The Third Edition of this work was re-published in America, in 1829, by Professor Silliman of Yale College, Connecticut, the distinguished Editor of the American Journal of Science. It was commenced without any previous communication or acquaintance with the author. The reasons for the re-publication were stated in the Professor's preface, an extract from which is subjoined. The author will be satisfied if the present work should be thought deserving of the commendation given by the American editor, of being "a comprehensive Treatise on Geology, which the student will be willing to read, and able to understand."

Hampstead, near London,
April 18, 1833.

Part of Professor Silliman's Preface of the American re-print of the Third Edition.

The Editor believes that he is performing a service to his country, by encouraging the re-publication of a work conspicuous for attractiveness, for perspicuity, for a style generally vigorous and correct, often eloquent and beautiful; and for an independence of spirit, which carries the Author straight forward to his object, certainly without any servile regard to previous systems. While bestowing this merited commendation, we do not mean to say that we fully adopt all the Author's theoretical views, although most of them appear to be philosophical and just, and some of them are peculiarly happy.

Speaking in the character of a public instructor of youth, I beg leave to add, that my immediate motive for recommending the republication was, that I might place in the hands of my own classes, a comprehensive treatise on geology, which they would be willing to read and able to understand.

CAUTION.-In 1829, a book was published in duodecimo, entitled "An Introduction to the study of Mineralogy, by J. R. Bakewell." Several friends of the Author of the present volume have informed him, that they were induced, by the name, to purchase the book; he therefore thinks it necessary to state, that he has no connection with the writer of that book, and he has reason to believe that the name was assumed to mislead the public.

PREFACE TO THE THIRD EDITION.

THE First and Second Editions of the Introduction to Geology were favourably received, and sold off, soon after their publication. The work has since been translated and published in Germany, by Mr. Frederick Muller of Friburg; but it has been long out of print in this country. The causes which have retarded the publication of a Third Edition it is unnecessary to mention: the delay has, I trust, been favourable to its appearance in a very improved state; as I have been collecting materials for it, during several years, having visited almost every situation of much geological interest in our own island, from the Land's End in Cornwall, to the Grampian Mountains in Scotland; and passed part of three years in examining the geology of Savoy, Switzerland, and France. There is scarcely a rock formation described in the present volume, that I have not examined in its native situation, and compared with the descriptions of former geologists. I have also had opportunities of examining the collections, and of profiting by the communications, of some of the most eminent geologists on the Continent.

While engaged in these pursuits, I have not been inattentive to the labours of other observers. So numerous and interesting are the discoveries made in geology during the last ten years, that in order to present a concise view of the science in its present advanced state, the Introduction to Geology has been recomposed, and all the Chapters are greatly enlarged.

The following new Chapters have been added.-Chap. II. On Fossil Organic Remains. Chap. IV. On the Principles of Stratification. Chap. X. A Retrospective View of Geological Facts. Chap. XVIII. On the Destruction of Mountains; and on the Bones of Land Quadrupeds, found in Diluvial Depositions and in Caverns. Chap. XIX. On the Formation of Valleys; and on Deluges and Denudations.-The Plates are new, except Plate IV. and part of Plate VII.

The Outline Map of the Geology of England and Wales, was I believe, when published in the First Edition of 1813, the only geological map of England that had then appeared. It presents in one view the grand geological divisions of the country, without delineating the different strata in each division. Mr. William Smith has since published a map of the Geology of England, which possesses extraordinary merit,-when it is considered as the unaided attempt of one person, to trace the course of each rock formation through England and Wales. Mr. Greenough, and other members of the Geological Society of London, have subsequently published a geo

logical map of England and Wales. This map, from the great variety of its useful details, and its general correctness, may be regarded as the best approximation to a complete exhibition of the geology of an extensive country, that has yet appeared. It was thought, however, that the publication of my Map in its original form, (or nearly so,) would be acceptable to those who wished to gain a general knowledge of the geology of their own country, without entering into geological details; and that it would also serve as a useful introduction to the study of the above mentioned maps.

In the course of the present work, I have frequently attempted to elucidate the geology of England, by comparisons with situations I have examined on the Continent, in order to connect the geology of our own island, with that of France, Switzerland, and Savoy.

By comprising the numerous facts and observations contained in the present volume, within the limits of an elementary work, from the desire to be concise, I may have run the risk of becoming obscure this I have studiously endeavored to avoid; my chief aim being to present the reader with a system of Geology, which shall describe and explain geological phenomena in a clear and intelligible manner, and as free from. technical obscurity as the nature of the subject would admit. In order that the price may not exceed that of the last Edition, this work is printed in a smaller type. For any errors into which I may have inadvertently fallen, I would claim the candid indulgence of the reader, in the last words of that distinguished geologist, Horace Benedict de Saussure, "On peut être utile, sans atteindre à la perfection."

PREFACES TO THE FIRST AND SECOND EDITIONS,

ABRIDGED.

In tracing the progress of knowledge, we may frequently observe that the cultivation of particular branches of science, at certain periods, was determined by causes which had little connection with their intrinsic utility. Fashion, caprice, and the authority of eminent names, govern mankind in philosophy, as well as on all other subjects. But, independently of accidental causes, there are leading objects in the universe, which, as nations advance in civilization, seem naturally to direct their attention to certain sciences in succession. The brilliancy of the sun, moon, and planets, their various motions, and connection with the changing seasons, would first arrest the attention of the rude philosopher; nor need we wonder that he soon began to regard them as endowed with life and intelligence, and attributed to them a mysterious power over human affairs: thus the heavenly orbs became the objects of religious adoration; and curiosity, hope, and fear, lent their aid to the early cultivation of astronomy.

Mathematics and mechanical philosophy are so intimately connected with astronomy and the most useful arts, that they naturally claimed the second place among the early sciences.

The branches of philosophy which comprise a knowledge of the physical qualities of matter, or such as are perceptible by the senses, follow next; and at a later period, chemical philosophy, or that science which endeavours to ascertain the elementary substances, of which all material objects are composed. In the order of succession, mineralogy and geology are the last of the natural sciences; for though an acquaintance with the earth is more important to man, than a knowledge of the distant parts of the universe, yet, previously to the cultivation of the other sciences, and of chemistry in particular, our knowledge of the mineral kingdom could not extend much beyond that of the rudest periods. Thus we find, that notwithstanding the precious metals, and many of the mineral treasures which the earth contains, have been the objects of insatiable cupidity in every age, yet, till the present day, almost all that was known of mineralogy was confined to uneducated working miners.

In looking over the pages of history we may observe, that the most polished nations of antiquity had scarcely advanced beyond a limited acquaintance with astronomy, geometry, and mechanical philosophy. In modern Europe, all the natural sciences, geology and mineralogy excepted, have been successfully cultivated, and their progress has been astonishingly rapid; but till about the middle of the last century, the structure of the earth had scarcely engaged the attention of philosophers. Near that time, Lehman, the German, first observed that there are certain rocks which occupy the lowest relative situation in different countries, and that these rocks contain no organic remains: hence he gave them the name of primary, and established a division between them and the rocks by which they are

covered, in which the remains of animals or vegetables frequently occur the latter he called secondary. In our own country, the Reverend J. Michell was the first person who appears to have had any clear views respecting the structure of the external parts of the earth: they were made public in a valuable paper on the cause of earthquakes, in the Philosopical Transactions, 1759. About twenty years afterwards, Mr. John Whitehurst published his "Inquiry into the original State and Formation of the Earth." His observations were principally confined to the rocks and strata of Derbyshire. Independently of its speculative opinions, this work was highly valuable as an attempt to describe the geology of a district, from actual examination. The great variety of original information it contained, and its general accuracy, will remain a lasting monument of the writer's industry and ability. Mr. Whitehurst, however, fell into the same error with the celebrated Werner in Saxony, an error to which the first cultivators of geology were particularly exposed, that of drawing general conclusions from local observations, and forming universal theories from a limited number of facts.

Though Mr. Whitehurst's book was favourably received, yet till the beginning of the present century geological pursuits made little progress in England. On the continent, the researches of Saussure, Pallas, Werner, St. Fond, Dolomieu, and others, had before this time produced a powerful interest, and brought into the field many active and enlighted enquirers. The first general impulse given to the public taste, for geological investigations in this country, was produced by Professor Playfair's luminous and eloquent illustrations of the Huttonian theory. The leading feature of this theory, that all rocks or strata have been either formed or consolidated by central subterranean fire, was very warmly opposed; and much personal animosity and many adventitious circumstances were associated with the contest, not highly honourable to philosophy, but well calculated to keep alive the attention of the disputants to those appearances in nature which favoured or opposed their different theories.

He who attempts to make a scientific subject familiar, runs the risk, in this country, of being deemed superficial; a plentiful share of dullness, combined with a certain degree of technical precision, are regarded as essential proofs of profundity. By prescriptive right, long established in these realms, dullness and pedantry guard the portals of the temple of Science, and command those who enter, to avert their eyes from whatever can elevate the imagination, or warm the heart, and to look at nature through a sheet of ice. In compliance with their authority, writers of introductory treatises have generally thought it necessary to avoid that felicity in the familiar illustration of scientific subjects, so conspicuous in some elementary works of our neighbours. Without venturing to depart too far from established usage, I have endeavoured to render geology more intelligible, by avoiding as much as possible theoretical and technical language, and by introducing a simple arrangement, and suited to the present state of our knowledge. The local illustrations from

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