BOOK II. 



FOSSILS. 



If, in ending this sketch of geology, we now inquire 

 from what sources the learned have been able to decipher 

 the dark phases through which earth has passed, we see 

 that they have managed to extract most valuable data from 

 the numerous vestiges of creatures which successively peo- 

 pled it, and which are found scattered on its surface or in 

 its deep layers. 



In fact, the fossiliferous rocks only represent the cata- 

 combs of the former creations, miraculously preserved 

 through ages, and the ineffaceable impressions which they 

 have left in every terrestrial stratum seem like so many 

 medals destined to mark the various revolutions of the 

 globe. 



The different layers of our sphere have faithfully be- 

 queathed to us vestiges of all that once animated their sur- 

 face ; nothing has been lost in this great medal-cabinet of 

 nature. The Dragon-Fly, with its wings of gauze, is quite 

 as well preserved as the ponderous skeleton of the mastodon. 

 The carapace of a microscopic infusorial animal lies by the 

 side of the bony case of a gigantic tortoise. Some of the 

 flowers which perfumed the first meadows on the globe 



