356 BUFFALO LAND. 



gle bones of the paddlo were eight inches long, giving 

 the Bpread of the expanded flippers as considerably 



over twenty feet. But the ribs were those of an 

 ordinary turtle just born, and the great plates repre 

 sented the bony deposit in the skin, which, com 

 mencing independently in modern turtles, united 

 with the expanded ribs below, at an early day. But 

 it was incredible that the largest of known turtles 

 should be but just hatched, and for this and other 

 reasons it has been concluded that this " ancient mari- 

 ner" is one of those forms not uncommon in old days, 

 whose incompleteness in some respects points to the 

 truth of the belief, that animals have assumed their 

 modern perfection, by a process of growth from more 

 simple beginnings. 



The cretaceous ocean of the West was no less re- 

 markable for its fishes than for its reptiles. Sharks 

 do not seem to have been so common as in the old 

 Atlantic, but it swarmed with large predaceous forms 

 related to the salmon and saury. 



Vertebra) and other fragments of these species pro- 

 ject from the worn limestone in many places. I will 

 call attention to, perhaps, the most formidable, as 

 well as the most abundant of these. It is the one 

 whose bones most frequently crowned knobs of shale, 

 which had been left standing amid surrounding de- 

 struction. The density and hardness of the bones 

 shed the rain off on either side, so that the radiating 

 gutters and ravines finally isolated the rock mass 

 from that surrounding. The head was some inches 

 longer than that of a fully grown grizzly bear, and 

 the jaws were deeper in proportion to their length. 



