STRATA OF RED SANDSTONE, SLIGHTLY INCLINED. RESTING ON VERTICAL SCHIST, AT THE SICCAR POINT, BERWICKSHIRE. To ILLUSIRATE UNCONFORA A3LE 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. 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. PRESIDENT OF THE GEOLOGICAL SOCIETY OF LONDON ; 66 AUTHOR OF PRINCIPLES OF GEOLOGY," "TRAVELS IN NORTH AMERICA," ETC. ETC. "It is a philosophy which never rests its law is progress: a point which yesterday EDINBURGH REVIEW, No. 132. p. 83. July 1837. THIRD AND ENTIRELY REVISED EDITION. Ellustrated with more than Five hundred Woodcuts. LONDON: JOHN MURRAY, ALBEMARLE STREET. HARVARD COLLEGE LIBRARY LONDON: SPOTTISWOODES and SHAW, New-street-Square. PR.E FACE. THIS treatise is not an epitome of the "Principles of Geology," nor intended as introductory to that work. I find it necessary to state this at once, and to explain the different ground occupied by the two publications, because much confusion has arisen on the subject. The first five editions of the "Principles" comprised a 4th book, in which some account was given of systematic geology, and in which the principal rocks composing the earth's crust and their organic remains were described. In subsequent editions this book was omitted, it having been expanded, in 1838, into a separate treatise called the "Elements of Geology," first re-edited in 1842 and now again recast and enlarged. Although the subjects of both treatises relate to geology, as their titles imply, their scope is very different, the "Principles " containing a view of the modern changes of the earth and its inhabitants, while the "Manual" relates to the monuments of ancient changes. In separating the one from the other, I have endeavoured to render each complete in itself, and independent; but if asked by a student which he should read first, I would recommend him to begin with the "Principles," as he may then proceed from the known to the unknown, and be provided beforehand with a key for interpreting the ancient phenomena whether of the organic or inorganic world, by reference to changes now in progress. Owing to the former incorporation of the two subjects in one work, and the supposed identity of their subject matter, it may be useful to give here a brief abstract of the contents of the Principles," for the sake of comparison. 66 Abstract of the "Principles of Geology," Eighth Edition. BOOK I. 1. Historical sketch of the early progress of geology, chaps. i. to iv. 2. Circumstances which combined to make the first cultivators of the science regard the former course of nature as different from the |