180 University of Kansas Geological Survey 



group within the last twenty years. Perhaps we may expect 

 more definite knowledge concerning them in the immediate fu- 

 ture. There is no inherent improbability that the Alabama or 

 Mississippi species are not congeneric with the western ones, in- 

 asmuch as we know positively that one genus at least, Clidastes, 

 does occur in all these regions, and it does not seem at all un- 

 likely that all of them are common to the different horizons. 



? Platecarpus crassartus. 



Liodon crassartus Cope, Proc. Amer. Phil. Soc, 1871, 168. 

 Platecarpus crassartus Cope, Cret. Vert., 153, 268, pi. xxvi, ff. 4, 12. 



This species is known only from Cope's description. Its lo- 

 cality is given from Eagle Tail, in Colorado. The fact is, how- 

 ever, that the locality whence it was discovered is within the 

 borders of Kansas. I visited the precise place of its discovery 

 in company with Professor Mudge, who discovered it many 

 years ago. The horizon is not Niobrara, but clearly Fort Pierre. 

 The species does not belong in the genus Platecarpus ; of that I 

 feel confident. It evidently has strong relationships with 

 Brachysaurus , and I would have referred it to that genus save 

 for the free chevrons. As it is, I am not sure but that it may 

 belong there, or perhaps better in Prognathosaurus Dollo. 



The peculiar robust condition of the bones is not, however, 

 the most characteristic peculiarity of the species. Bones 

 wherever found in the Fort Pierre invariably have a solidity 

 and thickness never seen in the specimens from the Niobrara. 

 I am confident that the limb bones of the various forms known 

 from the Niobrara had the general robustness seen in this, but 

 have always been flattened and compressed in fossilization. 

 Better characters are found in their shape. Especially is the 

 relative size of the limb bones and vertebra? different from that 

 in Platecarpus, the limbs being evidently much smaller. Copies 

 of the principal figures given by Cope are reproduced in plate 

 xlv, which will enable the species to be again recognized. 

 I have no doubt but that future discovery will bring to light 

 much better specimens of this species from the Fort Pierre out- 



