OF CREATION. 189 



but, on the other hand, a very unusual proportion of 

 fishes, of crustaceans of various kinds, and of insects, 

 often in the most singular state of preservation. 

 From these as well as from other remains of in- 

 sects and crustaceans of the same period, character- 

 istic forms of which are given in the accompanying 

 wood-cuts (68, 69), we may deduce the fact that 

 there was but little difference in general form, pro- 

 portions, or structure between the ancient inhabitants 

 of the sea-coast and the existing ones, so far as such 

 groups are concerned, and that there is nothing in 

 them to indicate a warmer climate, or any peculiarity 

 in the condition of the atmosphere. 



Among the shells most common during the oolitic 

 period there are many whose resemb- Fig. 70 

 lance to existing species is also strik- 

 ing, and which certainly point to a 

 very different condition having then 

 obtained ; but the genus Terebratula 

 seems to have been far more pre- 

 dominant than it now is, and in Some TEREBRATULA. 

 localities particular species of these gregarious animals 

 existed in beds at the bottom of the sea, almost 

 to the exclusion of other animals. 



The tribes of bivalve and also of univalve mol- 

 luscs were, however, amply represented during this 

 period, and every day is adding to the number of 

 species, and the variety of generic forms assumed by 

 these creatures. From the careful study of these 

 on the spot, much light will probably hereafter be 

 thrown on the condition and depth of the sea and the 

 movements of the sea bottom during the part of the 

 period of which certain groups are characteristic. 



