Chapter I: Preface: To the Ninth Edition

The Principles of Geology in the first five editions embraced not only a view of the _modern changes_ of the earth and its inhabitants, as set forth in the present work, but also some account of those monuments of analogous changes of _ancient_ date, both in the organic and inorganic world, which it is the business of the geologist to interpret. The subject last mentioned, or "geology proper," constituted originally a fourth book, now omitted, the same having been enlarged into a separate treatise, first published in 1838, in one volume 12mo., and called "The Elements of Geology," afterwards recast in two volumes 12mo. in 1842, and again re-edited under the title of "Manual of Elementary Geology," in one volume 8vo. in 1851. The "Principles" and "Manual" thus divided, occupy, with one exception, to which I shall presently allude, very different ground. The "Principles" treat of such portions of the economy of existing nature, animate and inanimate, as are illustrative of Geology, so as to comprise an investigation of the permanent effects of causes now in action, which may serve as records to after ages of the present condition of the globe and its inhabitants. Such effects are the enduring monuments of the ever-varying state of the physical geography of the globe, the lasting signs of its destruction and renovation, and the memorials of the equally fluctuating condition of the organic world. They may be regarded, in short, as a symbolical language, in which the earth's autobiography is written.

In the "Manual of Elementary Geology," on the other hand, I have treated briefly of the component materials of the earth's crust, their arrangement and relative position, and their organic contents, which, when deciphered by aid of the key supplied by the study of the modern changes above alluded to, reveal to us the annals of a grand succession of past events--a series of revolutions which the solid exterior of the globe, and its living inhabitants, have experienced in times antecedent to the creation of man.

In thus separating the two works, however, I have retained in the "Principles" (book i.) the discussion of some matters which might fairly be regarded as common to both treatises; as for example, an historical sketch of the early progress of geology, followed by a series of preliminary essays to explain the facts and arguments which lead me to believe that the forces now operating upon and beneath the earth's surface may be the same, both in kind and degree, as those which at remote epochs have worked out geological changes. (See Analysis of Contents of this work, p. ix.)

If I am asked whether the "Principles" or the "Manual" should be studied first, I feel much the same difficulty in answering the question as if a student should inquire whether he ought to take up first a treatise on Chemistry, or one on Natural Philosophy, subjects sufficiently distinct, yet inseparably connected. On the whole, while I have endeavored to make each of the two treatises, in their present form, quite independent of the other, I would recommend the reader to study first the modern changes of the earth and its inhabitants as they are discussed in the present volume, proceeding afterwards to the classification and interpretation of the monuments of more remote ages.

CHARLES LYELL.

_11 Harley Street, London_, May 24, 1853.

_Dates of the successive Editions of the "Principles" and "Elements" (or Manual) of Geology, by the Author._

Principles, 1st vol. in octvo, published in Jan. 1830.
----------, 2d vol. do. do. Jan. 1832.
----------, 1st vol. 2d edition in octavo 1832.
----------, 2d vol. 2d edition do. Jan. 1833.
----------, 3d vol. 1st edition do. May, 1833.
----------, New edition (called the 3d) of the whole work
in 4 vols. 12mo May, 1834.
----------, 4th edition, 4 vols. 12mo June, 1835.
----------, 5th do. do. do. Mar. 1837.
Elements, 1st edition in one vol July, 1838.
Principles, 6th do. 3 vols. 12mo June, 1840.
Elements, 2d edition in 2 vols. 12mo July, 1841.
Principles, 7th edition in one vol. 8vo Feb. 1847.
----------, 8th edition in one vol. 8vo May, 1850.
Manual of Elementary Geology (or "Elements," 3d edition)
in one vol. 8vo Jan. 1851.
Manual, 4th edition, one vol. 8vo Jan. 1852.
Principles, 9th edition, now published in one vol. 8vo June, 1853.

ANALYSIS OF THE CONTENTS
OF
THE PRINCIPLES OF GEOLOGY.

BOOK I. (CHAPTERS I. TO XIII.)

HISTORICAL SKETCH OF THE PROGRESS OF GEOLOGY, WITH A SERIES OF
ESSAYS TO SHOW THAT THE MONUMENTS OF THE ANCIENT STATE OF THE
EARTH AND ITS INHABITANTS, WHICH THIS SCIENCE INTERPRETS, CAN
ONLY BE UNDERSTOOD BY A PREVIOUS ACQUAINTANCE WITH TERRESTRIAL
CHANGES NOW IN PROGRESS, BOTH IN THE ORGANIC AND INORGANIC
WORLDS.

CHAPTER I.
Geology defined--Its relation to other Sciences Page 1

CHAPTER II.
Oriental and Egyptian Cosmogonies--Doctrines of the Greeks
and Romans bearing on Geology 4

CHAPTER III.
Historical progress of Geology--Arabian Writers--Italian,
French, German, and English geologists before the 19th
century--Physico-theological school 17

CHAPTER IV.
Werner and Hutton--Modern progress of the science 46

CHAPTER V.
Prepossessions in regard to the duration of past time,
and other causes which have retarded the progress
of Geology 61

CHAPTER VI.
Agreement of the ancient and modern course of nature
considered--Changes of climate 73

CHAPTERS VII. VIII.
Causes of vicissitudes in climate, and their connection
with changes in physical geography 92, 114

CHAPTER IX.
Theory of the progressive development of organic life
at successive periods considered--Modern origin of Man 130

CHAPTER X.
Supposed intensity of aqueous forces at remote
periods--Erratic blocks--Deluges 153

CHAPTER XI.
Supposed former intensity of the igneous forces--Upheaval
of land--Volcanic action 160

CHAPTER XII.
Causes of the difference in texture of older and newer
rocks--Plutonic and Metamorphic action 175

CHAPTER XIII.
Supposed alternate periods of repose and disorder--Opposite
doctrine, which refers geological phenomena to an
uninterrupted series of changes in the organic and inorganic
world, unattended with general catastrophes,
or the development of paroxysmal forces 180

BOOK II. (CHAPTERS XIV. to XXXII.)

OBSERVED CHANGES IN THE INORGANIC WORLD NOW IN PROGRESS: FIRST,
THE EFFECTS OF AQUEOUS CAUSES, SUCH AS RIVERS, SPRINGS,
GLACIERS, WAVES, TIDES, AND CURRENTS; SECONDLY, OF IGNEOUS
CAUSES, OR SUBTERRANEAN HEAT, AS EXHIBITED IN THE VOLCANO AND
THE EARTHQUAKE.

CHAPTER XIV.
Aqueous causes--Excavating and transporting power of rivers 198

CHAPTER XV.
Carrying power of river-ice--Glaciers and Icebergs 219

CHAPTER XVI.
Phenomena of springs 232

CHAPTER XVII.
Reproductive effects of rivers--Deltas of lakes and inland
seas 251

CHAPTER XVIII.
Deltas of the Mississippi, Ganges, and other rivers exposed
to tidal action 263

CHAPTERS XIX. XX. XXI.
Denuding, transporting, and depositing agency of the waves,
tides, and currents--Waste of sea-cliffs on the coast
of England--Delta of the Rhine--Deposition of sediment
under the influence of marine currents 290, 321, 337

CHAPTER XXII.
Observed effects of igneous causes--Regions of active
volcanoes 344

CHAPTERS XXIII. XXIV.
History of the volcanic eruptions of the district round
Naples--Structure of Vesuvius--Herculaneum and Pompeii 360, 375

CHAPTER XXV.
Etna--Its eruptions--Structure and antiquity of the cone 396

CHAPTER XXVI.
Volcanoes of Iceland, Mexico, the Canaries, and Grecian
Archipelago--Mud volcanoes 424

CHAPTER XXVII.
Earthquakes and the permanent changes attending them 451

CHAPTER XXVIII.
Earthquake of 1783 in Calabria 471

CHAPTER XXIX.
Elevation and subsidence of dry land, and of the bed of
the sea during earthquakes--Evidence of the same afforded
by the Temple of Serapis near Naples 493

CHAPTER XXX.
Elevation and subsidence of land in regions free from
volcanoes and earthquakes--Rising of land in Sweden 519

CHAPTERS XXXI. XXXII.
Causes of earthquakes and volcanoes--Theory of central
fluidity of the earth--Chemical theory of volcanoes--Causes
of permanent upheaval and depression of land 533, 545

BOOK III. (CHAPTERS XXXIII to L.)

OBSERVED CHANGES OF THE ORGANIC WORLD NOW IN PROGRESS; FIRST,
NATURE AND GEOGRAPHICAL DISTRIBUTION OF SPECIES, AND THEORIES
RESPECTING THEIR CREATION AND EXTINCTION; SECONDLY, THE
INFLUENCE OF ORGANIC BEINGS IN MODIFYING PHYSICAL GEOGRAPHY;
THIRDLY, THE LAWS ACCORDING TO WHICH THEY ARE IMBEDDED IN
VOLCANIC, FRESHWATER, AND MARINE DEPOSITS.

CHAPTERS XXXIII. XXXIV. XXXV. XXXVI.
Whether species have a real existence in nature--Theory
of transmutation of species--Variability of
species--Phenomena of hybrids in animals and
plants 566, 578, 591, 600

CHAPTER XXXVII.
Laws which regulate the geographical distribution of
species--Distinct provinces of peculiar species of
plants--Their mode of diffusion 612

CHAPTER XXXVIII.
Distinct provinces of peculiar species of
animals--Distribution and dispersion of
quadrupeds, birds, and reptiles 629

CHAPTER XXXIX.
Geographical distribution and migrations
of fish--Of testacea--Of zoophytes--Of
insects--Geographical distribution and
diffusion of the human race 646

CHAPTER XL.
Theories respecting the original introduction of
species--Reciprocal influence of species on each other 665

CHAPTERS XLI. XLII.
Extinction of species--How every extension of the range
of a species alters the condition of many others--Effect
of changes of climate 677, 689

CHAPTER XLIII.
Creation of species--Whether the loss of certain animals
and plants is compensated by the introduction of
new species 701

CHAPTER XLIV.
Modifications in physical geography caused by organic beings 708

CHAPTER XLV.
Imbedding of organic remains in peat, blown sand,
and volcanic ejections 718

CHAPTER XLVI.
Imbedding of the same in alluvial deposits and in caves 730

CHAPTER XLVII.
Imbedding of organic remains in aqueous deposits--Terrestrial
plants--Insects, reptiles, birds, quadrupeds 742

CHAPTER XLVIII.
Imbedding of the remains of man and his works 753

CHAPTER XLIX.
Imbedding of aquatic animals and plants, both freshwater
and marine, in aqueous deposits 765

CHAPTER L.
Formation of coral reefs 775

LIST OF PLATES.

DIRECTIONS TO THE BINDER.

FRONTISPIECE, View of the Temple of Serapis
at Puzzuoli in 1836, _to face_ title page.

PLATE 1. Map showing the Area in Europe which
has been covered by Water since the
beginning of the Eocene Period _to face_ p. 121

2. Boulders drifted by Ice on the Shores
of the St. Lawrence 220

3. View looking up the Val del Bove, Etna 403

4. View of the Val del Bove, Etna, as seen from above 404

PRINCIPLES OF GEOLOGY.