VI 



PREFACE TO THE TENTH EDITION. 



Principles, 7th edition, in 1 vol. 8vo. published in 



8th edition 



M 



79 



Elements, 3d edition (or Manual of Elementary Geology), in 



1 vol. 8vo 



Elements, 4th edition (or Manual) in 1 vol. 8vo. 



Principles, 9th edition, published in 1 vol. 8vo. 

 Antiquity of Man, 1st, 2nd, and 3rd editions 

 Elements, 6th edition, in 1 vol. 8vo. 



Feb. 1847. 

 May 1850. 



Jan. 1851. 



. Jan. 1852. 



. June 1853. 



Feb.— Nov. 1863. 



. Jan. 1865. 



Principles; 10th edition, in 2 vols, 8vo., the first now published. Nov. 1866. 



The ' Principles of Geology/ in the first five editions, em- 

 braced not only a view of the modem changes of the earth and 

 its inhabitants, but also some account of those monuments of 



analogous changes of ancient date, both in the organic and 



inorganic world, which the geologist is called upon to inter- 



i 



pret. 



The subject last mentioned, or ' geology proper 



omitted 



having been enlarged into a separate treatise, first published 



mo 



GeoloPT,' afterwards recast in two volumes 12mo. in 1842. 

 again re-edited under the title of ' Manual of Elementary 

 Geology/ in one volume 8vo. in 1851, and lastly under the 

 title of c Elements of Geology/ in one volume 8vo. in 1865. 



The ' Principles ' and ' Elements/ 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 geo- 

 graphy 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 auto- 

 biography is written. 



In the ' Elements of Geology,' on the other hand, I have 











