PREFACE TO THE THIRD EDITION. 



Vil 



logical map of England and Wales. This map, from the great va- 

 riety of its useful details, and its general correctness, may be re- 

 garded 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, with- 

 out 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 ob- 

 scure : 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, 1 would claim the 

 candid indulgence of the reader, in the last words of that distin- 

 guished geologist, Horace Benedict de Saussure, " On pent etre 

 utile, sans aiteindre a la 'perfection.''^ 



