SOCIETY. J TRANSACTIONS OF THE GEOLOGICAL SOCIETY, ESTABLISHED NOVEMBER 13, 1807. VOLUME THE FOURTH. -Quod si cui mortalium cprdi et curae sit, non tantum inventis haerere, atque iis uti, sed ad ulteriora penetrare; atque non disputando adversarium, sed opere naturam vincere; denique non belle et probabiliter opinari, sed certo et ostensive scire; tales, tanquam veri scientarum filii, nobis (si videbitur) se adjungant. Novum Organum, Prcefatio. LONDON: PRINTED AND SOLD XT WILLIAM PHILLIPS, GEORGE YARD, LOMBARD STREET. 1817. OFFICERS AND COUNCIL OF THE GEOLOGICAL SOCIETY, ELECTED FEBRUARY 7, 1817. PRESIDENT, JOHN MAC CULLOCH, M.D. F.L.S. VICE - PRESIDENTS, The Hon. HENRY GREY BENNET, M.P. F.R.S. The Right Hon. Sir JOHN NICHOLL, MP. F.R.S. WILLIAM BLAKE, Esq. F.R.S. HENRY WARBURTON, Esq. F.R.S. SECRETARIES, CHARLES STOKES, E«q. F.A. & L.S. J HENRY JAMES BROOKE, Esq. FOREIGN SECRETARY, AUGUSTUS BOZZI GRANVILLE, M.D. F.L.S. TREASURERS, DANIEL MOORE, Eiq. F.R.A. & L.S. j JOHN TAYLOR, Esq. COUNCIL, ARTHUR AIKIN, Esq. HENRY HOLLAND, M.D. F.R.S. THOMAS COLBY, Esq, Captain of the Royal ASHHURST MAJENDIE, Esq. Engineers. WILLIAM HASLEDINE PEPYS, Esq. F..R.S. HENRY THOMAS COLEBROOKE, Esq. F.R.S EDMOND WALLER RUNDELL, Esq. Sir HENRY CHARLES ENGLEFIELD, Bart. F.R A. & R.S. Ed. & A.P. Newc. M.R. Inst. SAMUEL SOLLY, Esq. F.R.S. GEORGE BELLAS GREENOUGH, Esq. JOHN WHISHAW, Esq. F.R.S. F.R. & L.S. WILLIAM HYDE WOLLASTON, M.D. F.R.S. KEEPER OF THE MUSEUM AND DRAUGHTSMAN, Mr. THOMAS WEBSTER. TRUSTEES OF THE GEOLOGICAL SOCIETY, GEORGE BELLAS GREENOUGH, Esq. Sir ABRAHAM HUME, Bart. M.P. WILLIAM BABINGTON, M.D. ROBERT FERGUSON, Eeq. DAVID RICARDO, Esq. SAMUEL WOODS, Esq. ADVERTISEMENT. THE Editors of the Transactions of the Geological Society are directed to make it known to the Public, that the Authors alone are responsible for the facts and opinions contained in their respective papers. Geological Society, July I, 1817. It is requested that all letters and communications to the Secretaries, and presents to the Society, be addressed to the House of the Geological Society, No. 20, Bedford Street, Covent Garden, London. GEOLOGICAL, SOCIETY, j PLATES AND MAPS IN ILLUSTRATION OF THE FOURTH VOLUME OF THE GEOLOGICAL SOCIETY. LONDON: I'XfNTED JlfD SOLD 11Y WltLlAM PHILLIPS, GEORGK VAltV^ LOMBAUB STUKKT. 1817..