. By attention, however, to the relations of these sandstones to the surrounding strata, it becomes clear, that they belong to the New Red System; for besides the proofs of their superposition in this tract, they may be traced pursuing the same course and uniting with the sandstones of Hagley, the Clent Hills, Hales Owen, and the strata which surround and overlie the coal-fields of Coal Brook Dale and Shrewsbury. Grindstones. The red sandstone of Alveley, Higley, and Stanley, which contains calcareous concretions or cornstones (several masses of which are burnt for lime at Low and Shropshire farms) is a thick-bedded sandstone, without mica, the lamination fre- quently marked by purple stripes, with here and there, half-formed, small concretions of green and red marl. The coarser or gritty beds are very largely quarried for grind- stones, which are used at Birmingham in the manufacture of gun-barrels. The grind- 1 The Rev. T. England first made known this section, and showed the existence of concretionary cornstones in these coal measures. Geol. Proceedings, vol. ii. p. 20. LOWER NEW RED, SHROPSHIRE. 61 stones are not unusually three and a half feet thick, by ten or twelve in diameter’. These grits are frequently calcareous, and are composed chiefly of grains of deep red quartzose sand with white specks of decomposed felspar. Although, therefore, they do not much resemble the ordinary strata of the New Red Sandstone, they are unlike any beds in the Old Red System. And though it may be difficult, nay, in some cases impracticable, to distinguish the calcareous concretions of the one system from the cornstones and limestones of the other, we have a safe guide in the order of superpo- sition ; and the absence of the fishes and organic remains of the Old Red Sandstone, is negative evidence of some use in assisting the inquirer. In subsequent remarks upon the carboniferous deposits of these tracts, it will be explained, how the coal measures which appear in patches in the bed and banks of the Severn, have been brought to light from beneath this cover of the Lower New Red Sandstone. This member of the system is further developed on both banks of the Severn, north of Bridgenorth, or between that town and Madeley, leaving no doubt of its age, since it is seen overlying and dipping away from athin zone of coal at Tasley and Coughley ; and where some of the harder courses also contain calcareous sandstones. (Pl. 29. figs. 11, 12 and 13.) A most instructive transverse section can also be made by passing from the high terrace of Apley to the lower ridges, in which are situated the park and house of Mr. Whitmore. The change ob- served in passing from the fine sandy and loamy soil of the upper and middle portion, to the cold argillaceous surface of the lower division of the system, is quite as marked, as the contrast between the agricultural surface of the New and Old Red Sandstones, where those systems are brought together in Gloucestershire and parts of Worcestershire. (See Map.) So complete is the resem- blance between this lower member of the New Red, and the Old Red Sandstone itself, that I confess it was only the clear order of superposition which convinced me, that this zone of sandstone and clay really formed part of the younger system. Near Apley Park lodge, quarries have been opened in this rock to the depth of thirty feet, exposing a hard, greenish and deep red sandstone, in parts calcareous, in others slightly concretionary and conglomerated, the whole subordinate to stiff, red, argillaceous marl or shale. Here, as at Cantern Bank near Tasley, the beds lie conformably upon the coal strata, a band of which appears below in the bed of the Severn, while the superior face of the red rock dips beneath the overlying conglomerate of Apley Terrace. As Mr. J. Prestwich, to whose labours in this coal-field I shall have occasion to allude hereafter, has discovered plants in these Lower Red Sandstones ; the analogy to the strata of similar age near Hales Owen, Hagley, Shrewsbury, and other places, is complete. On following this rock to Coal Port Bank, we there see it exhibited in deep vertical sections. Thick- and thin-bedded, red, argillaceous sandstones; yellowish and greenish grits, occasionally calcareous, with wayboards of argillaceous marl, constitute the upper cliff, dipping to the east 10° under an argillaceous cover, and resting upon thick-bedded red sandstone, having a slight tendency ! The stone was also formerly much extracted for the furnace hearths of blast-houses, but experience has taught the iron masters, that many other sandstones are equally serviceable for that purpose. The coarser beds contain small fragments and concretions of marl. They are also used as building-stones. H 62 LOWER NEW RED, SHROPSHIRE. to conglomerate structure’. The other varieties of this rock contain rounded grains of quartz, and white specks, probably of decomposed felspar, with a little iron pyrites, in a calcareous paste, together with bands of coarse-grained pebbly grit and specks of chlorite, in a cement of white cry~ stallized carbonate of lime. Some of the calcareous grits enclose concretions of green and red marl, thus resembling the impure cornstones of the Old Red Sandstone. Between Coal Port and Made- ley this sandstone is affected by powerful faults, to the chief of which I shall advert in a sub- sequent chapter; it being enough for my present purpose to state that along the boundary of this field, as in Staffordshire, great dislocations equally affect the carboniferous strata and the Lower New Red Sandstone?. A transverse section from Sturchley to Shifnal, across Nedge Hill, like those previously cited, exposes sandstones and flaggy grits both green and red, and thin courses of slightly calcareous conglomerates and flagstones, associated with much argillaceous marl; the whole passing beneath the younger group of Shifnal, &c. The country around Shifnal, Sheriff Hales, and Crackley Bank, is covered with the quartz pebbles of the disintegrated conglomerate, beneath which a dark-coloured, finely laminated, soft, sandstone is seen at intervals; but these beds, as well as all those situated midway between Bridgenorth and Wolverhampton, and occupying points intermediate between the coal-fields of Staffordshire and Coal Brock Dale, belong rather to the overlying or great central mass of sandstone. At Lilleshall, the same instructive section, as that from Nedge Hill to Shifnal, is repeated with still greater clearness and fuller development (Pl. 29. fig. 15.) In the slopes of the hills below the terrace on which Lilleshall House is built, are stiff, argillaceous beds which produce a cold and unmanageable soil. Other sandy beds, on the contrary, are quite incoherent and very largely micaceous, a rare feature in the supracarbonaceous strata. At Lilleshall Abbey, the lowest strata apparent on the surface arethick-bedded, light brownish sandstones. The junction of these with the underlying coal has never yet been ascertained, but there can exist no doubt of these being the true beds of passage into the carboniferous system. Portions of this sandstone are seen at one or two points along the northern flank of the Ketley portion of this coal-field, and they follow the outline of the promontories of the trap and Silurian rocks near Wellington, but are for the most part in an incoherent and decomposed state, and the district is also much obscured by gravel. The lower red sandstone reappears at Wroxeter, Preston Boats®, Shrewsbury, and at other places upon the banks of the Severn. (See Map.) It dips away in slightly inclined masses from various small patches of coal at Pitchford and Uffington ; also near Longnor, where the coal-bearing strata of Le Botwood pass gently beneath the red strata of Condover and Stapleton. In that district, 1 There is a tradition that coal was worked immediately beneath this rock upon the south, and it is in every way probable that such was the case, seeing that the strata dip away from the coal-field of Brosely, on the opposite bank of the Severn. 2 These are all elaborately described by Mr. J. Prestwich, in whose memoir, preparing for publication in the Geological Transactions, will be found valuable details of the dislocations of the carboniferous and asso- ciated strata in this vicinity. 3 At Preston Boats the upper part of the old quarries exposes thin-bedded, hard, slightly calcareous beds, with small concretions of dark green impure limestone, closely resembling certain cornstones of the Old Red Sand- stone. In the lower part of the quarry the beds become thicker, and consist of sandstones of deep red colour, with a few blotches of marl. It is from beds of this age, that the Abbey, Castle and many ancient buildings of Shrewsbury have been constructed. ‘Though I have looked in vain for any traces of organic remains in these calcareous beds, we should never despair of such a discovery, when we recollect for how long a period the ex- istence of organic remains was unknown in beds of similar structure in the Old Red Sandstone. (See obser- vations on recently discovered plants and other remains in the New Red Sandstone of Worcestershire, p. 64 note.) LOWER NEW RED, SHROPSHIRE. 63 these red sandstones enter deeply into the recesses of the bays or denudations which have been formed at the north-eastern extremities of the Cambrian rocks, in many situations resting directly upon their vertical or highly inclined strata; while in others, as in various hollows near Cound and Pitchford, they are separated from the old rocks by thin patches and broken zones of coal. In all such positions, even at the north-western end of the Lawley and Caradoc ridge, these sand- stones, where not obscured by coarse drifted gravel, are soft, thick-bedded building-stones, usually lying in slightly inclined strata. In a quarry at Condover about thirty feet of these beds, dipping very slightly to the north-north-east, are arranged in the following descending order : 1. Gravel; 2. Thin-bedded sandstone; 3. Red, argillaceous marl; 4. Sandstone; 5. Argillaceous marl as above; 6. Sandstone; 7. Marls as above; 8. Thick-bedded sandstone. There are distinct evidences of the existence of the inferior beds of this formation, at various points west of the Wellbatch Collieries, near Shrewsbury, particularly on the left bank of the Meole Brook, where several pits and trial shafts, sunk by Mr. Hughes, have passed through,—Ist, Purple, red and green sandstones, marked by blotches of marl; 2ndly, Greenish and bluish shale; 3rdly, Whitish sandstone with green grains; 4thly, Coal-bearing measures. Of the last-mentioned rocks we shall have occasion to speak in a subsequent chapter, it being now sufficient to attend to the fact, that frequent impressions and fragments of coal plants have been discovered in these overlying red and green beds, which here form the cover of the coal-bearing strata. Most of these plants, like those of the Hales Owen and Hagley tract, are in an imperfect condition; but Professor ieviatey. had no hesitation in considering them as belonging to the carboniferous epoch. There are but few other spots around the southern edge of the Pontesbury or Shrewsbury coal tract, where the Lower New Red Sandstone is visible, owing to a great mass of superficial detritus; but the rock is laid open at Fairley, where it is a dark red, soft, thin-bedded sandstone, made up of black and white grains in a red paste, with a few harder concretions and some blotches of red marl. The same rock is also partially quarried at Newton near Boycot, where it is harder, more siliceous, and intractable, and it is again seen in the bed of the brook at Stretton, dipping to the north-east and north, &c., or away from the adjacent coal-field. In the escarpment at Cardeston, the same red sandstone underlies the dolomitic conglomerate, and dips away from the adjoining coal measures. In some of the quarries, this stone is of a light brown colour and consists of fine grains of quartz, much rounded, the matrix composed of earthy matter being freckled with dark stains, probably caused by the decomposition of small nests of iron pyrites. Following this escarpment to Pecknall, west of Alberbury, this sandstone is seen to rise from beneath the calcareous conglomerate, and to form a separate ridge between that rock and the coal measures of Coed Way. It is here a thick-bedded, deep red sandstone, with- out mica, speckled with whitish grains of decomposed felspar'. Like the lower beds in other places, it is also based upon argillaceous bands which decompose to a stiff, red clay, forming the immediate lip of the coal-field, and passing down into those beds of variegated shale which imme- diately overlie the coal. It may here be mentioned, that the transverse section at Alberbury and Pecknall proves, that the dolomitic conglomerate, the red sandstone, and the coal beneath it, are all arranged in conformable order of superposition, dipping to the east and east- 1 The sandstone of Pecknall is quarried to the depth of thirty feet and is an excellent building-stone brought into use by Sir B. Leighton, Bart., of Loton Park. H 2 64 SUMMARY OF THE NEW RED SYSTEM. north-east and resting upon the inclined edges of the Silurian system of rocks. (See Pl. 29. fig. 9.) The western extremity of Shropshire, affords still clearer proof of the Lower New Red Sandstone being directly superposed to the coal measures; for in the new pits at the Drillt, to the east of Oswestry, red sandstone, marl, and shale, have been penetrated to a depth of upwards of one hundred yards, before the first traces of coal measures were perceived ; when, after passing through several layers of impure carbonaceous matter, the usual coal seams of the Oswestry field were reached, and are now largely worked. (Pl. 30. fig. 13.) This case is precisely analogous to that of Lord Dartmouth’s colliery near Birmingham, and will be enlarged upon in the eleventh chapter. We have now gone through the New Red System, in as much detail as appeared requisite to point out its prominent features in this region; and I have attempted to separate the mass into divisions, which may stand the test of comparison with the sub-groups established in other parts of England, and with those sanctioned by foreign geologists. Closer comparisons appear impracticable, particularly as they must in the present state of our knowledge be chiefly founded upon mineral distinctions : for although one saurian animal and a few vegetable remains have been found in the sandstone of Warwick, and certain fishes have been detected in Ireland; the whole system in the central counties of England (with the exception of the shelly marls of Manchester, representing the Magnesian Limestone,) is poor in organic fossils. Certain sandstones, however, in Worcestershire are to be exempted from this obser- vation ; for, even while these pages are going through the press, both animal and ve- getable remains have been discovered in them, and will be described in the Appendix". 1 Being anxious to announce the discovery of any organic remains in the upper or central members of the New Red System, many parts of which I had not examined in detail, I recently requested my friend Mr. H. E. Strick- land to visit the quarries of Burg Hill near Eldersfield, the marly sandstones of which I have referred to the Keuper formation. (pp. 29 and 30.) Having done so, he has succeeded, after a minute search, in discovering “two indisputable fragments of bone, and some small oval bivalves, too indistinct to determine their genus.” One of the bones proves to be an Ichthyodorulite. Mr. Strickland’s section of the Burg Hill quarry is : ib, Feet. LGR ed evra re sent Ses aoe Bae mental, Se: subeips chet tee eieees « 4 Dip. S.W. 10°. 2G reenisiuereyal larly eyetes eye Sons Be ee, he eae ena 8 3. Thinly laminated Marl with white Sandstone .............-.. “ 4.U.Sottewhite Sandstone ta. : 8 Sion ar SPE aly Be Bene oo eee 6 ob eGreenish eucy larly sandstones) wenty rue ue eae eileen rm on ate gree 8 27 «These beds,” Mr. S. observes, ‘ thin out and vary in different parts of the quarry, the sandstone often pre- senting ripple marks on its surface. The marl No. 3. has been much cracked at the time of its deposition, and the crevices are filled with white sandstone in the same manner as those of septaria are with calcareous spar. From the tendency of the marl to split into spheroidal fragments, the curved fissures thus produced, when filled with the white sandstone, have very much the appearance of bivalve shells. Sometimes the marl is more broken SUMMARY OF THE NEW RED SYSTEM. 65 We may now conclude by simply recapitulating, that the previous details have shown the existence of— Ist, Saliferous and gypseous marls, with beds of sandstone, constituting together the equivalent of the ‘‘ Keuper”’ formation of the Continent. 2nd, Sandstones and quartzose conglomerates, representing the ‘‘ Bunter Sandstein”’ of the Germans, and ‘‘ Grés Bigarré” of the French. 3rd, Calcareous conglomerate, the position and structure of which proves it to be of the same age as the dolomitic conglomerate of the South-west, and of the Mag- nesian Limestone of the North-east of England, and that, however differing in mineral characters, it is therefore, as shown by Professor Sedgwick, the repre- sentative of the rocks known in Germany under the names of Zechstein, Rauch- wacke, &c. The trappean conglomerates on the flanks of the Malvern and Abberley Hills, are of about the age of this deposit, being clearly of younger age than the sandstones which form the true base of the system’. 4th, That the Lower New Red Sandstone overlying the coal-fields of Staffordshire and Shropshire, though differing considerably in lithological structure, is the equi- valent of those sandstones of the North-east of England, which occupy the same place as the ‘‘ Rothe-todte-liegende”’ and probably the lower beds of the Grés des Vosges*. The country described being intermediate between the south-western districts of England, where the dolomitic conglomerate rests unconformably upon the coal measures, and those northern districts where the series is fully developed, it is interesting to observe the points whence the expansion com- mences, and to mark the gradual increase of the lower deposits of the system, up and consists of detached angular fragments imbedded in the sandstone. The latter is commonly of very fine texture, but some specimens of coarse grit may be found, the pebbles of which (chiefly quartz) are one fourth of an inch in diameter.” Letter tomyself, March 11, 1837. In a subsequent letter, March 22, Mr. Strickland further announces that Mr, Amphlett, of Dunclent near Kidderminster, had discovered fossil vegetables in a stratum of ‘“‘dove-coloured”’ sandstone, which separates the great mass of red sandstone from the overlying marls. This band of whitish sandstone, very similar to that of Burg Hill, extends along the district of Doverdale. The plants, consisting of various genera, were chiefly found at Elmley Lovett, and at Hadley near Ombersley, and are now deposited in the museum of the Natural History Society of Worcester. I have requested that the specimens may be sent up to Professor Lindley to be described and figured in the Fossil Flora, and conceiving this discovery to be of great importance I shall visit the localities and announce the result in the Appendix.” March 23, 1837. 1 An expression has inadvertently crept into a previous sheet, p. 30, which I hasten to explain. It is there stated, that the conglomerates in question may represent the formations 2, 3, or 4, of this System. The conglo- merates here alluded to never can represent the No. 4, or Lower New Red Sandstone, but they are occasionally underlaid by a thin zone of sandstone, which possibly may be considered the feeble representative of that for- mation. 2 See Professor Sedgwick’s Memoirs, Geological Transactions, vol. iii. and iv. Consult also “ Systeme des Vosges,” of M. Elie de Beaumont, (Mémoires pour servir 4 une Description géologique de la France, vol. i.) ; the valuable Map of the Rhine, and “‘ Geognostische Umrisse der Rheinlinder,”’ by Oeynhausen, Dechen, and La Roche; and the work of M. Voltz before cited. 66 SUMMARY OF THE NEW RED SYSTEM. until they attain in these central tracts an importance as great, perhaps, as that of the same deposits, in Yorkshire, Durham, and Cumberland’. Among the peculiarities of the Lower New Red Sandstone of this region, one of the most remarkable is the prevalent diffusion of calcareous matter, and the existence of bands of concretionary limestone, some of which pass down into the coal measures ; in which respects the formation differs essentially both from its type in the North of England, and from its foreign synonyms. A practical acquaintance with the lower member of this system, is, it must be allowed, of vast national importance; for, as these sandstones are now proved to graduate into the coal measures, we need not despair of eventually finding some of the most valuable coal seams of the central counties extending beneath them. Such results would indeed be only a repetition of the successful enterprize by which, in sinking through deposits of the same age, the south-eastern part of the county of Dur- ham, in spite of the prejudices and predictions of the old school of miners, has now been rendered a great productive coal tract. If such be their practical value, these inquiries may also lead geologists to modify their previous theoretical views, respecting the relations of the coal measures to the overlying rocks, founded on what must now be considered local phenomena, observed chiefly in the Bristol district and south-western parts of England; where because the New Red Sandstone reposes wnconformably upon the carboniferous strata, the belief became prevalent, that this arrangement was indicative of a general rupture, subsequent to the accumulation of the coal measures, and anterior to the deposition of the mag- nesian limestone and conglomerate. That such, however, has not been generally the case, has been established with regard to the North of England, by the writings of Professor Sedgwick ; and the preceding facts teach us the same lesson in respect to the central counties: for it is clearly demonstrated, that beds of the age of the dolomitic conglomerate are there separated from those of the carboniferous system, by an un- broken succession of intermediate strata of vast thickness, of which there are few or no traces in the south-western parts of the island. Notwithstanding, however, the distinctions which have been drawn between the dif- ferent members of the New Red System in the central counties, a question it is feared might still arise among foreign readers, concerning the true equivalent of the Rothe-todte- liegende: for as most Continental geologists conceive that formation to be essentially connected with porphyritic and other rocks of igneous origin, they can scarcely peruse the description of the trappean conglomerates, p. 51 et seq., without supposing that those 1 These subdivisions of the New Red System of this region are not always easily recognised, owing to the prevalent obscuration and small elevation of the strata; and there is great difficulty in marking with precision their separate courses with accuracy. Two subdivisions only are therefore attempted upon the annexed map, viz. Ist, Marls, Sandstone, &c.; 2nd, Lower Red Sandstone including the overlying calcareous conglomerate and the inferior courses of concretionary limestone. SUMMARY OF THE NEW RED SYSTEM. 67 masses. may represent the German deposit. If, however, we are to understand the foreign synonym, to express a series of strata, elaborated in such a manner, as in some cases completely to connect the carboniferous and overlying system; then it is clear we must consider the Lower New Red Sandstone to be its true and full equivalent, even should it not contain a single pebble of trap. That it contains few or no fragments of trap in the North of England, has already been proved by Professor Sedgwick, and. the same fact is now established in the central counties ; whilst on the other hand the great trappean conglomerates have been shown to overlie this equivalent of the Rothe-todte- liegende, and to be on the same parallel with the dolomitic conglomerate. Referring to former opinions on this point Professor Sedgwick has well observed, ‘‘ In comparing the Bristol and Exeter conglomerates with the Rothe-todte-liegende, our geologists made use of the best evidence with which they were acquainted. But the New Red Sand- stone group is now better understood ; and in future comparisons with Continental de- posits of the same age, we should use as our types those sections which are most com- plete, instead of the Bristol or Exeter overlying groups, in which more than one half of the series is absolutely wanting.’”’ Geol. Trans., vol. iv. p. 400.’ The trappean ridges of Malvern, Abberley and Clent, will be described in the sequel ; but in the mean time it may be observed, that as the red conglomerates on their flanks contain angular and rounded fragments of the trap composing those hills, the rocks from which such debris was derived, must have been in existence before the conglome- rate was formed. Now, the rupture between the New Red Sandstone and the carboni- ferous deposits, as marked by the dislocations along the line of the Abberley Hills, would certainly lead us to suppose, that the eruptions which gave rise to these hills took place, either during the accumulation of the upper coal-measures, or of the Lower New Red Sandstone ; for, without anticipating explanations which are to follow in the en- suing chapter, it may be asserted, that nothing is more consistent with modern and ancient analogies, than that such volcanic eruptions should have been mere local phe- nomena, which in the tracts where they prevailed (Devon, Abberley, Clent, &c.) may have occupied the place of the Lower New Red Sandstone, by interfering with its de- position, while in the tracts not visited by these outbursts, the formation would naturally be fully developed, and would there exhibit the unbroken connexion between the New Red and Carboniferous Systems which has been detailed in the previous pages. ' I may here state, that after a recent examination of Devonshire and Somersetshire, by Professor Sedgwick and myself, we were unable to separate the lower part of the New Red Sandstone of that country, into two for- mations, like those of the northern and central counties ; and I am requested by my friend to say that he with- draws the qualifying expression (respecting the Exeter conglomerates) used in the Postscript to the memoir cited, and adheres to the opinion above quoted. (March 1837.) See Geol. Trans. iv. p. 403. CHAPTER V. TRAP ROCKS. Trap Rocks compared with Volcanic Products, and shown to be of Igneous origin. Distinctions between contemporaneous and intrusive Trap Rocks. ) HUITHERTO we have exclusively considered the nature of sedimentary deposits, but our account of them can no longer be advantageously continued, without occasionally describing rocks of very dissimilar characters, which have been abundantly intruded amid the strata. Already indeed the fragments of some of these rocks have been alluded to as forming part of certain conglomerates in the New Red System. These are the basalts, greenstones, porphyries, and syenites, which constitute a portion of the Trap Rocks of geologists. As my readers who have not studied geology will find in the sequel, that many important inferences in the theory and practice of the science, depend on the right understanding of the phenomena connected with these rocks, I deem it advisable in this introductory chapter, to explain their analogies with the products of existing volcanoes, and to point out how they have been proved to be of igneous origin. A slight acquaintance with volcanic phenomena teaches us, that they are the results of some general and deeply seated cause, which occasions eruptions of gaseous and earthy matters, or of lava, at irregular intervals, both under the atmo- sphere and beneath the ocean. Hence volcanic products are naturally divisible into two great classes ; sub-aerial, and sub-aqueous. ‘The first, being in many respects open to our investigation, is to a considerable extent understood. The second, for the most part hidden from examination, is necessarily but little known, though recent obser- vations have thrown some light upon it. It is to the last-mentioned of these classes, or submarine volcanos, that perhaps all our British trap rocks are referable. I will first very briefly point out the resemblance in mineral characters, between these rocks and modern volcanic productions, and secondly will endeavour to show, that the two classes are intimately connected with each other, both by association and physical phenomena. 1. Mineral character, &c. The most common ingredient in modern and ancient lavas, as well asin trap and granitic rocks, is felspar. This mineral assumes a consider- able variety of forms, which differ so greatly from each other, that a novice finds it dif- ficult to recognise in them the same substance. In an earthy, vitreous, or compact state, COMPOSITION AND PHYSICAL PHENOMENA OF TRAP ROCKS. 69 it forms the basis of all lavas, and of the greater number of trap rocks. Associated with augite, and generally in a vitreous form, it constitutes some of the well-known modern volcanic basalts, in which the greater or less preponderance of the latter mineral confers the more or less black, dense, and ferruginous character which they so often assume. Mixed with hornblende it forms a large class of ancient rocks, also called basalt when the minerals are intimately blended, or greenstone when each is distinguishable. In another condition, felspar, in a glassy but loosely aggregated state, composes a rock of a rough, porous, and earthy aspect, called trachyte, which is found among both modern and ancient lavas, and formations of still greater antiquity. In a compact state, the same mineral is the base of many of the porphyries ; and in a more or less crystalline form, associated with quartz, mica, and other minerals, it composes the great class of granitic rocks. As felspar is not found in any of the aqueous sedimentary deposits, except in a decomposed or regenerated state, it may therefore be considered the most characteristic ingredient of all igneous rocks. There are, however, many other simple minerals which combine to form these rocks ; but it is foreign to my present object to enter into further details, it being sufficient to state, that from the above-mentioned prevalent types of rocks, formed by heat, there are endless gradations into others, on many of which I shall treat in the following chapters. 2. Association and physical phenomena.—In taking a general view of the association and physical phenomena of igneous rocks, let us first take a rapid glance at the method by which the products of extinct volcanos' have been identified in their nature, with those of volcanos in activity. Ninety years have nearly elapsed since two French academicians, collecting plants . among the hills of central France, were astonished by discovering numerous cavities, resembling the craters of volcanos. From the lips of these cavities, currents of lava, as fresh in aspect as if they had flowed yesterday, were traceable into the neighbouring valleys, following their sinuosities, barring up their ancient water-channels, and moulding themselves into the inequalities of the actual surface ; and to complete the analogy with active volcanos, most of the mineral substances composing these lava currents were found to be similar to those of Vesuvius and Etna. When M. Guettard, one of the naturalists, first announced these discoveries, so unwilling were men of science to be- lieve in phenomena, of which neither history nor tradition had preserved a record, that scepticism long prevailed. The graphic and attractive descriptions of Montlosier’, the mineralogical knowledge of Dolomieu, supported by the precise geographical delineations 1 T might refer to a host of writers, both abroad and at home, including the early Italian writers, who have proved trap rocks to be of volcanic origin, and in the following pages some of these will be adverted to. The elementary works of Daubeny and Scrope must be consulted by those English readers who wish to comprehend the chemical and mechanical phenomena of modern volcanos. ® Hssai sur les Volcans d’Auvergne, Clermont, 1802. I 70 EXTINCT VOLCANOS OF CENTRAL FRANCE AND OTHER COUNTRIES. of Desmarests’, were all barely adequate to establish truths, which are now universally recognised, and have been rendered familiar to the British public by the beautifully il- lustrated work of our countryman Poulett Scrope’. The Hifel® in Germany has since been shown to be a tract in most respects analogous to Auvergne, while in Iceland are combined nearly all the phenomena which can be required to convince us, not only of the similarity of modern and ancient volcanic eruptions, but also of the great extent to which such phenomena have prevailed within the historic era*. Besides these well- known European tracts, other quarters of the globe, particularly the continent of South America and its adjacent islands, abound in examples of the varied phenomena of vol- canic action. In Asia Minor the district called the Catececaumene, described by Strabo, and recently visited by Mr. Hamilton and Mr. Strickland, presents an exact analogy with the volcanic regions of central France and the Eifel, &. But Auvergne is not merely replete with analogies to modern volcanic regions ; it was further found to contain many rocks, which, though from their characters they must have been formed by igneous agency, are yet in many lithological features dissimilar from modern lavas, whilst they resemble many of the so-called trap rocks. Thus, for example, though many of the “‘ lava currents” in the valleys of Auvergne are undi- stinguishable from those of Etna and Vesuvius, other currents, equally traceable to lips of craters, are composed of prismatic basalt very similar to the basalts of the Giant’s Causeway or of the Hebrides ; and pitchstone, that ancient form of obsidian, a mineral product so abundant in some existing volcanos, has been added to the list of analogies’. The district further presents numberless examples of other masses, of nearly similar composition, trachytes, ancient basalts, clinkstone, &c., some of which are undistinguishable from our British trap rocks, arranged in great tabular masses at various altitudes on the mountain sides. ‘These, unlike the more modern currents, are not traceable to distinct vents of eruption, and are in fact but the remnants of once ex- tensive lava currents, which had flowed over the surface of this tract before the forma- tion even of the present river courses. By such evidences, therefore, the inquirer is 1 Carte Topographique et Minéralogique du Puy de Dome. Paris, 1823. 2 Scrope’s Geology of Central France. London, 1825. s See Hibbert’s History of the extinct Volcanos of the Basin of Neuwied, 1832. 4 See Travels in Iceland, by Sir G. Mackenzie, Bart., and Drs. Holland and Bright; also Lyell’s Principles of Geology, where the author gives a vivid portraiture of the magnitude of the modern Icelandic lava currents. 5 See Lyell and Murchison “ On the Excavation of Valleys in Central France, Edin. Phil. Mag., July, 1829, p-15. Obsidian occurs in vast quantities at the Isle of Ascension. It would appear that this substance is also very abundant in parts of Asia, where its presence had not previously been recognised, as between Anni and Kars, for example, at a great distance from the coast. Mr. W. I. Hamilton has recently passed through that region, and thus expresses himself concerning it: ‘I had always imagined, that the accounts of mountains and palaces of glass belonged only to such fables as the Arabian Nights. To day, however, I passed over the foot of a mountain of glass, and where the roads were paved with the same material. It was in fact Obsidian, or Volcanic glass, most perfect and uniform in its texture.” (Letter to his Father dated June 30, 1836.) SUBMARINE VOLCANOS. 71 enabled to carry backwards his researches in the same regions, through connecting links, from the existing phenomena, into volcanic products of high antiquity. Again, many of the ancient volcanic rocks in Auvergne afford distinct proofs of having been poured into lakes, for they are interstratified and commingled with the freshwater and terrestrial spoils which constitute the lacustrine limestones and sand- stones of that region; thus explaining the geological period during which they were erupted, whilst the lofty positions they occupy, on the opposite sides of deep valleys over which they once spread in continuous masses, by demonstrating the enormous amount of denudation to which they have been subsequently exposed, convey to the mind some measure of their venerable age. In these tracts the phenomena are probably all referrible, either to subaerial volcanic action, or to vents of eruption from which currents of lava have been poured out into contiguous lakes. ‘The latter phenomena are analogous in kind, to that greater class of subaqueous lavas which have been formed under the sea, the condition of the waters alone constituting the difference. Now, as the greater number of existing active vol- canos are near the coast, so currents of lava have been repeatedly propelled into the sea. The coasts of Naples and Sicily, the latter particularly, present many examples of such currents, which have flowed into the sea in broad sheets, and have been consolidated under pressure into hard columnar lava, very similar to the basalts of older date’. We are thus naturally led to enter on the consideration of such volcanos of sub- aqueous origin, as have been attested by the sudden rise of volcanic cones and islands from the bottom of the sea. The isleof Nyoe on the coast of Iceland, the island Sabrina off St. Michael in the Azores, an island in the Grecian Archipelago, and Graham Island near the coast of Sicily, are well-known historical examples. The last-men- tioned island, having been thrown up so recently as the year 1831, when naturalists were quite alive to the importance of the deductions to which its apparition might give rise, has received much attention, and the series of phenomena which accompanied its appearance and disappearance have been faithfully recorded. They may be concisely stated as having occurred in this order : Ist. The soundings of Capt. Smyth, R.N.*, had established that the sea was upwards of 600 feet deep at this spot, anterior to the eruption. 2ndly. Ships passing near the place a short time before the eruption, were affected by earthquakes. | 3rdly. Commencement of the eruption: the sea thrown up in waterspouts, accom- panied by columns of steam and vapour. 4thly. The formation of a small island, at first only twelve feet high, with a central Dr. Daubeny has clearly explained how, under the pressure of an ocean sufficiently deep to prevent the formation of steam, the heat being carried off more slowly, the lava would longer retain its fluidity, and would ultimately arrange itself in crystalline forms, more or less prismatic and regular. 2 Phil. Trans., 1832, p. 255. to 72 EARTHQUAKES, FISSURES, ETC. erater ejecting volcanic matter and vapour, the surrounding sea being rendered turbid with floating cinders and scoria, and encumbered with dead fish. Sthly. The gradual increase of the island to 200 feet in height, and eventually to a circumference of three miles. 6thly. Its rapid diminution to a circumference of about 700 yards, when last exa- mined by the French naturalists’, under the erosive action of the waves and currents, which its loose fragmentary materials could not withstand. 7thly. Its final disappearance in less than three months from the period of its emer- gence. 8thly. The spot being surveyed in 1833, a year after its disappearance, the whole submarine remains of this mass, which had been raised from 600 feet beneath to 200 feet above the sea level, was reduced to a dangerous reef about eleven feet under water, in the centre of which was a black volcanic rock (probably a remnant of the solid lava of eruption), surrounded by banks of black stones, scoriz, and sand. In these well-recorded facts, therefore, we perceive that the eruption and demolition of this island, the apex of a cone 800 feet in height, must have covered the bottom of the sea to a great extent with detritus of volcanic ashes, scoriz, and lava, destroying countless marine animals, and mixing up their remains with the previous materials of the bed of the sea to form subaqueous deposits. We shall hereafter advert to the value of such a modern analogy in explaining many geological phenomena, particularly in the bedded trap rocks of the Silurian System. This slight sketch of volcanic eruptions may suffice to explain, that they could not have occurred without producing great and striking changes in physical geography. Important, however, as the volcano must be considered as a great natural means of de- struction and renovation, the earthquake, its constant accompaniment, operates perhaps still more directly as an agent of change, by elevating some tracts and by depressing others, causing great rents and fissures in the strata, and giving rise to powerful varia- tions of tides and currents, by which solid materials are transported to distant places. The volcano and the earthquake are in truth dependent on the same cause, and are but the outward signs of internal heat. The one is the ‘‘ safety valve,” by which heated matter escapes at intervals from the interior, the other is the shock which lacerates the solid ribs of the earth when that heated matter and its vapours, are denied an access to the atmosphere. One important task, therefore, of the geologist is to read off the proofs of these eruptions and earthquakes amid the ancient monuments which sur- round him on the surface of the earth ; and by examining them he learns, that from the remotest time there have been volcanic eruptions, and that the framework of the planet has been repeatedly subjected to intermittent violence and fracture. He perceives that 1 See a most instructive account of these phenomena by M. Constant Prévost, Notes sur]Tle Julia, Mém. de la Soc, Géologique de France, vol. ii. p. 91. BRITISH TRAP ROCKS SHOWN TO BE VOLCANIC. 73 many of these great eruptions and dislocations are intimately associated with other phenomena not less indicative of change. Thus within modern times, for example, irregular-shaped and narrow wedges of volcanic matter have crossed through the beds of ashes, scoriz, and lava which envelope and form the sides of Vesuvius ; and in like manner, similar masses (the dykes of geologists) are inferred to have penetrated in ancient times the solid strata of sandstone and limestone ; the latter where they are in contact with the intrusive rock, being often changed into a crystalline or highly indurated state. He further perceives that veins filled with simple minerals, frequently radiate through the sedimentary rocks where they are contiguous to such centres of eruption ; and thus he supplies the chemical philosopher with data, which at some future day may materially aid in solving the difficult problem of the origin of metallic veins ; at least the geologist shows the extent to which such veins may have been originally de- pendent on volcanic action. In our country we have no traces of subaérial volcanos; no craters like those of Auvergne, with pumice and scoriz adherent to their sides, or streams of lava traceable to their mouths ; nor have we volcanic islands rising from the bed of the sea: our only present memento of the existence of volcanic action beneath us, consisting in very slight shocks of earthquakes. On the other hand, however, Great Britain is rich in rocks possessing many mineral characters in common with volcanic products, being com- posed like them principally of felspar, augite, hornblende, and other minerals, and connected with them by so many gradual shades and links, that nearly all naturalists are now agreed that such rocks are the result of heat and fire. These are the syenites, porphyries, greenstones, clinkstones, and basalts, which have been forced up as molten matter through the submarine accumulations now constituting our sedimentary deposits’. Hutton, Playfair, and Hall were the first British geologists who brought the prominent features of such phenomena under the test of observation and experiment ; and clearly proved that all trap dykes were of igneous origin, and had been intruded among pre- existing strata; for it was shown, that as these rocks must have been erupted under the pressure of an ocean, so ought they, instead of being light and porous, to be hard, compact, and heavy, as we now find them. Obvious as these views may now appear, they required much subsequent illustration and support, before they could obtain that general assent to which they were entitled ; but to use the language of a sound observer, ‘* Nature fortunately remains more stable than prejudice’, and few indeed are those 1 It was this very intermixture of rocks having an igneous aspect with others which had been clearly formed under the sea, which led to those disputes about aqueous and igneous origin that now appear so trivial; the advocates of the Neptunian theory contending that all trap rocks were precipitates formed under water, because when compared with lavas they were found to be more compact! Yet, as Mr. Lyell has well observed, “The terms of comparison were imperfect, for one set of rocks formed almost entirely under water was contrasted with another which had cooled under the open air.” (Principles of Geology, vol. iv. p. 353.) - * Bakewell, Travels in the Tarentaise, Alps Auvergne, vol. ii. p. 295. 74 BRITISH TRAP ROCKS SHOWN TO BE VOLCANIC. who now venture to dissent from the doctrines of the Scottish philosophers. No individual has more advanced this branch of the science than Macculloch: few mi- nutiz of chemical combination, lithological structure, or mechanical effect escaped him ; and to the accuracy as well as to the number of his observations, we are indebted for many of the most satisfactory proofs of the volcanic nature of the class of rocks under consideration. In short, he well remarks: ‘‘ It is a mere dispute about terms to refuse to the ancient eruptions of trap the name of submarine volcanos, for they are such in 1 93 every essential point, although they no longer eject fire and smoke’.” Following up this train of research, the same author further proved, that granite was but one term in the series of igneous products, tracing with scrupulous accuracy the passages from what was formerly called primitive granite, to granitoid syenite, and syenitic greenstone, and thence into greenstone, basalt, and lava’. Such is a mere outline of the grounds upon which geologists have arrived at the con- clusion, that trap rocks are of volcanic origin. In the course of this work, examples will be first adduced of phenomena illustrative of the relations of intrusive trap ; or of volcanic matter which has burst in irregular forms through sediment previously deposited ; and pursuing the inquiry in subsequent chapters, it will be shown, that the greatest fractures of these deposits have taken place on lines of volcanic eruption, or upon such as are parallel to them, usually accompanied by considerable changes in the condition of the strata thus penetrated. There is, however, another and a very ancient class of 1 System of Geology, vol.ii. page114. See also this author’s beautiful and instructive work on the Western Highlands, with plates. Classification of rocks, &c. 2 Having alluded to the school of Scottish geologists, I have much pleasure in recording my sense of the eminent services of Professor Jameson in classifying the trap rocks of his country. Imbued in early life with the tenets of Werner, his first views, like those of all the pupils of that master, were necessarily opposed to those here advocated; but we must not forget that the opposing arguments of this skilful mineralogist led to many of those discussions which have at length freed the subject of its obscurities; whilst it is most creditable to the candour and philosophic spirit of Professor Jameson, that being once conyinced of the igneous origin of trap, he joined issue with his former opponents, and has now become one of the most efficient expounders of that theory. . Dr. Ami Boué (whose indefatigable research has led him at this moment into the Servian and Turkish moun- tains,) will always occupy a place in the memory of British geologists, for having at an early period applied his powers to describe the mineral structure of Scotland, and to endeavour to class its trap rocks (Essai Géo- logique sur U Ecosse). Nor can we forget that Necker de Saussure was educated in the same school, and by a work of his youth (Voyage en Ecosse et aux Iles Hebrides) gave earnest of one day maturing into the author of the Regne Mineral, (Geneva, 1836). With these brief allusions to what may be termed the history of British trap rocks, I ought perhaps to advert no further to foreign writers who have enlightened us by their views, but my vivid recollection of the energy and talent displayed by the Prussian geologists Oeynhausen and Dechen in describing many of our insular igneous products, impels me to say that the comparisons drawn by them be- tween these and rocks of similar structure on the Continent are striking proofs of the value of such inter- national visits. (See Karsten’s Archiv; Inseln Skye, and other works). MM. Elie de Beaumont and Dufrénoy likewise having made themselves perfectly conversant with our rocks, have drawn excellent and illustrative parallels. q DISTINCTIONS BETWEEN VOLCANIC GRIT AND INTRUSIVE TRAP. 75 trap rocks, which has been little adverted to by writers, and upon which I shall’ en- deavour to throw some new light. These are the rocks named in the following chapters “Volcanic grit,” ‘‘ Bedded and contemporaneous trap,” and which I undertake to prove were formed at the bottom of the sea during the accumulation of the sedimentary matter with which they are associated, particularly in the lower strata of the Silurian System. At one place these appear as currents or sheets of pure volcanic materials, at another they envelope marine remains, pebbles, sand, and fragments of rocks. Some layers consist of finely levigated volcanic scoriz passing into sand; and all these varieties alternate so equally and repeatedly with beds composed exclusively of shelly and marine sediments, that no doubt can be entertained that the diversified masses so arranged in parallel strata, must have been formed during the same period of igneous action. In the remote era therefore of the Silurian System, the evidences of volcanic operations are similar to those which Mr. Lyell has noticed in the modern deposits of Sicily, where banks of existing species of marine shells, now at considerable heights above the sea, are so interlaced with volcanic matter, that no other deduction can be permitted, than that the whole of these masses were of contemporaneous submarine formation. ‘“‘ We are therefore,’ adds that Author, “‘ entitled to expect, that if we could obtain access to the existing bed of the ocean, and explore the igneous rocks poured out within the last 5000 years, beneath the pressure of a sea of immense depth, we should behold formations of modern date very similar to the most ancient trap rocks of our island’.”’ Tn pointing out an analogy to existing nature in the bedded trap of a very ancient geo- logical period, we also fix the chronology of one class of igneous rocks ;—for those of intrusive character so predominant in these islands, are rarely capable of such a limita- tion. We have often heard, indeed, of ‘“ coal measure trap,” and ‘‘ greywacke trap,” as if such rocks were formed during the carboniferous or greywacke periods, whilst in the great majority of examples nothing is further from the truth. For instance, it will pre- sently be shown, that basalt has penetrated and overflowed coal-fields, dislocating and fracturing the strata, and therefore we know it must have been erupted subsequently to their consolidation: but as the carbonaceous strata so affected are not covered imme- diately by any newer deposit, at what period were they so penetrated ? Examples, indeed, will be given, from which it may be fairly inferred, that the coal-bearing strata have been forced up through once overlying red sandstone, and therefore that some of the volcanic agents which disturbed these coal-fields were in action subsequently to the era of the New Red System. In the same manner trap will be shown to have pene- trated new red sandstone, and reasons will be given for legitimately concluding, that such eruption took place after the completion of the New Red System, and even pro- bably of the Lias. ' Principles of Geology, 4th edition, vol. iv. p. 254. 76 BEDDED TRAP IN CUMBERLAND AND WALES. But if analogous proofs of this nature be sought from other parts of the island, the great basaltic dyke which ranges from a focus of volcanic action near the sources of the Tees, to Robin Hood’s Bay on the coast of Yorkshire’, intersecting all the formations from the lowest coal-measures to the inferior oolite inclusive, affords the best example of the impossibility of inferring the age of trap, from that of the sedimentary rock with which it is found in intrusive contact. The observer whose researches did not extend beyond the coal-measures, might assign the date of irruption to that formation ; while another exa- mining the Yorkshire coast would prove that it was of an age posterior to the oolites. Lastly, as if tending to exclude all limitation, the North of Ireland tells us that basaltic and other trap rocks, even including syenite*, have been erupted through chalk, the very youngest of our secondary formations ! Where then, we may ask, can the geologist arrest his\ steps in deciding upon the age of many of these masses of eruptive trap? How can he venture to assert, that the very basalt which has flowed over the coal of the Clee Hills, or pierced the coal of Staffordshire, was not emitted after the accumu- lation of the most recent of our secondary rocks? or that some of these eruptions may not have accompanied those movements of elevation, by which even the youngest tertiary deposits of our island were raised from the bed of the ocean ? Whilst, therefore, it is always difficult, and often impracticable, to define the age of some of the intrusive trap rocks, the more gratifying is it to retrace in other masses of the same class formed anterior to the accumulation of the Old Red and Carboniferous Systems, the clearest proofs of intermittent and repeated volcanic emissions ; for, although they have been poured out in a period of high antiquity, we are still able to read off in them distinct analogies to Nature’s present operations. The types of the Silurian System and the associated volcanic rocks have remained so clear, that the geologist has in them a record never to be mistaken,—one which will enable him to descend from their horizon into those deeper-seated rocks, amid which Professor Sedg- wick has detected analogous relations ; showing that in Cumberland and Wales there are numberless bands of porphyry, interstratified with, and participating in all the flexures of the slates, the whole of which have been subsequently pierced through by other and intrusive masses of igneous origin. But although in these regions, the vol- canic operations have been upon a grander scale than in the Silurian country, there is not (I speak on the authority of my friend), that clear demarcation between the pro- ducts of fire and of water, to which I shall in subsequent chapters direct attention, the whole mass of rocks being generally crystalline and altered (metamorphic), and very rarely presenting any traces of organic remains. And hence these regions are ill fitted 1 See an excellent account of this basaltic dyke and the associated phenomena by Professor Sedgwick, Trans. Phil. Soc. Cambridge, vol. i. p. 139. ® Mr. Griffith discovered this phenomenon and announced it to the British Association at Dublin, 1835. Subsequently Professor Sedgwick and myself visited the locality in company with Mr. G. See Geol. Proc., Phil. Mag., vol. viii. N.S., p. 559. DATES OF ERUPTIONS. 77 for elementary study, as it requires long practice to decipher correctly such dark pages in the history of the earth. To the phenomena, however, illustrating the stratified trap rocks of the Silurian System, the reader will not be invited for some time, as he must previously accompany me in descending order through many overlying deposits, till we reach the older Silurian rocks, occupying the western part of Shropshire and adjacent parts of Montgomery- shire, as well as large portions of Radnorshire ; districts which, (as far as my knowledge goes) are unrivalled in the British Isles, for the number and clearness of the illustrations bearing on this interesting point of inquiry. Let not my reader imagine, it is here asserted, that contemporaneous and bedded trap rocks, similar in kind to those of the Silurian System, do not sometimes exist in overlying formations ; reasons, indeed, will hereafter be adduced which favour the belief, that even in a part of the region under consideration, rocks of this character have been elaborated during the carboniferous cera, though not in the same striking manner as in the Lower Silurian epoch. The “trap tufs”” of Hales Owen, hereafter to be described, must either belong to this class, or be considered as regenerated deposits, the trappean ingredients having been derived from preexisting and solidified masses of rock. This ambiguous point will be fully con- sidered in the chapter on the Dudley coal-field. But in other parts of the kingdom the secondary formations afford proofs of these phenomena. Thus, in Devonshire, Mr. De la Beche has recently observed the existence of trap, which from its relations, he con- ceives must have been ejected during the formation of the lower members of the New Red Sandstone of that district’. Again, in the North of England, Mr. Hutton has at- tempted to show, that the eruption of a large portion of the whin-sill or basalt of Nor- thumberland and Durham was coeval with the carboniferous epoch, whilst another portion of it has been demonstrated by Professor Sedgwick to be of comparatively recent date*. Such examples are quite in accordance with natural laws; and as our field of observation extends, there can be little doubt, that the phenomena of bedded and contemporaneous trap rocks will hereafter be recognised in many deposits of different ages. As this work professes to describe geological phenomena in descending order, or in other words from the more recent to the more ancient, it might be expected that this general view of their origin, would be immediately followed by a description of the trap 1 Geol. Proc., Phil. Mag., vol. vii. N.S. p. 518. * Hutton on the stratiform basalt associated with the carboniferous formation of the North of England, Trans. Nat. Hist. Soc. of Northumberland, &c., vol. ii. p. 187. Having examined a part only of the country described by Mr. Hutton, I cannot pretend to oppose my opinion to that of one who has so ably explored the whole of it; but as far as I saw them, the phenomena in the valley of the Tees (High Force, &c.) appeared to me to support the views which Professor Sedgwick had previously drawn from an examination of that portion of the tract in question. On this point, however, Professor Phillips justly observes, ‘It is not necessary to suppose that only one submarine flow of basalt occurred, any more than to confine it to one opening.” Geology of Yorkshire, vol. ii. p. 85. K fitete DATE OF ERUPTIONS IN THE ABBERLEY AND CLENT HILLS. rocks which in the map and sectional illustrations appear in immediate relation to strata already described (the New Red System). lam, however, acquainted with one example only in this region, where trap can be seen to have been intruded into the New Red Sand- stone; and this intrusion having taken place on a line of ancient volcanic eruption, the origin of which cannot be understood without a previous acquaintance with the history of the Silurian System, the account of this new red trap dyke is necessarily deferred to a subsequent chapter. In like manner, I postpone the consideration of those peculiar trap rocks, which rising to the surface in the Abberley and Clent Hills and adjacent tracts, frequently separate the New Red Sandstone from the coal-measures, for their relation cannot be comprehended until the carboniferous strata with which they are associated have been described. This class of trap rocks, though evidently of intrusive cha- racters, yet carries with it unequivocal proofs of the period of its emission, and is, therefore, a marked exception to the eruptive rocks previously alluded to, the age of which is not bounded by clear geological limits ; for, as already briefly hinted at, the syenites, porphyries, or other felspathic rocks of which these hills are composed, were manifestly erupted before the accumulation of the greater portion of the New Red Sandstone, since fragments of them occur abundantly in conglomerates near the lower part of that system. On the other hand, as some of the adjacent carboniferous strata are shattered and highly dislocated, ample proof is afforded, that these trap rocks must have been thrown up, either towards the close of the carboniferous era or during the earliest period of the New Red System; and thus we have aright to affirm that the epoch of their eruption is fixed’. After this digression explanatory of the rocks of igneous origin, we may again pro- ceed to consider the stratified deposits in their regular sequence, commencing with the upper surface of the carboniferous series, at which we had already arrived in descending order; simply premising, that after the explanation here given, the description of trap rocks, wherever they occur, will, in each succeeding chapter, follow the account of the sedimentary deposits with which they are associated. 1 The reader will better understand the object of this chapter after consulting the small coloured sections II. and III. which are placed upon the margin of the map. The opposite sketch is taken from the upper part of Hagley Park, the seat of Lord Lyttelton, placed on the north-western slope of the Clent Hills, one of the trappean ridges alluded to in the text; the Malvern Hills, which are also of the same class, appearing in the distance. The Abberley Hills, or northern prolonga- tion of the Malverns, are seen from the same spot, but can be included only in a panoramic drawing. ‘The low country or plain of Worcester is occupied by the New Red Sandstone described in the previous chapters. I am indebted to Mrs. T. Phillips for this beautiful drawing. ‘ yrez ery “UOT “WAL SMOMOM FO RTA VEY “STORIG NM ATT IN a * - om - . a : i ay é - SAG Fst + feet ee ° e a finert ere 4 a mic J a ae | hae? : ys nama Stee Se SSS Nhe 90 : SAN gg) cite ote ; Alp er TS q , Oe eee NN ey La SF oes Bee 5 . AS ON PBK, 2 Sa = MN AE ; ite, Wier ones eg ET LS acc r 7 on CHAPTER VI. CARBONIFEROUS SYSTEM. Introduction— Upper Coal Measures and Freshwater Limestone. Introduction. MY chief object in this and the next six chapters, is to convey a clear idea of the pro” minent relations of the carboniferous strata to the overlying and underlying systems, and to furnish means of comparing these rocks in the region under examination with those of similar age in other parts of Great Britain. Following up the inquiry com- menced towards the end of the fourth chapter, I would first direct attention to those tracts, where there are evidences of a passage downwards from the Lower New Red Sandstone into the carboniferous strata. It will afterwards be shown, that the under- lying formations of millstone grit and carboniferous or mountain limestone, are unpro- ductive of coal; and lastly it will appear, that the carboniferous limestone graduates downwards into the Old Red Sandstone with as much regularity as the Lower New Red Sandstone passes down into the upper coal measures. These general views are explained in this wood-cut. a. Lower New Red Sandstone, with calcareous concretions described in the last chapter. 6. Upper coal measures with freshwater limestone. e. Main coal. d. . Lower coal and ironstone. é. Millstone grit. jf. and g. Carboniferous limestone and shale. #. Conglomerate and sandstone, or upper formation of the Old Red System. The various coal-fields will be described in the following order. 1. Shrewsbury. The carboniferous strata around Shrewsbury will be shown to con- sist of a younger or upper zone, which immediately succeeding to the Lower New Red Sandstone, contains within it a limestone of freshwater or estuary origin, peculiar to the coal-fields of the central counties of England. re 80 CARBONIFEROUS SYSTEM.—INTRODUCTION. Coal Brook Dale. The account of this, the most productive of the Shropshire coal- fields, will naturally follow, to show, that the thin or upper coal measures of Shrews- bury, reappearing in this tract, are underlaid by lower and thicker carbonaceous masses, containing many beds of valuable coal. Descriptions of the other detached coal-fields of Shropshire will then be given in the following order. The Clee Hills ; The Forest of Wyre, or Bewdley, and Oswestry. Quitting the Salopian fields, and passing to the south, the small district of Newent, in Gloucestershire, will claim a brief notice; but the important coal basin of the Forest of Dean will not occupy attention further than by occasional references, since it has been adequately illustrated by Messrs. Buckland and Conybeare, aided by the local knowledge of Mr. Mushett’. South-Welsh Coal-field, (Glamorgan, Monmouth, Brecon and Caermarthen). No detailed account will be given of any part of this valuable and rich basin, which has been long under the examination of the Rev. W. Conybeare, for whose memoir every geologist is looking with impatience ; but the boundaries of this tract will be alluded to, their eastern, northern and western outlines having been accurately laid down on the map, to indicate the great disruptions along the margin of the basin, and to show the vast expansion of the carboniferous limestone between the South Welsh and Bristol coal-fields. We shall then proceed to the consideration of the Old Red Sandstone and Silurian rocks ; the description of the coal-fields of Pembroke and Dudley being deferred to future chapters, as the carboniferous strata in these tracts are so intimately connected with the older rocks, that the history of the one would be unintelligible without a pre- vious acquaintance with the other. In this manner, after a regular examination of the whole succession of rocks, the complicated tracts of Pembrokeshire and Dudley, in which so many different members of the series are intermixed, will be the more easily explained; clear comparisons being established between them, and unequivocal strata in other parts. Thus carrying down our observations in descending order, the reader will be first familiarized with the nature of those coal-fields, which, although they have hitherto met with little attention, are not only of geological, but also of national in- terest ; for as they are overlaid by the New Red Sandstone, so they may hereafter be worked from beneath that system in several of the central counties. But besides the regularly stratified deposits of shale, coal, sandstone, grit, and lime- stone, of which they are composed, some of these coal-fields are perforated by trap 1 The outlines of this remarkable coal basin, so symmetrically surrounded by zones of millstone grit, carbo- niferous limestone, and Old Red Sandstone, will be seen by reference to that part of the map which has been coloured from the original work of Mr. Maclauchlan, of the Ordnance Survey, now deposited in the collection of the Geological Society. Iam indebted to this gentleman for much valuable information concerning this and other adjacent tracts, and particularly in the delineation of the outline of a large portion of the South Welsh coal-field, with the topography and geological structure of which he is most intimately acquainted. UPPER COAL MEASURES OF SHREWSBURY. 81 recks, which, as before stated, will be described towards the end of each chapter to complete the geological survey of the tracts in which they are found. I have further endeavoured to explain the probable orzgin of the central coal-fields, by observations scattered through the sixth, seventh, and tenth chapters, and particu- larly at the conclusion of the eleventh chapter, in which we take leave of the carbo- niferous tracts of Shropshire. | 1. Upper Coal Measures and Freshwater Limestone. (0. of wood-cut, p. 67.) By inspecting the map it will be seen, that the ancient rocks which compose the Silurian and Cambrian Systems, ranging from Pembrokeshire on the south-west, termi- nate on the north-east in a succession of promontories, more or less parallel, and of unequal lengths, which form the southern, western, and eastern limits of the plain of Shrewsbury. These promontories are fringed by a narrow, broken, and devious zone of coal measures, extending from the Breidden Hills on the west, to the Wrekin on the east, the base line or lower edge of which, is determined by the headlands and bays of the ancient rocks. Sometimes, indeed, the carboniferous strata are so completely isolated by these protruding inferior masses, that they consist rather of a number of patches than of a continuous band. By this disposition, the coal measures repose un- conformably and successively, upon rocks of various ages, from the flanks of which they dip away ; and where not obscured by overlying drifted materials, they are seen to graduate upwards into the Lower New Red Sandstone, passing at slight angles of inclination beneath that formation. (PI. 29. Figs.3,4,5,7and9.) The surface of a large portion of the plain of Shrewsbury is represented in the annexed view, the various ridges in the distance being composed of Cambrian, Silurian and Trappean rocks. The low country consists of New Red Sandstone and coal measures, for the most part overspread by a great thickness of gravel and detritus. Let us first examine the portion of this tract which is productive of coal, and lies between the north-eastern termi- nation of the Breidden Hills and Shrewsbury. The principal outcrop of the coal is in a semicircular bay, of which Shrewsbury and Coedway are the eastern and western ex- tremities, and the intermediate places where it has been worked, are Nobold, Wellbatch, Aston, Pontesbury, Minsterly, Westbury, Woolaston and Braggington; at most of which places the strata have only a slight inclination towards a common centre. It has already been stated, that the lowest strata of the overlying red sandstone at certain points in this district are in contact with, and in some instances graduate into the coal measures. This passage is seen at Wellbatch, Asterley, and Coedway. In these situations the coal measures rest on one side against ridges of older rocks, and on the other, dip in perfect conformity beneath the Lower New Red Sandstone. (See Pl. 29. fig. 5.) From the arrangement of these beds, as seen near Nobold, where the New Red Sandstone dips to the north-west, conformably with the inclination of the coal beds, 82 UPPER COAL MEASURES OF SHREWSBURY. no geologist could doubt, that the red rock immediately overlies the carboniferous strata; and this conclusion has recently been established by sinkings, which having passed through variegated shale of the Lower New Red Sandstone containing impressions of plants, reached coal-bearing measures’. At Coedway, west of Alberbury, the opposite extremity of the trough, the coal strata dip to the north-east, again passing beneath red shale and sandstone, but the seams are of little value and have not been followed upon the dip. (Pl. 29. fig. 9.) In most other portions of this trough there is no pos- sibility of observing the precise relations of the coal measures to the overlying strata, owing to an enormous accumulation of coarse detritus which overspreads the country. The following account, therefore, of this tract is derived from observations made at points where the coal has been worked along the tortuous line above indicated, and also in the several bays and recesses of the older rocks to the south-east of Shrewsbury. (See Map and view.) Where most developed, this formation contains three seams of coal, which, in de- scending order, consist of half-yard, yard, and two-foot coals. The quality, thickness, and even the number of these beds vary in different places, but it may be stated as a general rule, that the lowest or two-foot coal is the best, the middle and upper seams being for the most part pyritous and of inferior quality, particularly the yard coal, usually termed “‘ Stinkers.” These coal beds are separated from each other by red, green, and black shale, and clod, some portions of which have a saponaceous feel, as if charged with magnesia, and thus they bear some resemblance to the variegated shale or marl of the overlying New Red System. The intervening argillaceous beds, containing occasionally a bed of sandstone, are of unequal thickness in distant parts of the trough, but at Pontesbury they amount to about fifty yards. Owing to the unequal thicknesses of the overlying strata, and also to numerous dislocations, the coal seams are neces- sarily reached at various levels, the depths of the shafts increasing with the distance from the natural outcrop of the coal. The deepest pits, or those furthest from the edge of the field, are about ninety-five yards, whilst the shallowest or those nearest to the hilly sides of the older rocks are not more than ten or twenty. Wherever the measures have been examined between Pontesbury and Westbury, the three beds of coal have been found; but to the westward of the latter place one of them appears to thin out. There is, however, a considerable space along which no trials have been made, and the old works at Woolaston have been so long abandoned, that no correct information is to be obtained respecting them. At Braggington and Coedway, the western termination of the field, there are only two beds of coal worth working, the ' The trials alluded to were made by Mr. Hughes of Wellbatch, and the fragments of plants in the varie- gated shale were recognised by Professor Lindley as being similar to those found in other coal-fields; but un- fortunately the specimens have been mislaid, and I am now unable to state their specific names. (See an ac- count of plants found in red shale or marl above the coal measures of this age at Ardwick, near Manchester, p- 88, note 1.) ‘ * sel ro ae SNe A si DI: Webster et —— Ud fo pres a apa ee or € BET al ; PR ar bella es we EH 6 pag ee RAR AES oe, , 4 wy NAV AAS E . ' : ; 3 a : ne f a PN x ca naan Che SERS Oto : ; = x a Ei ’ a hs é Cr <. w me wt ith POSS 3 2 : f “oh A 1a Feces *AADY par Ahh nee yen, “a ae arts: ohn, Feiner E a a 5 TE ce OO hg we “8 ar) I i ag AD ict yey TMD = Ne iciae The Corndon.. nie A = eet ENG UI Me SE oa BOE ry ES Ticaen ™Stiper Stones. _ : ;, HaeRh te RM BE ogg, le As re “nPontesfor a. Hall Pontesey Haughimond Hall. sate : The Long my »Pontestor Le Coal Bite . TPE e Wrekin . a: +a ae y Vell 2 Lt s . ap stan Brown Clee Sates, «lbsarakoss ( Ww atch Coal Pits ee ae? 2 — - Se pasted Z Zeal Castle and Towm of Shrewsbury Wenloc E Ba Ze . | Day bHaghelitye™ to the jeer = Mn — 7 + A ¢ A WY ID S$@OvuTe VIEW FROM NEAR SHREW IW G TOWARDS THE EAST AND SOUTH ; FRESHWATER LIMESTONE. 83 lowest of these, or the thin coal, being from about fifteen to eighteen inches thick. The works at both these places are abandoned, those at Coedway having been wrought during a period of twenty years. At Braggington a good deal of capital was recently expended, but the thinness of the beds, their dislocations and high inclination, (close to the edge of the trappean rocks of the Breidden Hills,) and their distance from any good market, led to their abandonment. It appears, however, that the works were conducted in an unscientific manner; for there can be no doubt, that these beds of coal, though thin, might, if well managed, prove of considerable use in this district in burn- ing the contiguous limestone of the dolomitic conglomerate. (Pl. 29. fig. 9.) The pre- sent success of the pits at Westbury is indeed a proof of how much may be done by spirit and assiduity. ‘* Freshwater Limestone.” The most remarkable feature in this coal-field, and one quite new to geologists when I announced the discovery, is a band of limestone, varying in thickness from three to eight feet, which lies between the seams of coal. The following shaft section of the strata at Pontesford shows its exact position, and explains the nature of the associated beds in a part of the coal-field where they are perhaps most developed. ft. in. a. Gravel and detritus, thickness variable. b. Various overlying strata of variegated shale, sandstone, clods, &c., with traces of lime and ironstone. These are the beds of transition or passage from the Lower New Red Sandstone. (See better detail of these beds at Wellbatch, | DELI) tered eee 90 ce. 1st or half-yard Coal, of good quality in some places near the outcrop, but generally more pyritous and sulphureous on the dip cS — SEmLeL fod a? 10% “© ‘eo: :6: Fe. -e8 .6) 00h 6) D0) ‘en a) eke eo ets ef 6 d. Poundstone and Crundall, i. e. variegated sandy shale, with traces of coal plants .. . e. Sandstone, in beds of from three to four feet; a good building-stone.......... jomivedssi(Stiltgsbalo rele . 8.6 so Pee Bee a Soce, ess HTS ey Oe Ce ie asl hice Cin prntye wintbishes Wale). TOs « sew a eee 6 oe se ees ee yw ot | [plover ACEASA(MUIXCUGSEME)) aceateoresatvare re «ce teciccdesettes-retes 010 Limestone of similar structure and containing the same organic remains as that OLE LTO ASSO aracden dea cSr had nce ladsucgdbsoSadhganaderinhoocoub Enocenpansrbahoot brands 1 F080 UCAS sncmacte tee aseatuiscieecsdaeeraenaann da ermccte dey ataes ced da acites cath weer nace nate 5 0 0 iBluctelodsvand noot-of coal with plantsmen. ++ secorsc.4s.tescnsseetoes sere eete teen aes 7 40) <0 GQ Oa lecnreasereraseatas cia tandets acnnaciesanaessnmreees sentence cebeu cay ciate errs meen een 10 ERO Round stoner cs cce- anes: causene seam ates een aca eee eaeet- ca eaeeas ccc tee aoe eee ae 2 10 Beneath this lies a whitish sandstone rock with brown stripes and other measures overlying the only bed of good coal, which is worked at a depth of thirty-five yards below the limestone. In the works at Uffington an effort was lately made to find the lowest of the two coals, which in so many parts of this district occur below the limestone ; but like the upper coal it proved to have thinned out and disappeared, for at a few yards beneath the coal, 1 In this and other sections descriptive of shafts the sides of which were not open to inspection when I ex- amined this country, I am compelled to use the terminology of the miners. The red clods here alluded to are the argillaceous (often saponaceous) mar/s, which form the beds of passage from the Lower New Red into the carboniferous strata. ; UFFINGTON, DRYTON, AND OTHER COLLIERIES. 93 the trial shaft reached the purple schistose greywacke (Cambrian) inclined in nearly a vertical position. A slight acquaintance with the mineral structure of this part of the country would at once have checked the further prosecution of a work which had reached the lowest rock, the fragments thrown up at the mouth of this shaft being identical in structure with the adjacent rock of Haughmond Hill; but notwithstanding such palpable evidence the speculator continued to sink for fifty additional yards in these ancient beds, and was surprised that no change of metal was met with, though the youngest geologist would have told him that no change could occur where strata, of infinitely older date than any connected with the carboniferous system, were in a vertical position. To point out more clearly the folly of this and similar attempts I annex a small general section of this little carboniferous patch, showing its relations to the ancient and barren rocks on which it rests. (See section, Pl. 29. fig. 6.) The coal strata here dip north-north-west at a slight angle, and, as appears in the diagram, they are subject to many faults, the chief of which run from north-north-east to south-south-west. From Uffington we must travel some miles to the east or south before we reach any other patch of coal, the intervening tracts being occupied either by old Cambrian rocks rising to the surface, or covered by the lower members of the New Red Sandstone and great accu- mulations of gravel. It is probable, however, that on many points the coal has never been deposited, since we occasionally see the Lower New Red Sandstone reposing directly upon the older rocks. One small deposit is found at Dryton, on the south-western slope of the Wrekin; and in the more superficial parts of it, near Longwood, coal was long ago extracted; but it has more recently been followed to a greater depth at the former place, where two seams are now in work. ‘The shaft is thirty yards deep, eighteen of which are sunk through overlying detritus of red sand and pebbles, &c. The uppermost of the beds of coal is two feet, the lowest three quarters of a yard thick, se- parated by clods and sandstone, and there are no traces of the limestone or of the third bed of coal. The dip is three inches in a yard to the south-east. On the south bank of the Severn, the bay formed in the older rocks between the ridge of the Caradoc on the east, and Lyth Hill on the west, abounds with carboniferous patches, which vary in the amount of their productiveness, precisely in the ratio of the depth at which the underlying rock is found. For example, at Cound, Pitchford, and other places, where these old rocks (Upper Cambrian) occasionally protrude to the surface, the adjacent carboniferous strata are mere shreds, sometimes covered by the newer Red Sandstone, but towards the centre of the trough the coal strata thicken, and at Le Botwood, near Longnor, we again meet with nearly the same development as in the Pontesbury field. These beds dip east-north-east 10° or away from the contiguous promontories of older rocks. The shaft at Le Botwood is sixty-three yards deep, passing through shales, limestone, and coal. The shale or roof of the coal is particularly rich in plants, and those which I collected were identified by Professor Lindley and form part of the list previously given. | 7 M 94 LE BOTWOOD LIMESTONE AND COAL. The limestone at Le Botwood is extensively burnt for lime and is identical with that of Pontesbury and Uffington, containing also the Microconchus carbonarius. It is about two yards thick and lies from eighteen to twenty yards below the surface. A three-feet bed of coal, found at eleven yards below the limestone, is of a sulphureous quality ; and six yards still lower is a seam, twelve inches thick, of good coal. In the limestone, besides the usual shells, the remarkable species of fish Ctenodus Mur- chisonu (Agassiz) was found by the very Rev. Archdeacon Waties Corbet; and Pro- fessor Phillips detected, in the shale, remains of the Megalichthys Hibberti, &c. On the western edges of this bay, amid the older rocks, coal has been worked near Pul- verbatch, Wetrains, &c.; and on the eastern side it has been detected, and was partially worked in former days, running up in small transverse valleys towards the Caradoc and Acton Burnell hills. One of the most curious of these thin patches is displayed on the west bank of the brook at Pitchford. The whole carboniferous series is there represented by a bituminous breccia, from ten to twelve feet thick! which is partially covered by the New Red Sandstone, and rests upon the highly inclined edges of a greenish greywacke sandstone (Cambrian rock), similar to that of the Longmynd.' The highly inclined edges of these Cambrian rocks, which rise to the height of only from twenty to thirty feet above the brook, are, on the western side of it, covered with the carboniferous breccia arranged in horizontal layers ; but as the works were abandoned when I visited the spot, I could not observe the junction between these beds and the inclined edges of the older rocks. This breccia is composed of fragments of the under- lying Cambrian rock, on the surfaces of which are casts of ferns and other coal plants, the whole being cemented by bitumen and decomposed sandstone. The beds were formerly much quarried, and the breccia being transported to Shrewsbury, and there subjected to heat, a liquid bitumen was extracted, which, when prepared, was sold as a medicine under the name of ‘‘ Betton’s British Oil.” Contiguous to this quarry is a well, on the surface of which is a constant accumulation of bitumen exuding from the adjoining strata. It will hereafter be shown that where points of trap rocks penetrate the adjacent strata of the Cambrian system there are frequently bituminous exudations near the points of contact. From the preceding details respecting the carboniferous deposits near Shrewsbury, it appears, that the coal was formerly worked in those spots only where it actually rose to the surface ; and that, even at the present day, the speculation has not extended to any considerable distance beyond the mere outcrop. In the small irregular troughs at Longnor, Uffington, Longden, Le Botwood, Pitchford, &c., where it is evident from the nature of the sides of the trough, and also by the shallow depth at which the Silurian and Cambrian rocks are met with, that no coal can exist, further trials would be absurd. 1 T consider the green hard greywacke sandstone in the Pitchford Brook, on which the coal breccia lies un- conformably, to be a part of the upper Cambrian System prolonged from the Longmynd. (See Map.) In the brook Mr, Aikin remarked the intrusion into the schist of a green stone trap. PRACTICAL HINTS CONCERNING THE SHREWSBURY COAL-FIELD. 95 An examination, however, of the country on the south bank of the Severn has convinced me, that coal may be profitably extracted to a certain extent in the tract lying between the Pontesbury and Asterley coal-pits, and the escarpments of the dolomitic conglo- merate, and Lower Red Sandstone of Cardeston and Alberbury. ‘Trials in this district or in the adjoining tract, south-west of Cardeston, could be made at small expense, it be- ing highly probable that if the coal measures are not cut off by the rise of older rocks, which is discountenanced by the form of the country, they are only covered by the thick accumulation of gravel and argillaceous clay which overspreads this depression. At the same time that we give apparent good reasons for finding the thin or upper coal strata within a limited area, it is fair to state, that practical observation militates against the supposition of any great expansion of coal beneath the Lower New Red Sandstone on the right bank of the Severn. In no one of the present works does it appear that the seams of coal become thicker or increased in number when followed downwards on the dip. And although these trials have hitherto proceeded to so short a distance, that no very decided conclusions can be drawn, yet it must be allowed that they weaken the supposition of the thin or upper coal-measures graduating downwards into richer fields. We might, indeed, surmise that this zone of coal, which, judging from the nature of the limestone, was probably accumulated in a lake or near the mouths of rivers, has merely resulted from a very partial accumulation of vegetables upon its shores, and that beyond the drift or range of these small gatherings of wood we should look in vain for a mineral formed out of such materials. It might also be said that as these carbonaceous zones of the plain of Shrewsbury differ so essentially from the largely pro- ductive tracts of coal in the absence of the underlying deposits of carboniferous lime- stone, millstone grit, &c., we ought rather to presume, that the mineral thus wanting in its accustomed associations would be feebly developed. On the other hand, it may be contended, that according to analogies elsewhere, carbonaceous matter formed upon the natural edges of such a basin would naturally thicken towards its centre; or, in other words, that as a certain amount of vegetable matter had been accumulated upon the shores of these ancient rocks, still larger quantities were probably washed down their shelving sides into the depths of a capacious bay or estuary, on the opposite limits of which we actually meet with other and highly productive coal-fields rising from beneath a cover of New Red Sandstone. I do not throw out such suggestions as an inducement to proprietors, north of Shrewsbury, to endeavour to penetrate the thick and massive deposits of which the overlying New Red System is composed ; although it is by no means impossible that a coal-field may there lie hidden, which when the more accessible coal strata in other tracts shall have been exhausted, may prove of value to future generations. Such an inference is rendered more probable by the obser- vations in the next chapter, which show, that a band of coal measures of the same age, passing similarly upwards into the New Red Sandstone, and containing a limestone iden- tical with this of the Shrewsbury plain, distinctly overlies the edges of the most productive mM 2 96 PRACTICAL HINTS CONCERNING THE SHREWSBURY COAL-FIELD. of all the Salopian coal-fields ; and hence it is no strained inference that carbonaceous masses equally thick may also be found expanding beneath this upper coal of Shrewsbury, though most probably at some distance from the outcrop, and if so, necessarily at vast depths under the New Red Sandstone of the plain of Shrewsbury. Observations leading to similar inferences, and extending their application to other extensive tracts in the central counties, will be found in subsequent chapters. Again, however, I would repeat that much caution and many preliminary trials towards the edges of this great basin are required before such speculations are attempted, since it is one thing for the geologist to show the natural position of the coal, and another for the miner to determine where it has been locally accumulated in any quantity worthy of the industry of man. This latter point may be most safely ascertained by following the coal seams upon their dip from the points where they are now known, and if they continue to thin out in their extension beneath the red sandstone, then, indeed, deep sinkings in the central parts of the basin north of Shrewsbury would be absurd. The proofs which will be adduced in the eleventh chapter, of the thinning out of the coal seams of the Oswestry field where they dip under the Lower New Red Sandstone, point to the necessity of much circum- spection in all such operations. Passing from these practical hints, I would conclude with a few general theoretical reflections. ‘These poor and thin stripes of coal measures have been dwelt upon in some detail, and similar patches will again be adverted to in the following chapter, on account of their peculiar character and high geological interest, in aiding the proofs of a de- scending passage from the Lower New Red Sandstone into the Carboniferous System. Constituting the youngest member of that system, they fill up an interval in geological chronology, precisely in that portion of the series in which much obscurity previously existed ; for, with the exceptions in the North of England pointed out by Professor Sedgwick’, it was the prevalent belief of geologists when my researches commenced (1831), that in all other parts of England a great break existed between the New Red System and the coal measures, the phenomena of disruption in the environs of Bristol being assumed as the true types or patterns of the general order. These upper coal -measures of Shropshire are further remarkable in bringing to light, for the first time in Great Britain, a peculiar limestone interstratified with coal seams, and which from its prevalent organic remains and mineral composition I have referred to freshwater origin. Though never exceeding eight or nine feet in thickness, and sometimes dwindling away to two feet, this band is so remarkably persistent, that when followed along all its sinuosities the length of its course is about forty miles ; and even in a straight line from Coedway, near the Breidden Hills, to Tasley and Coughley, near Bridgenorth, where it will presently be described, the distance is not less than twenty-five miles; and yet throughout such a space this little stratum preserves the same structure, and contains 1 See Geological Transactions, vol. ii. part [. ORIGIN OF THE UPPER COAL MEASURES. 97 the same microscopic shell, Microconchus carbonarius. The subsequent discovery by which the limestone of Ardwick, near Manchester, was identified with it, has given to this stratum a considerable additional importance, in carrying out over so wide an area the evidences adduced in this volume of the passage of the coal measures beneath the New Red Sandstone of the central counties’. Besides the zoological proofs of this lime- stone having been formed in fresh water, I have already stated, that in mineral characters it strongly resembles the lacustrine limestone of central France, and I may now add that the origin of the rocks in the two countries is probably connected with similar causes. For as Auvergne is a region which has been eminently subjected to volcanic action during past ages, so its extensive formations of finely levigated limestone are sup- posed to have been the produce of hot springs (the usual attendants on volcanos), holding calcareous matter in solution, and depositing it amid the fine silt of ancient lakes. In like manner the whole of the surrounding region of Shropshire, in which this limestone occurs, is absolutely perforated by intrusive rocks of igneous origin, (see Map) ; and hence it is a fair deduction, that the peculiar limestone of this tract may likewise have been the result of volcanic hot springs. Other analogies will strike those to whom the phenomena in central France are familiar, such as bituminous exudations and sources of mineral pitch which issue from the surface at those points where eruptive rocks pro- trude ; but these comparisons belong more properly to subsequent chapters. Difficult as it may be to reconstruct in imagination the condition of the surface of this part of our island during the period of the coal formations, the limestone and associated beds (whether formed exclusively in pure fresh water or in bays in which fresh predominated over salt water) afford convincing proof of the existence of neighbouring dry land, from which rivers flowed, transporting terrestrial vegetable remains, and entombing them with shells, the greater part of which must, unquestionably, have lived in fresh water. That such streams, however, were near the sea, and that in fact they soon passed into estua- ries, will be presently rendered evident by details of the undeniable alternation and in- termixture of freshwater, terrestrial, and marine remains in Coal Brook Dale, which tract, though only distant a few miles from that under consideration, exhibits a vast expansion of the carboniferous strata; thus leading us to suppose, that whilst the Shrews- bury deposit has been simply formed by streams issuing from the Cambrian and Silurian region, and giving rise to lakes to which the sea had little or no access, the greater car- bonaceous masses of Coal Brook Dale have been accumulated by the same waters where they united to empty themselves into an estuary’. The north-eastern edges of this 1 Mr. Greenough informs me that he has observed a bed of limestone interstratified with coal in Warwick- shire which he considers to be of the same age, but he has not observed any organic remains in it. * A point of high comparative interest attached to these coal-fields of the central counties, is that they contain fossil fishes, mollusks and entomostraca, identical with or closely allied to species abounding in the rich fossil accumulation at Burdie House near Edinburgh, the description of which by Dr. Hibbert justly excited so much attention. Though not, perhaps, quite so copiously charged with) organic remains as 98 ORIGIN OF THE UPPER COAL MEASURES. great marine bay were formed near Manchester, its western margin being marked by the zone of carboniferous limestone which bounds the coal-fields of Oswestry, Chirk, and Ruabon. An inspection of a general geological map of England will indicate the extent of the area, which now appears asa vast trough of New Red Sandstone encircled by carbonaceous deposits. (See wood-cut 4. p. 25.) Further observations upon the origin of these coal-fields occur in the ensuing pages, particularly in the concluding part of the eleventh chapter, where a small map will be found, explanatory of the probable physical geography of this region during the accumulation of the carboniferous de- posits. | the Scotch deposit, the Salopian and Lancastrian strata afford proofs which do not exist in Scotland of their geological place in the order of formations. In England they have been shown to constitute the youngest carboniferous zone, because they graduate upwards into the New Red System. Now, if we are to be guided by the nature of the fossils, we might be disposed also to infer that the beds at Burdie House, where no such strati- graphical proofs exist, and which were once supposed to be of great antiquity, represent after all one of the youngest accumulations of the carboniferous system. Atall events, if we look at the question on a broad scale, it is manifest from the position in which the Burdie House fossils have been discovered, not only in Lan- cashire and Shropshire, but also in Staffordshire, that they appertain to those coal measures which overlie the Millstone grit. (See chapter on the Dudley coal-field.) Mr. Leonard Horner has shown (Edin. New Phil. Journ., April, 1836,) that the mixed nature of the organic remains at Burdie House compel us to suppose, that the carbonaceous strata at that place were accumulated in an estuary and not exclusively in fresh water, although their contents had doubtless been poured forth by streams. This subject will be beter understood after perusing the following pages, particularly the conclusion of the eleventh chapter. CHAPTER VII. COAL-FIELD OF COAL BROOK DALE. Upper Coal and Freshwater Limestone——Lower Coal or productive Coal and Tron field.— Carboniferous Limestone.— Trap Rocks and Dislocations. FROM the thin and slightly valuable carboniferous tracts around Shrewsbury we now proceed to the consideration of the great productive coal-field of Shropshire, in which are found nearly all the members of the carboniferous system. Geologists owe their earliest knowledge of this coal-field to an interesting memoir by Mr. A. Aikin, published twenty-six years ago in the first volume of the Geological Transactions’; and recently a fresh mass of most instructive and curious information respecting it has been brought forward by Mr. Joseph Prestwich. As soon as I found that the last-named geologist was assiduously studying the structure of this remarkable district, I willingly referred all details to his enterprise, being aware that the region over which my inquiries ranged, was too large to permit of minute attention being paid to the intricate relations of this highly dislocated tract. To his forthcoming memoir in the Geological Transactions I therefore refer such of my readers as may require precise detailed knowledge, confining my own observations chiefly to the general features of the carboniferous strata and their relations to the surrounding deposits. Occupying both banks of the Severn at Madeley and Broseley, the principal and most productive portion of this field spreads out to the north of that river in a large trian- gular-shaped mass, the apex of which terminates at Lilleshall. (See Map.) To the south it is flanked by the Old Red Sandstone and upper Silurian rocks ; to the west by a thin zone of the lower Silurian rocks and by the trap rocks of the Wrekin and Ercal Fills. Throughout more than two thirds of its circumference, i. e. to the north-west and east, this tract is bounded and overlaid by the Lower New Red Sandstone ; but the passage from the coal measures into that formation is not so clear as in the Shrewsbury . ‘ Mr. A. Aikin had prepared a vast quantity of geographical data, illustrating the structure of this tract, which he lent to me. With his permission I subsequently placed the maps in the hands of Mr. Prestwich, who has made an excellent use of them. His inquiries commenced after I had pointed out the stratigraphical and zoological distinctions between the carboniferous and Silurian limestones of this neighbourhood, (Steer- away, Lilleshall, Wenlock, &c.) 100 UPPER COAL MEASURES OF COUGHLEY, TASLEY, ETC. field, being generally obscured by accumulations of drifted matter, or rendered difficult of investigation by the numerous faults which run along the boundaries. ‘To these obstacles we may add, that no attempts like that of the Earl of Dartmouth (p. 58.) have yet been made to follow out the coal beneath the red sandstone. If, however, we make a transverse section from the coal works at Donnington across the hills on the east, and pass near to Lilleshall Abbey, we see that where the works are nearest to the line of red sandstone, the coal strata dip to the east or beneath the adjacent sandstone. This coincidence of inclination in the red sandstone and coal measures may be observed at several points between Lilleshall Abbey on the north (see section, Pl. 29. fig. 15.), and Prior’s Lee on the south. Between Prior’s Lee and the banks of the Severn near Madeley the boundary is still affected by faults, but at Rowton near Broseley Mr. Prest- wich has detected a passage from the upper carboniferous strata into the Lower New Red Sandstone, similar to the one described in the Shrewsbury field. The same relations are seen on the edge of a thin and broken zone of carbonaceous strata, which describing a tortuous outline, ranges by Coughley to the Wren’s Nest upon the right bank of the Severn, and is thence deflected by Coal Moor into a low ridge extending from High Trees to Tasley. At Tasley a single thin bed of impure and poor coal is worked by windlasses, at depths varying from twelve to thirty yards. In the overlying strata is a bed of limestone about three feet thick, identical with the freshwater limestone of the Shrewsbury field. A section of these beds exposed in an open work near Tasley gives the following succession. (Pl. 29. fig. 12.) Green and yellow shale, decomposing to stiff clay, passing into a thick ferrugino-calcareous layer ............ 6 0 Limestone, compact and cream-coloured, with Microconchus carbonarius and Cypris. (The rock of Pon- tesbuny and Le sBotwood, see pp. 94 2.97 oon5.5, swescaesedsninestaces «any seousiinnscseseenesuiavece+sscaen seca ery 3 0 BNO RRA OETKER San oeeeade dncun locos sbasnanducdosyd0000530 JoranydbiAnsao be uEtdacaboroudasnds saaebePOs bh osdasobapsaadae 3 0 Sandstone of greyish colour with carbonaceous matter and fragments of plants ...........ssseecsececesereeesees 4 0 Blue bind ‘or carbonaceous shale forming the topilof Coal’ ...c.stccvesesccecsetevestscecvecwsccedsccsscccoscssetaren 270 “SISTINU OVW UDO NTS CO Neher seco Osan oc EEAOEOCD S8G0100001C GOs SOUS UCI JOB at ee GQUULHIUDDaC bas sapbpundecogedocessaasconge. 0 6 CO} ys Ge Aan apTL EX CS OLS SITE oS Seco sao necbopce bJbs600000 ab doce abaRtacoo gh nach oot ange. “onphOC acAnnAbSOAbEdLendgHOOkDanSnSSboeune 0 2 Chole Ganache. @sonConnUhigunonoda ch dunberbhnctionoscnchoucenidandtioss nsHAaCartiod SfSdEcsoandlnooconDga ooo Saboncubaoadoaieannndiceond 1s Stiff mottled red and green shale, depth unproved. This coal contains in some parts thin laminz and veins of white calcareous spar. It is further to be observed that much of the carbonaceous matter is in an uncon- solidated state, exhibiting the matted fibres, leaves, and stems of the plants. This structure, indicating an intermediate stage in the formation of coal, is not of un- frequent occurrence in the upper secondary and tertiary carbonaceous deposits in va- rious parts of Europe ; and although not often seen in the most ancient coal, I have observed it in other parts of Shropshire and also in the Dudley field. The upper coal measures, reposing upon the Old Red Sandstone of Aldenham and Shirlot, dip to the east, an inclination which would carry them directly beneath the Lower New Red Sandstone of Cantern Bank and Astley Abbots if they were not met by the prolongation of what Mr. Prestwich LOWER COAL MEASURES. 101 has termed the main fault. Thin patches of coal, similar to that of Tasley, occur at Caughley and at Kingslow, in both of which places the same band of limestone, four to five feet thick, occurs overlying the lower coals and rising almost to the surface. The beds dip to the east at Kingslow and to the north-east at Caughley, and on the whole may be said to have a slight easterly inclination. We thus find this very remarkable band of freshwater limestone in situations more than thirty miles from its western termination near the Breidden Hills, again associated with coal and passing upwards into the Lower New Red Sandstone; and hence it is clear, as inferred in the last chapter, that we must consider the zone to which this lime- stone is subordinate, as the youngest member of the carboniferous series. Neither the coal, limestone, nor any one of the associated strata in these deposits is of great per- sistency, but each of them thins out and reappears at intervals. The poor and detached coal-bearing strata to the south of Bridgenorth, which dip away from the Old Red Sand- stone, and have been already alluded to as rising conformably from beneath the Lower New Red Sandstone of Chelmarsh, are for the most part of the age of those at Tasley and Caughley, and will be subsequently described 1 in conjunction with the coal measures of the Forest of Wyre’. Lower Coal measures or productive Coal- and Iron -field. —After this supplementary ac- count of the strata composing the upper coal measures described in the previous chapter, and to which the attention of geologists has never yet been sufficiently directed, the fol- lowing very brief sketch of the lower or great productive mining portion of this valuable tract may be sufficient ; for, it is not easy to give a very precise notion of the structure of this portion of the field without entering into a variety of details foreign to my purpose. The labours of Mr. Prestwich, however, teach us, that the mineral cha- racters of the same strata often change completely within very short distances, beds of sandstone passing horizontally into clay, and clay into sandstone ; that the coal seams wedge out or disappear; and that sections at places nearly contiguous, often present the most marked lithological distinctions. ‘These observations, which: coincide with my own in various other coal-fields, demonstrate the hopelessness of determining the respective ages of such rocks in different localities by shaft sections, or a mere com- parison of their mineral characters. Even the coal itself constantly tapers away and disappears amid the shales and sandstones, constituting what are locally termed “‘Symon- faults,” the character of pic as Cea guia from true faults, is explained in the 1 Mr. Prestwich has ened me that a shaft has recently been sales near Broseley, which after passing through ninety yards of slightly productive upper coal measures, reached a bed of limestone four yards thick, identical in structure gal and containing te same oerosvonie shells as, the Ue limestone. (April, 1837.) It would seem from Mr. Prestwich’s observations that the small patch of carboniferous sandstone and shale with a thin seam or two of impure coal which occur at Shirlot on the southern edge of Willey Park, sur- rounded by and reposing on the Old Red Sandstone, does not belong to the upper but to the lower coal measures. The sandstone on which Shirlot monument is built is a good example of the lithological structure of many of the lower coal rocks. a N 102 LOWER COAL MEASURES. annexed wood-cut. The vertical or highly inclined lines (a.) (a.) are true faults, the ends of the coal seams (0.) (6.) are ‘‘ Symon ” faults. 1 A section of the Hill Lane Pits near Madeley may be given as an instructive example of the suc- cession in one spot where the strata are pretty fully developed. In a shaft two hundred and thirty yards in depth, we are presented with twenty-one carbonaceous beds, of which the eleven upper- most are sulphureous andimpure. Upper coals, similar to those at Caughley and Tasley, alternate with clays, marls, sandstones both argillaceous and calcareous, and with calcareous breccia or con- glomerate. Some of these beds may represent the upper coal measures of Manchester. The lower coals, or those extracted for use, which in this shaft are reached at a depth of about one hundred and ninety-eight yards, are named in descending order. ft. in WV AS CIC Oalia.. cs cosueatueiws sutstronscteteeneess AS OHNNOHABHNS GAIN BAGCL nr bodiccanosorer 1 Zevlwo=t00t Coal, .isercesencsoerecdduceesoo ness haSbosoADO Maou pa stontanteeiat er estensescanesstects ik fs} 3. Little-Ganey SPSASCCEDIO DACA staieae sacs fe Weciee st talees Wasvesiulcnesieriscrecseesreserievreste 0 7 4. Lower-Ganey ...... slstaleler'ataeleisjete/tisirainis safatcteital sie stuts Ac Obanrionancpanade Raaftiole lech er sis ay -ctoters 1 6 Os bestiCoalectassnar: aieis slo 06 ginaieraie nialetert e's sl'cslsteite oiteiarsTictia oa a Rae ais tuaeia OCs a aie sichees ote aiars sesstee 2 5 G-wHandle; Coalewwescacenestconnccatsstmr ce aaneot. sadensnse onriants casei cumemes economies aS iis WlodeC aliens kee Mensatnd. Sooke teeter rss de catducecdeeteteiee the mene trethneoh nee aeeeaen 1 4 8, Little Flint Coal........... aiafatasiere a eerarOMTN's Ovace ofsjep oieale[eiv cte'nlteiaieloiha ctelve'sk o's acted ratte os dateleieis art 2G O:aCoalnunden:Grawstones wc. ones ccansctessadeanewstavcescterecsterentecsetreaea sane tenoee eats 1 0 Oe Wancashive *Wadics Coal’ nactnec.sesstsoctaneigerccs estes cosuecttansstannteerccwaeoeentete 0 9 Total of good Coal in this shaft...... 15 11 In the above list the beds which separate the seams of coal are omitted. The following table will explain to the reader how little the beds of coal are persistent, and how much they vary in their dimensions in different parts of the field, the united thickness of the mass of coal in any one shaft never being dependent upon the number of the seams. Pits. Thickness of Coal. No. of beds of Coal. yds. ft. in. Hadley. cartons eats date cuan disesens caerse TOWO! (OM. Me diatess sataehcariaeeeniee abaeeess 16 Snedaghill: ~.z-thans; b.seqesua ths ceteens saetes 1 ean mar nmpca Mra atrcs Goad. ec 12 Mialimsleesr in auc anti: cussactiovasmarerenciistss LPT SO SLO re tas weertatsante dan adoaenmicngnicdennn dct 13 IDE Yeas 12 Theis oba punbioneocapcncogpoocnnoctine ts TO 2A) “Ee ndoddosnanandioncos patel asietdesaste tare 11 DA WICY x acres tte a dateen taasneasatis cis Seer dt OC) oh dadtnndin ser meerinonadancie cme cndeene 16 ie litm OOrg Sasiveeccheenaccere meen taaee Te A OW angonenonsack och udnbag ngoiteetusnatiods 17 Madey As ncsints sahasc amen entaee OD 2 WO issreuceeiseedsaideraceadininaeun cae ecaecees 24 (21 to 24.) Broseley ....... Rn nga noottnoIn aoeeeanNiMOSHaL Te OU “BPs caponns aalalergieareay daterticescace slats eetrebetiat 13 The ironstone so largely worked in this field is both concretionary and flat-bedded, but for the 1 In this table all the coal seams, of whatever quality, are enumerated. In other sinkings, as at Madeley Meadow Pits, as many as twenty-seven seams of coal of pure and impure quality have been passed through. ORGANIC REMAINS. 103 most part in the former condition, and the various courses of it are known under these names: New Mine (peculiar to Madeley) Crawstone, and Pennystone, occurring generally: White and Blue Flats, in the north and middle districts ; Chance Stone and Yellow Stone, in the middle tract; Ball stone, Brick stone, and Blackstone, in the northern district. The Ragged Robins and Chance Pennystone are of irregular occurrence. Of these twelve courses of ironstone more than seven are never found in one locality. In taking a general survey, it may be said, that both the coal and iron are much more abundant in the northern than in the southern part of the field. Mr. Prestwich has indeed remarked the difficulty of identifying any particular stratum of the upper portion over a con- siderable area, whilst he has found the lower measures stronger and more persistent. - Among the various rocks which alternate with the coal and iron, the stone of the Willey or Shirlot obelisk is an example of a coarse variety, while the sandstone occurring immediately above the “ flint coal”’ is of remarkably fine quality for architectural purposes, the monument erected to the late Duke of Suther- land on Lilleshall Hill being built of it. Some of the grits associated with the lower coals pass into coarse conglomerates containing fragments of quartz rock, trap, Silurian and Cambrian rocks ; and in the lower measures some of the beds of shale afford excellent fire clay, long celebrated in the manufacture of pipes and pottery. The ores of iron are peroxides in the sandstone, argillaceous carbonates in the shale, and sulphurets in the coal. The sulphuret of iron is the most abundant mineral, and next to it the sulphuret of zinc or blende, which appears in the ironstone nodules of the Pennystone measures both in granular and crystallineform. Petroleum is of constant occurrence in the upper as well as lower measures; the chief source of this mineral at Coal Port, which formerly afforded one hogshead per diem, being in a thick-bedded sandstone of the upper measures. This supply has, however, much decreased with the opening of the new coal works. Other tar wells have been discovered in the lower coals at Prior’s Lee. In some pits, as at Dawley and the Dingle, the petroleum exudes in such quantities that the works are necessarily boarded up or “‘plated”’ to prevent its infiltration upon the workmen. Besides these minerals titanium exists in the iron ore, crystals of it having been detected in the refuse slags. The general relations of the carboniferous deposits to the contiguous formations are explained in Pl. 29. figs. 11 and 16. Organic Remams. To the zeal of Mr. Anstice, of Madeley, in collecting the varied and curious or- ganic remains of this coal-field, geologists are signally indebted. Although acquainted with the riches of his stores, the use of which he liberally offered to me as far back as the year 1832, I felt that these numerous and beautiful specimens merited the attention of a separate historian. Shortly after, the district falling under the notice of Mr. Prest- wich, the desired object was attained, and all the most characteristic of the unpublished fossils will, I trust, shortly appear in his memoir in the Geological Transactions. The collection formed by Mr. Prestwich, both by his own exertions and the contributions of Mr. Anstice and others, is very numerous. The terrestrial plants alone amount to between forty and fifty species, composed of Euphorbiacee, Dycotyledons of doubtful affinity, Palme, Monocoty- N 2 104 ORGANIC REMAINS. ledons: of doubtful affinity, Equisetacee, Filices, Lycopodiacee, &c., the greater part of which are figured in the British Fossil Flora by Messrs. Lindley and Hutton, others by the foreign fossil bo- tanists, Sternberg, Adolphe Brongniart, &c. Of these the Stigmaria ficoides, Newropteris cordata, Odontopteris obtusa, Pecopteris lonchitica (see wood-cut), Lepidostrobus variabilis, and Sig wlaria Murchisonit are common to this and other coal-fields in Shropshire}. The animal remains consist of Fisues, three genera, viz. Gyr acanthus formoss, Megalichthys Hibberti, and Hybodus?, of Agassiz. | : Crustacea, Cypris; Limulus trilobitoides (Buckland). rilobites; three small species, un- described, and dissimilar to any individuals of this family, which we shall afterwards point out" in such great abundance in the rocks of the Silurian System. | ConcHIFERA AND Moutuusca. Upwards of forty species, among which are two beautiful spe- cies of Orbicula, Productus scabriculus (M. C. t. 69. fig. 1.) ; Unio, two or three species; Spirifer, three species; Nautilus, four species; Ammonites (Goniatites?), two species; Bellerophon, two species; Cirrus, two species; Orthoceras, one species, &c. Most of these organic remains have been already figured in Phillips’s Geology of Yorkshire, vol. ii., or in Sowerby’s Mineral Conchology, as species belonging to the Carboniferous or mountain limestone. The published and unpublished species all differ from the fossils hereafter to be described m the Silurian System. In addition to these fossils, Insects have also been found in ironstone concretions, the specimens of which are in the cabinet of Mr. W. Anstice. These are noticed by Mr. Prestwich, and two figures of them have subsequently been published by Dr. Buckland in his Bridgewater Treatise as Curculionide, most resembling (according to Curtis and Samouelle) African and South American types. Dr. Buckland has with great propriety named one of these Curculionides Ansticit, the other C. Prest- victt, vol. 1. p. 76. The wing of the insect represented in the wood-cut on the next page has been furnished by my friend Dr. Mantell, in whose rich museum at Brighton it-may now be seen. It was previously supposed to be a plant, and was sent to M. Adolphe Brongniart, who immediately perceived that the transverse nervures were unlike anything in the vegetable kingdom, and on being referred to M. Audouin it was pronounced to be the wing of a neuropterous insect closely resembling the living Conk dalis of Carolina and Pennsylvania. - This copious list of fossils enables us to speculate with some ¢ security on the probable conditions under which the various strata of this coal-field were accumulated. Here we find the forms of many terrestrial plants, and even of insects, entombed amid a variety of shells and some crustaceans, the greater part marine, but others, such as the Uniones and Cypris, unquestionably of a fluviatile origin. The precise relations of the alternating beds containing these various remains are well explained by Mr. Prestwich. ‘ Dr. Du Gard has collected many beautiful fossil plants from this coal-field, particularly large stems, many of which, together with specimens derived from Mr. Anstice’s collection, now form part of the museum of the Natural History Society of Shropshire and North Wales, recently established at Shrewsbury.. 1 CARBONIFEROUS LIMESTONE. 105 13. 4 aN yy NN In this wood-cut are four figures selected from the mass of fossils to indicate the mixed nature of the deposit, viz. The wing of the insect mentioned in the previous pages: its actual size is repre- sented in fig. a. A land plant, fig. b., Pecopteris lonchitica, Brongniart, (Lindley and Hutton, Foss. Flor. vol. ii. pl. 153.) A fluviatile shell, fig. c. (Unio acutus), Sow. M.C. t. 33. f. 5, 6 and 7. A well-known marine shell, fig. d., the Productus scabriculus, Sow. M. C. t. 69. fo: Ie | Doubtless, therefore, as hinted at in the preceding chapter, this tract of Coal Brook Dale must originally have been a bay of the sea, into which streams of freshwater dis- charged materials derived from those lands, the contiguity of which has been previously inferred from the existence of freshwater limestone in the adjacent coal-fields. This view is also quite in accordance with that of Mr. Prestwich, who is of opinion, ‘that the alternations of freshwater shells with marine remains, do not prove as many relative changes of land and sea; but that the coal measures were deposited in an estuary, into which flowed a considerable river, subject to occasional freshes ; and he conceives that this position is supported by the fact of frequent alternations of coarse sandstones and conglomerates with beds of clay or shale,’ containing the remains of the plants which have been brought down by the river. (See the positions (c, c.) where such estuary accumulations were formed on the shores of the ‘‘ mare carboniferum,”’ repre- sented in the small map, Chapter XI.) (c*.) is the site of Coal Brook Dale; (a, a.) the supposed lakes in which the freshwater limestone was deposited. | Carboniferous Limestone.—It might be expected that as we descend in the series of strata, we should next meet with the great arenaceous formation, called the ‘‘ Millstone Grit,” which forms the substratum of many other coal-fields, and of which abundant ex- amples will be adduced in the ensuing chapters. But in truth, there are here scarcely any rocks which can be referred to that deposit, unless we consider as its representatives, the grits, conglomerates, and sandstones which form the lower portion of the coal 106 CARBONIFEROUS LIMESTONE OF STEERAWAY, ETC. field; and which contain seams of coal and courses of ironstone almost to the very base of the arenaceous strata. These arenaceous strata rest in several localities upon the true carboniferous or mountian limestone. As this limestone, however, has no great range, and is not of large dimensions, the coal-field throughout the greater part of its extent, reposes at once upon other and older rocks, chiefly of the Silurian System, and in the southern district upon Old Red Sandstone. (Pl. 29. fig. 11.) The carboniferous limestone rises from beneath the coal measures at Little Wenlock, to the north-west of which this limestone appears at Oldfield works, and ranging thence by the Hatch Bank to Steeraway, extends in a narrow ridge from south-west to north-east, nearly two miles in length. This limestone dips to the south-east at an angle of about 45° in the principal works at Steeraway, where it is burnt for lime. (See section Pl. 29. fig. 16.) The beds, eight in number, have an aggregate thickness of eleven yards, but vary indi- vidually from five inches to twenty-six each, and are associated with strata of impure limestone, shale, &c., amounting in all to upwards of one hundred feet. The limestone is of a very dark grey, almost black, colour, in which respect, and in being very thick- bedded and not of concretionary structure, it is quite unlike the Wenlock limestone of the underlying Silurian System. The distinction between these limestones is rendered still more complete by the organic remains, which are in great profusion at Steeraway, consisting of shells and corals which are characteristic of the carboniferous limestone in many other parts of Great Britain, and never occur in the inferior limestones of the Silurian System. Among these the most prominent are the large Productus hemsphe- ricus and many corals, including Lithodendron sexdecimale, Phillips, (Cladocora, of Ehrenberg,) which is so abundant, that it constitutes massive beds, particularly the layers of black calcareous shale, which divide the limestones. This black limestone of Steeraway is overlaid by a sandstone, which separates it from the productive coal beds, and is underlaid by strata belonging to the lower limestone shale, consisting of lightish yellow sandstone, with layers of impure limestone and shale, which are interposed be- tween it and the trap rocks of the Ercal and the Wrekin. Allthis portion of the edge of the coal-field is much convulsed, trap rocks intruding at many points, so that a patch of the limestone is found adherent to the trap in the village of Little Wen- lock, and the mass at the Hatch Works is quite broken off from that of Steeraway. (See Map and Pl. 29. fig. 16.) Limestone, similar to this of Steeraway, was discovered below the productive portion of the adjoining coal-field at Lawley, distant upwards of one mile from the natural outcrop of the rock. It had apparently thickened upon the dip and had become much less inclined. This underground mass was extracted for some time, but the works are now abandoned. The north- western edge of the coal-field is marked by a powerful downcast fault extending from the end of the Steeraway and Ercal Hills to Lilleshall, by which all the lower strata are lost, the productive coal measures abutting against the New Red Sandstone for a distance of nearly five miles. Along this line the coal measures plunge to the north-west, unlike those at the edges of the coal-field at Steer- away, Little Wenlock, and the Iron Bridge, where they dip to the south-east. It has, however, been ascertained by Mr. Prestwich that this north-west dip is only partial, and that the coal strata CARBONIFEROUS LIMESTONE OF LILLESHALL. 107 rise again with an inclination to the south-east, the flexure being caused by the line of disturbance which proceeds from near Steeraway to Lilleshall, and along which indeed there are traces of the limestone being upcast, accompanied at one spot (the bottom of Hadley inclined plane) by a knoll of trap. (See Map.) On the north-eastern and northern face of the trap rock of Lilleshall Hill, the carboniferous limestone is again brought up, and appears on the sides of the roads and in some old works extending to the high road from Wellington to Newport. It here folds over, or rather is broken up by an anticlinal line proceeding from the trap rock, and by which the limestone itself is thrown into a saddle, dipping both to the east and west. The prevailing dip, however, is to the east-north-east, by which inclination the lime rock is carried rapidly underground, disappearing beneath certain white and red carbonaceous sandstones with impressions of coal plants. The limestone of Lilleshall is extracted by shafts upon the dip to a distance of more than a mile from its outcrop with a prevailing easterly dip; the deepest shafts (those near the village of Aston) being one hundred and twenty yards. The succession of most of the limestone beds can, however, be best studied in the old open works near the basset. The following is the section, in descending order, of all the strata. 1. Red sandstone, a good freestone, with impressions of coal plants. This rock, which is traversed by the new shafts, is a variety of the millstone grit, similar to that which will hereafter be described at Sweeny near Oswestry, and at Cromhall near Tortworth, Gloucestershire. (Upper limestone shale of Conybeare and Buckland.) 2. Sandstones of purplish pink and white colours, with a few impressions of stems of plants. Thirty to forty feet of this rock are seen at the old open works. These pass down into a very thin flaglike fine-grained sandy limestone, spotted with dark grains of brown oxide of iron; there are also a few small geodes of iron as large as apricots. c. Yellow and red shale. d. Grum. Dull dark red and green impure concretionary limestone, in parts ferruginous, each geode being enveloped in red shale. The Productus hemisphericus and another species are most abundant, together with the corals Litho- strotion floriforme (Fleming), Syringopora reticulata (Goldfuss), and Lithodendron irregulare (Phillips) (Cladocora, of Ehrenberg). This mass is about twenty feet thick. e. Flat-bedded greyish-green limestone of about a foot in thickness. f. Partial wayboards of red and black shale. 14. Observing the organic remains in this portion of the quarry, I was struck with the regularity of their arrangement, but especially in the case of the large coral Lithostrotion (Lhwydd), L. floriforme (Fleming), represented in the above wood-cut'. This coral y, y was two feet five inches wide, by one and a half feet in height. The 1 From the position of the coral represented in this wood-cut, the generic and specific characters cannot be distinguished. The coral was first determined by Lhywdd as early as the year 1699, and has subsequently received the following names from other naturalists. Hrismatolithus madreporites (Floriformis) Martin. Pet. 108 CARBONIFEROUS LIMESTONE OF LILLESHALL. lower parts were rooted in the shale (f), whilst the upper passed up through the bedded limestone e into the mass of red concretions, or “‘grum,” d. It appeared, therefore, to be precisely in its original position, and conveyed the impression that it had remained undisturbed beneath the sea, whilst fine red sand at one time, and mud with calcareous matter at another, were deposited around it. Fig. * of the wood-cut, represents the large shell Productus hemisphericus, and gives by comparison an idea of the great size of the coral. | / | The section continued, in descending order, consists of g. Splothers, red small concretionary limestone and shale, much resembling the “ Grum.” h, Bulls’ Livers, concretions rather larger than the “ Splothers.” All these overlying beds were formerly worked for lime, but are now abandoned. 2. Red and black shale. Jj. Strong-bedded pinkish red sandstone, with a few pebbles of white quartz. Some of these contain lime in the cement, and are therefore calcareous grits. His LCG SONG. aa casters | These constitute the solid subcrystalline mass which is now the chief mine, and which the Ls Captainer ...catissecesss | workmen call the upper measures. They vary in colour from light cream-colour to grey and IMMNGGS Gensedectsa eras asin red, and contain nearly the same fossils as the overlying beds. They are all worked underground M. Strong StONC...sreereers in a thickness of about eight yards, separated only by very thin wayboards. The shafts upon 0. Bottom or white stone. | the dip have not been sunk beneath the floor of the “ white stone.” p. Strong-bedded pink and red sandstone, with white quartz pebbles. q. Lower or Grey-limestone. This rock, from ten to twelve yards thick, is only seen on the rise of the strata to the northern end of Lilleshall Hill, where it crops out. Like the other measures it is so associated with red and green shale, in parts micaceous, that in the old open works a casual observer might conceive that the beds belonged to the New or Old Red Sandstone. On fracture, however, it proves to be a dull grey flat-bedded limestone with a purple tinge, gritty, earthy, and impure. Though it did not appear to contain the Productus hemisphericus of the upper beds, I found in it some well-known corals of the other beds of limestone. This Lilleshall deposit has been described in some detail, because it differs es- sentially in many of its mineral characters from any of the varieties of the carboni- ferous limestone, described in the sequel. The organic remains, however, clearly belong to this formation, and are completely distinct from any which occur in the overlying or underlying systems. This is particularly marked in the above-named corals, which I have the authority of Mr. Lonsdale for stating, are unlike the corals of the Silurian System. On the edges of this coal-field, therefore, we are presented with a beautiful illustration of the superior value of organic remains to mineral characters in identifying the age of rocks; for at Lilleshall the carboniferous limestone consists of red and green, and light grey limestone, with abundance of red concretions, in parts strongly resembling the ‘‘cornstones” of the New and Old Red Sandstone ;. whilst at Steeraway, only five miles distant, it is a black, dark grey, thick-bedded rock, and void of all concretions. In the one case the associated sand- Derb., Pl. 48. fig. 8 and 4; Stylina, Parkinsons Columnaria floriformis, De Blainville ; Astrea mammillaris ? Fischer de Waldheim; Lithostrotion floriforme, Fleming; Cyathophyllum floriforme, Phillips. Mr. Lons- dale is of opinion that this coral ought to retain the generic name of Lhwydd, which has been adopted by Dr. Fleming. aoe 2 TRAP ROCKS. 109 stones and shales are red, in the other they are white, or yellowish white, and black ; yet notwithstanding these discrepancies in structure and in colour within so short a distance, the limestones of Lilleshall and Steeraway are geologically identical, and were doubtless formed during the same period and in the same sea, for they contain similar marine shells and corals, and occupy precisely the same place in the series ; that is, they are overlaid by and graduate upwards into those sandstones and gus Feliiali form the base of the productive coal-field. The carboniferous limestone is the base of the system under consideration. The characters and relations of the other deposits which lie beneath this coal-field will be explained in a subsequent part of the work; and I shall here merely state that the carboniferous limestone has not in this locality any regular downward passage into the Old Red Sandstone as in other districts. Onthe contrary, the Old Red terminates at the southern end of the tract, and has never been found beneath the coal measures or mountain limestone on the north bank of the Severn ; the underlying stratified rocks throughout the productive coal-field consisting of various members of the Silurian System. Of these the Wenlock limestone or second formation of that system is much the most conspicuous. Rising to the surface on both banks of the Severn, it is pre- sented in juxtaposition to the carboniferous limestone ; so that the geologist contrasting the two rocks, can at once perceive their dissimilarity both in lithological structure and organic contents. Besides these stratified sedimentary masses, there are, however, other rocks of cry- stalline structure and amorphous forms, (the trap rocks of geologists,) which in a pre- vious chapter have been shown to be of volcanic origin. (p. 68.) Trap Rocks.—The Wrekin may be called the great centre of volcanic action in. the proximity of Coal Brook Dale, but the consideration of that elevated mass is neces- sarily postponed, until the nature of the strata through which it has been erupted has been explained. In the mean time I simply allude to the Wrekin, because the trap rocks of the coal-field on its eastern flank, might seem to be closely connected with it. The volcanic agency, however, by which these contiguous masses were erupted, was in activity at different periods. That which gave rise to the Wrekin, took place during and after the accumulation of the Silurian System, the strata composing which were thereby thrown into inclined positions, before the sedimentary matter composing the carboniferous system was elaborated. At a subsequent epoch, and long after their consolidation and completion, the coal measures were in their turn pierced and tra- versed by other intruding masses of trap, differing in mineral characters, but erupted on contiguous lines of fissure parallel to that of the Wrekin. These latter outbursts specially relate to the present subject, and I may therefore say a few words concerning them, although the reader will better comprehend their origin and connection, when he shall have perused the chapters in which the more ancient phenomena of the same class are described. 110 DISLOCATIONS. The western side of this coal-field, is most marked by the protrusion of trap. This rock juts out in bosses of irregular shape at and about the village of Little Wenlock, between seven and eight hundred feet above the sea, surrounded by broken layers of carboniferous sandstone and limestone. The most prevalent variety of this trap is a hard crystalline, dark-coloured rock, which may be called basaltic greenstone, though in some cases the grains of felspar are with great difficulty distinguishable from those of hornblende, and then the mass must be considered basalt. Olivine is here and there an ingredient, and in one of the hummocks at the Horse Hays, nearer the centre of the field, the rock contains prehnite, while in the western limit of the tract, there are greenstones of a coarse grain which pass into tufaceous amygdaloids. Wherever these basaltic rocks appear, the contiguous strata of the coal-field are much dismembered. This is seen not only on and near the surface, but has been proved by numerous underground workings, the full details of which will be found in Mr. Prestwich’s memoir. It is sufficient for the present to state, that the trap of this field is very similar to that which in subsequent chapters will be described at greater length, as bursting through and dislocating the coal measures of other tracts, particu- larly in the Clee Hills, where the phenomena of this class being much more striking will be explained at greater length. This brief notice of the characteristic and preva- lent trap rocks of Coal Brook Dale is, however, a natural prelude to a notice of the dis- locations of the strata produced by such eruptions. Faults.—The striking dislocations to which the carboniferous strata of this tract have been subjected, are indeed well accounted for by the protrusion of the above-men- tioned volcanic rocks. Referring my readers who desire further details to the valuable memoir of Mr. Prestwich, I shall here do little more than direct their attention to the principal lines of fault as laid down upon the map, and to the diagram, Pl. 29. fig. 16., which explains some of the principal fractures. Mr. Prestwich has well observed, that there is probably no coal-field of equal size in the kingdom which has been so greatly shattered as this. It has, in fact, been powerfully elevated from beneath the sur- rounding Lower New Red Sandstone in separate wedge-shaped masses, the apices of which terminate at Lilleshall and Newport. The longitudinal lines of fault by which the field is thus cut up, run nearly from south-west to north-east, and when viewed on the map, resemble the sticks of a slightly expanded fan, the handle of which is the trappean hill of Lilleshall (to be described in the sequel). These lines of greatest frac- ture are also traversed by cross faults of minor importance, trending from east to west, and north-west to south-east, &c. The most powerful of the longitudinal faults is that which bounds the coal-field, on the east, and separates it from the Lower New Red Sandstone. The coal-measures along this line are not less than one thousand feet thick, and as some of the lower seams of coal are thrown up to the level of the overlying strata of the New Red Sandstone, this upcast (the main fault of Mr. Prestwich) is thus shown to have exceeded one thousand feet, though to what further extent has not yet DISLOCATIONS. 111 been ascertained. Again, in the centre of the field, the masses have been so elevated, that the very lowest beds of the coal measures are brought to the surface, all the supe- rior strata having been destroyed and denuded. The most powerful dislocation within the field is called the Lightmoor Fault, and is an upcast of more than two hundred yards at the point of its greatest intensity ; but it appears that the strata are unequally dislocated at different spots, even along the same line of fault, and in some instances the change of level would seem to have been the result of a series of small dislocations. General reflections on these phenomena will be offered, as soon as my readers have become acquainted with the more ancient deposits of this neighbourhood, and the various volcanic products with which they are associated. I now restrict myself to the observation, that the north-easterly and south-westerly direction of these faults and basaltic outbursts is parallel, to the fissures along which the Wrekin, Caradoc, and other trap rocks of more ancient date have been erupted, and also to the lines along which the Silurian and older sedimentary formations have been elevated. CHAPTER VIII. CARBONIFEROUS SYSTEM (continued). Clee Hill Coal-fields ; including the Titterstone Brown Clee; with descriptions of the underlying formations of Millstone Grit and Carboniferous Limestone. THE Clee Hills consist of two Separate mountainous masses, the most southern of which, called the 'Titterstone Clee, lies upon the confines of Salop and Hereford, five to six miles east of Ludlow; and the other, or the Brown Clee, is nine to ten miles north of that town. The summit of the latter is 1806 feet, and that of the former 1730 feet above the sea. ‘These hills, chiefly composed of carboniferous strata, are surrounded by Old Red Sandstone, and he contiguous to the Silurian rocks which form the special object of this work: As they have not hitherto been fully described, it is essential to dwell upon them at some length. The summits of these ridges are, for the most part, formed of hard and pure basalt, locally called ‘‘ Jewstone”’, which being spread over a large portion of the coal-bearing strata in thick tabular masses, is pierced through at many points by shafts for the ex- traction of the subjacent coal. In the sequel it will be shown, that this basalt has risen up through the carboniferous strata, and has then overflowed their surface. Let us, however, now proceed to view the mineral composition and general relations of the coal measures of these hills, beginning with those of the Titterstone Clee’. Coal measures of the Titterstone Clee.—Under this term are comprehended all the carboniferous strata which adjoin the Titterstone Clee Hills, and the limits of which will be seen in the map. Within this area lie the fields of Cornbrook, Treen pits, Knowlbury, the Blue stone, the Gutter, and Horse-ditch. All these so-called fields belong, however, to one and the same carboniferous tract, which is of an extremely irre- gular outline, and is, in fact, divided into several masses, one of which lies in a very 1 The Clee Hills have been partially described by Messrs. Robert and Rowley Wright, attached to the Ord- nance Survey, who also made a geological map of the environs of Ludlow, embracing these hills. Though executed before I had worked out the subdivisions of the Silurian System, this map, which is now deposited in the library of the Geological Society, is very accurate in its general features. TITTERSTONE CLEE COAL-FIELDS. 113 perfectly-formed, small basin. ‘The whole of the space which is marked by a dark colour upon the map is not, however, a productive coal-field, but includes those sand- stones and millstone grits which support the coal, and which in this and all the other districts cited in this work, are unproductive of coal’. The coal-field is flanked on two sides by zones of carboniferous limestone rising from beneath the millstone grit, and the base of the series is the Old Red Sandstone, which wraps entirely around the tract, separating it on the north from the coal-field of the Brown Clee, on the west from the Ludlow rocks, and on the east from the coal-fields of the Forest of Wyre. (See Map and sections, Pl. 30. figs. 1 and6.) Thus the coal measures of the Titterstone Clee are in portions of their range based upon those rocks which in other parts of England com- plete the succession of the lower carboniferous strata. That portion of the field known by the name of Cornbrook, forms an elevated trough, capped by a plateau of basalt. To the south-west of it, and at a considerably lower level, is the small basin of elliptical form, called the Knowlbury field (PI. 30. fig. 7.), which is distinctly broken off from the great field of Cornbrook ; and hangs, as it were, from the skirts of the more elevated tract. This basin is completely exempt from basalt, except that its surface is partially encumbered with fragments of that rock. The Gutter, Horse-ditch, and Blue-stone works are merely the thin or lower coal seams which crop out at various points beneath the escarpment of the larger and overlying basin of Cornbrook. In those parts of this coal-field which are most fully developed, as at Cornbrook and Knowlbury, there are four principal beds of coal, which vary somewhat in thickness in different parts of the district. In descending order they are known by the names of the Great Coal, Three-quarter Coal, Smith Coal, and Four-feet Coal. Although only four beds of good coal have been proved in any one shaft or vertical section, there is reason to believe that the coal worked at the Gutter, Horse- ditch, and Blue-stone pits is a fifth or still lower band, which thins out to the eastern and southern parts of this field, and is merely worked at detached points upon the out- crop or basset. The uppermost or Great Coal is usually overlaid by a considerable mass of shale and thickly bedded whitish sandstone, known as the “‘ great coal rock”’. Beneath the great coal, the shale contains a good number of concretions of ironstone of excellent quality, usually exhibiting ‘‘Septaria” within, and often containing impres- sions of plants. They are called the ‘‘ Three-quarter ironstone measures,” because they surmount the three-quarter coal. These ironstone nodules are repeated below this seam of coal in the shale beds termed Clumpers. Then follows the Smith coal, so named from its peculiar value in the manufacture of iron. The Smith coal is separated from the ‘‘ Four-feet”’ coal, by a thick mass of sandstone, with many impressions of plants ; 1 The coal-fields in this region differ essentially in this respect from those of Yorkshire and the North of England, where there are not only coal-fields in the millstone grit, and below it, but also in and throughout the carboniferous limestone. 114 CORNBROOK COAL-FIELD. and beneath the Four-feet coal is a hard white sandstone, with red and grey shale. The lowest coal seams repose on the conglomerate and sandstone representing the millstone grit. Such is the general arrangement of the strata, where they are fully developed. The largest and most productive portion of this coal tract, called Cornbrook, is, as before stated, entirely covered by basalt, and the coal is there uniformly worked by shafts sunk through that rock, which varies in thickness from twenty to sixty-four yards. In these works the proprietor, Mr. Botfield, has hitherto confined his operations to the three principal seams above mentioned. The following isa section of the beds passed through in one of his shafts : Yds. Ft. In Basalt; or *ediewstone:’ Slicisevesusassetessigaecsenaiteameanaeoecene ce moaucetee nies 50 1 6 Notion Jewstones,ar dsbrowmeclucly este sssetesceeatee rece races eeeee eee e center 3 0 0 Birethindiorishalememeccssteteta cthsondecr ataceucuncteeaaece tent een eenee eee 3.0 0 edi ot kes wi, Sue's deoaionsies ceferaes oxy 32 cateaatlrs Soamatea aaj yen ta ands cae haces Soc tien 4 0 0 Pine yestOue TOOL IRONSLONE) ievaneenwasaien cynsstenereces seine ream: suceceedace tenets 2 0 0 Pinney stone measures (GrONStONe)\.20.5,...ss0sayeeeeseeerraecessetasasccenvoreone se 3 0 0 Horse-flesh earth (hard clunch of reddish colours) .....secccsccsscssesseeascenss 3.0 0 Rocktandsbindemingled topetheny 2.4.5. .s.0.ceeseenens-seackerweastecaasetsercucaees 10 0 0 LBA TG a SS onisemontipob tong anccihgp dododadé ufiein cobserberada on oedtsbtinndeddatbobonsaraebe 2 0 0 Chance TOCK ansuscessevesuscassesessartraecansiesseaeariees st anccne cansietecasteeseeaecne 8 0 0 Rock"atrdsbindsmingledstogetherm verceceors -svaece cretecereieeeseceetseceetetertts POO Bluciclunveh#.. ceat.b ae cusn scene secu cstntte nencaeuai cua seer See nepasen clea ees eaters Ae 16 Greati@oalirock: (sandstome)) /ancsnnsecdsecasa: seauecn tin eadeaen vac teeeseatesdees OSORNO Great Coalaoor(ishale,scCo) st ndeceen; sip casraancesernentaatisera temo an eelonnes 2 0 0 GREG COG” Freres Wiasectie eee Few oe csesane saaCo a Nhe asa te Sea a ee teeta terete TNT 2 20F 0 Grea taCoalmonmds toners ccs asaedeteneccas ust eantagtavenacrastea tte seeserent serene 2 0 0 Bot fom are chiara sn ogee setae swies jccticescmans cccensemitiess ccvean Umuenae ticcsacee eae eet 1 leG CITE GS. “Gok dosededltsgac sob UochSaonanoacoureBaamoadacdsenar. code xno seopeencndconntio PF all AG ULBIMCOGP wisnasaenensasarentenssCreretitas srcte see et ineet enc eet tet eee Te "6 From the Smith Coal to the Four-feet Coal, 3 yards ... 3 0 0 Hout fects Conte ieccessessuasetotasesdentessets cesearrens Acoceete 1 oto 4 10 129 2°6 The Knowlbury basin being free from the cover of basalt is more clearly exhibited than that of Cornbrook. (See Pl. 30. fig. 7.) Its form is elliptical; the major axis being about a mile in length. On the south and west, it is flanked by the Old Red Sandstone; on the north and north-west, by an elevated line of works in the lower coals, called the Gutter; on the north-east, by an escarpment of basalt and the Treen pits (the south-eastern face of the field of Cornbrook) ; and on the east by the millstone | grit and a band of carboniferous limestone. The inclination of the strata upon the opposite sides of the basin is variable. On the west, the lower beds of coal and sand- stone crop out at angles of about 30°, resting on the Old Red Sandstone. At the south-western extremity an adit being driven from the lower country of Old Red Sand- stone into the heart of the coal works, the exterior or lower carboniferous strata were found in much more highly inclined positions (60° to 70°) ; but the angle decreased as KNOWLBURY BASIN. 115 the beds converged towards the interior of the basin. In the most depressed or central part, termed locally the ‘“‘reen”’, the strata necessarily lie in more horizontal positions. The four principal beds of coal have been regularly worked, and they were all passed through in the adit. The overlying measures will, however, be best understood by consulting the following section made in sinking a shaft 220 yards deep, at the new pit, or nearly in the “‘ reen”’, or centre of the basin. Yds. Ft. In. Yds. Ft. In. PPS Oiler. Aptunhocubago. as crevecccsseccsseccens 2 L 0 Brought forward.eocccsssees 133 2 0 IT. Soft yellow sandy rock ......cccceseseees 5 0 0 AOCIV Ee BIN iwstecsscesenurcem@eaecstin oF 0 O III. Blue. Pinny ironstone measure, for- XXV. Hard white rock ....scccseees- waete ie | 0 O merly WOLked. sircecscessnsecestverss O 2 O XXXVI, Hard brown clunch .seccecseveeoreee LO 1 6 TV. Flam Gmpure coal) ...cccccecconseseese O 0 9 DOXSVIT Greaticoalltock’stecsearavercsiec oe I O Westlowchiclocinstenteetsonuhettsessecsecen: (Oje8 SAN MUGS Eletdibind.’ «stsprecetaccarecie 8) 0 0 VI. Brown rock sandstone (No. 1.).....00. 5 0 O DONE Soft DIN Ayes siessenat eowvaseredes is O07 0 Va Clumche sesttesviave Eishsetavertesvraves ive, «0 . OO XXX. Stone measure and Great coal roof VIII. Brown rock sandstone (No. 2.) ...... 38 0 0 (plants abundant)......... secrssesee 2 O O TEXSPLONO I OIN Ae cecteacahoncueseaeshts saekausern Mra 220 nO. XEXI. Great Coal ..rcscccescseresesees aasee tees 110 X. White rock sandstone .......e.000 sees Lu ce a0) XXXII. Three-quarter, Ironstone measure 1 0 6 XG (Glin ChW scewseces ace seen toeeeeste tee. sorrel one One O XXXII. Three-quarter Coal......00 eetessur OF P2mLo XII. Ironstone measures (small concretions XXXIV. Clumper; a hard black bind, with of ironstone) ....000. aRlestecete ons sgsWicr Malem 2? 0; YONSEONE CONCHELIONS oeesevereees aenow LO XIII. Thick cloddy flam, or carbonaceous KXXKV. Smith Coal sirorccsvovccccersesseosese 1 2 O SINGS