Produced by Julia Miller, Iris Schroeder-Gehring and the Online Distributed Proofreading Team at http://www.pgdp.net (This file was produced from images generously made available by The Internet Archive/American Libraries.) [Illustration: From a Painting by James Hall, Esq. Engraved by S. Williams. STRATA OF RED SANDSTONE, SLIGHTLY INCLINED, RESTING ON VERTICAL SCHIST, AT THE SICCAR POINT, BERWICKSHIRE. TO ILLUSTRATE UNCONFORMABLE STRATIFICATION. See page 60. _"The mind seemed to grow giddy by looking so far into the abyss of time; and while we listened with earnestness and admiration to the philosopher who was now unfolding to us the order and series of these wonderful events, we became sensible how much farther reason may sometimes go than imagination can venture to follow."_--PLAYFAIR, Biography of Hutton.] A MANUAL OF ELEMENTARY GEOLOGY: OR, THE ANCIENT CHANGES OF THE EARTH AND ITS INHABITANTS AS ILLUSTRATED BY GEOLOGICAL MONUMENTS. BY SIR CHARLES LYELL, M.A. F.R.S. AUTHOR OF "PRINCIPLES OF GEOLOGY," "TRAVELS IN NORTH AMERICA," "A SECOND VISIT TO THE UNITED STATES," ETC. ETC. "It is a philosophy which never rests--its law is progress: a point which yesterday was invisible is its goal to-day, and will be its starting post to-morrow." EDINBURGH REVIEW, No. 132. p. 83. July, 1837. _FOURTH AND ENTIRELY REVISED EDITION._ ILLUSTRATED WITH 500 WOODCUTS. LONDON: JOHN MURRAY, ALBEMARLE STREET. 1852. LONDON: SPOTTISWOODES and SHAW, New-street-Square. PREFACE TO THE FOURTH EDITION. In consequence of the rapid sale of the third edition of the "Manual," of which 2000 copies were printed in January last, a new edition has been called for in less than a twelvemonth. Even in this short interval some new facts of unusual importance in palaeontology have come to light, or have been verified for the first time. Instead of introducing these new discoveries into the body of the work, which would render them inaccessible to the purchasers of the former edition, I have given them in a postscript to this Preface (printed and sold separately), and have pointed out at the same time their bearing on certain questions of the highest theoretical interest.[v-A]