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V.I

PRINCIPLES OF GEOLOGY - !

OR THE

MODERN CHANGES OF THE EARTH

AND ITS INHABITANTS

CONSIDERED AS ILLUSTRATIVE OF GEOLOGY

BY SIR CHARLES LYELL, BART., M.A., F.R.S.

'Verè scire est per causas scire'-BACON

The stony rocks are not primeval, but the daughters of Time'-LINNÆUS, Syst. Nat.
ed. 5, Stockholm, 1748, p. 219

Amid all the revolutions of the globe the economy of Nature has been uniform, and
her laws are the only things that have resisted the general movement. The rivers and
the rocks, the seas and the continents, have been changed in all their parts; but the
laws which direct those changes, and the rules to which they are subject, have re-
mained invariably the same'-PLAYFAIR, Illustrations of the Huttonian Theory, § 374

ELEVENTH AND ENTIRELY REVISED EDITION

IN TWO VOLUMES-VOL. I.

Illustrated with Maps, Plates, and Woodcuts

LONDON

JOHN MURRAY, ALBEMARLE STREET

1872

The right of translation is reserved

LONDON: PRINTED BY

SPOTTISWOODE AND CO., NEW-STREET SQUARK AND PARLIAMENT STREET

PREFACE

ΤΟ

THE ELEVENTH EDITION.

THERE has been an interval of five years between the last and present edition of this first volume of the 'Principles of Geology.' During this time much discussion has taken place on important theoretical points bearing on meteorology and climate, and much new information obtained by deep-sea dredging in regard to the temperature, and shape, of the bed of the ocean, and its living inhabitants.

In order to avail myself of this newly acquired knowledge, I have found it necessary to recast Chapters X., XI., XII., and XIII., which relate to the geological proofs of former changes of climate, and the paramount importance of the distribution and height of the land over all other causes in bringing about past variations of temperature. At the same time I have endeavoured to render more intelligible some of those astronomical changes which must periodically affect climate, though probably not in so influential a degree as some have imagined.

In Chapter XX. I have briefly dwelt upon the latest known facts concerning marine currents, especially those in the Straits of Gibraltar, and have considered some

theories of oceanic circulation recently propounded to account for the cold of the abysses of the ocean. With these exceptions, the work has been reprinted mainly as it stood in 1867, with corrections and additions.

The changes made in the tenth edition were so numerous and important that I have thought it best to reprint the Preface to that edition in full, thereby giving the reader the opportunity of knowing what advance has been made in the work since 1853 when the ninth edition appeared. The pages of additions and corrections given in that preface correspond so nearly to those of the present volume that the passages referred to may be always found by turning a few pages backwards or forwards.

73 HARLEY STREET:
January 15, 1872.

CHARLES LYELL.