TRANSACTIONS OF THE GEOLOGICAL SOCIETY OF LONDON. SECOND SERIES. VOLUME III. PART THE FIRST. Quod si cui mortalium cordi et curse 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 scientiarum filii, nobis (si videbitur) se adjungant. Novum Organum, Prcefatio. LONDON: PRINTED BY RICHARD TAYLOR, RED LION COURT, FLEET STREET. SOLD AT THE APARTMENTS OF THE GEOLOGICAL SOCIETY, SOMERSET HOUSE. 1829. OFFICERS AND COUNCIL OF THE GEOLOGICAL SOCIETY OF LONDON. 1829. PRESIDENT. Rev. ADAM SEDGWICK, M.A. F.R.S. Woodwardian Professor in the University of Cambridge. VICE-PRESIDENTS. Rev. WILLIAM BUCKLAND, D.D. F.R.S. & LEONARD HORNER, Esq. F. R.S. Warden of the F.L.S. Professor of Mineralogy and Geology in the University of London. University of Oxford. HENRY WARBURTON, Esq. M.P. F.R.S. F.L.S. GEORGE BELLAS GREENOUGH, Esq. F.R.S. & F.H.S. F.L.S. & F.H.S. SECRETARIES. WILLIAM JOHN BRODERIP,Esq. F.R.S. F.L.S. I RODERICK IMPEY MURCHISON, Esq. F.R.S. & F.H.S. & F.L.S. FOREIGN SECRETARY. CHARLES LYELL, Esq. M.A. F.R.S. & F.L.S. TREASURER. JOHN TAYLOR, Esq. F.R.S. & F.H.S. COUNCIL. ARTHUR AIKIN, Esq. F.L.S. Secretary to the DA VIES GILBERT, Esq. M.P. M.A. President Society of Arts, &c. of the Royal Society, F.S.A. F.L.S. & F.H.S. JAMES EBENEZER BICHENO, Esq. F.R.S. JOHN LINDLEY, Esq. F.R.S. & F.L.S. Sec. L.S. Rev. JOHN HONEYWOOD RANDOLPH, M.A. JOHN BOSTOCK, M.D. F.R.S. F.L.S. & F.H.S. PETER MARK ROGET, M.D. Sec.R.S. F.L.S. DECIMUS BURTON, Esq. F.S.A. M.R. I. A. GEORGE EVEREST, Esq. Captain in the Hon. NICHOLAS AYLWARD VIGORS, Esq. M.A. E. I. C. S. F.R.S. Superintendent of .he Great F.R.S. Sec. Zool. Soc. M.R.I.A. F.S.A. F.L.S. Trigonometrical Survey cf India. & F.K.S. MICHAEL FARADAY, Esq. F.R.S. Cor. Mem. NATHANIEL WALLICH, M.D. F.L.S. of the Academy of Sciences at Paris. M.R. I. A. Rev. JAMES YATES, M.A. F.L.S. WILLIAM HENRY FITTON, M.D. F.R.S. & F.L.S. CURATOR AND LIBRARIAN. WILLIAM LONSDALE, 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 respon­ sible for the facts and opinions contained in their respective papers. It is requested that all letters and communications to the Secretaries, and presents to the Society, may be addressed to the Apartments of the Geological Society, Somerset House, London. .