THEORY OF THE EARTH. 239 



only, how should iron have been so little known 

 in the times of remote antiquity ? 



General Conclusion relative to the Period of the last 

 Revolution. 



I agree, therefore, with MM. Deluc and Do- 

 lomieu, in thinking, that if any thing in geology 

 be established, it is, that the surface of our globe 

 has undergone a great and sudden revolution, 

 the date of which cannot be referred to a much 

 earlier period than five or six thousand years ago ; 

 that this revolution overwhelmed and caused to 

 disappear the countries which were previously in- 

 habited by man, and the species of animals now 

 best known ; that, on the other hand, it laid dry 

 the bottom of the last sea, and formed of it the 

 countries which are at the present day inhabited ; 

 that it is since the occurrence of this revolution 

 that the small number of individuals dispersed by 

 it have spread and propagated over the newly ex- 

 posed lands, and, consequently, that it is since 

 this epoch only, that human societies have assu- 

 med a progressive march, that they have formed 

 establishments, raised monuments, collected natu- 

 ral facts, and invented scientific systems. 



But the countries which are at present inhabi- 

 ted, and which the last revolution laid dry, had 

 already been previously inhabited, if not by men, 



