129 



importance during the Niobrara epoch of the Cretaceous period. This is 

 indicated by the great profusion of individual remains and specific forms. 

 Although occurring in America, wherever the Cretaceous formation appears, 

 they are, so far, more numerously represented in Kansas than elsewhere. 

 Though not rare in New Jersey, crocodiles and tortoises outnumber them ; 

 but, in Kansas, all other orders are subordinate to the Pythommorpha. As is 

 now well known, since 1868,' the seas of the American continent were the 

 home of this order; while they were comparatively rare in those of Europe. 

 In the latter country, we have four species only determined by paleontologists, 

 viz : 



Mosasaurus 2 



Liodon 1 



(?) Saurospondylus 1 



In North America, the species have been exactly determined from three 



regions, as follows : 



Crreensand of New Jersey. 



Mosasaurus 6 



Baptosaurus 2 



Clidastes 2 



Liodon 4 



(?) Diplotomodon 1 



15 

 Rotten limestone, Alabama. 



Mosasaurus 1 



Holcodus 1 



Liodon 3 



Clidastes -• 2 



7 

 Chalk of Kansas. 



Clidastes 10 



Sironectes 1 



Platecarpus - 11 



Liodon 4 



26 



' See Traiisactious of tUe Americau Philosophical Society, vol. XIV. 



17 c 



