OF CREATION. 



271 



but, afterwards, when the land had risen above the 

 sea in various places, and yielded different kinds of 

 detritus, the water in some places was nearly fresh, in 

 others brackish, and in others, again, perfectly salt. 

 In this way all varieties of development are accounted 

 for; and we may understand how the coarse and 

 occasionally flinty limestone found at Paris, the great 

 and uniform mass of clay near London, the marly 

 clay of Brussels, the highly siliceous material, pro- 

 bably deposited from warm springs, in central France, 

 and the limestones of the Greek Archipelago and 

 Asia Minor, all present fossils having something of 

 the same general character, and belonging to the 

 same epoch. In the tertiary beds in western Europe, 

 there is, on the whole, not much distinct uniformity 

 of character ; but when we examine the contempo- 

 raneous deposits of northern India and South Ame- 

 rica, we find evidence of the operations of nature 

 having been conducted on as grand a scale during the 

 tertiary as during the preceding geological epochs. 



The beds of London clay at Sheppey and else- 

 where are not only remarkable for the amount of 

 information they give us concerning the vegetation of 

 the early tertiary period in Europe, but are almost 

 equally instructive with regard to the animal inha- 

 bitants of the land at that time. 



A considerable number of shells are found, both 

 univalve and bivalve, of which the annexed figures 

 (114 117) will give some idea, but the most re- 

 markable fact concerning them is the absence of the 

 whole group of ammonites, and their replacement by 

 a newly-introduced genus of carnivorous tracheli- 

 pods (animals of lower organization), which here 



