some of the most eminent geologists on the Conti

nent.

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. 11. 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. Wm. 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 geological map of England and Wales. This map, from the great variety of its useful details, and its general correctness, may be regarded as the most 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 endeavoured to avoid; my chief aim being to present the reader with a system of Geology, which shall 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."

1 shall conclude with some observations on the means of advancing geological knowledge. In a conversation I had with that experienced geologist Professor Brochant at Paris, on this subject,-he said: "We are already sufficiently rich in facts, what is now wanting, is an accurate review of these facts: many geological descriptions, on which much stress continues to be laid, were written in an early state of the science, and require such corrections, as a comprehensive view of recent discoveries could scarcely fail to suggest.—I should recommend, Sir, that two active young men, competently instructed, should be sent out to examine all the most remarkable situations described by former geologists, and to note down their observations on the spot. They should travel together, not only for the sake of mutual comfort and assistance, in the solitary situations they might have to visit, but in the examination of dubious phenomena, that the observations of the one might correct or confirm those of the other.” -These remarks of M. Brochant, which I have given as correctly as my memory and the difference

of language would allow, well deserve the attention of all Geological Societies*.

What appears to me much wanted to clear up several dubious points in Geology, is a series of experiments, to ascertain the relative position and connection of certain rocks. This in some instances might be effected, by employing workmen to open out the edges of strata: other cases would require shafts to be sunk, and passages to be driven into the sides of mountains. Such experiments would be attended with expense; but they would reward us by the discovery of important facts, which must otherwise remain for ever unknown.

*A Geological Map of France is at present in progress, under the direction of Professor Brochant.

HAMPSTEAD, near LONDON,

March 10, 1828.

1

PREFACES

ΤΟ

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.