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 

 Scodand ; and passed part of three years in examining the geology 

 of Savoy, Switzerland, and France. There is scarcely a rock for- 

 mation 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 collec- 

 tions, 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 dis- 

 coveries 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 Chap- 

 ters are greatly enlarged. 



The following new Chapters have been added . — Chap. II. On 

 Fossil Organic Remains. Chap. IV. On the Principles of Stratifi- 

 cation. Chap. X. A Retrospective View of Geological Facts. 

 Chap. XVin. 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 geo- 

 logical map of England that had then appeared. It presents in one 

 view the grand geological divisions of the country, without delinea- 

 ting 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- 



