GEOLOGICAL SURVEY OF THE TERRITOEIES. 347 



the species here described, the bases of the teeth ar« enlarged and 

 deprived of cementum coat, but there are no true roots. 



The maxillary bone terminates in a narrowed extremity, with obtuse 

 termination, as in Stratodus. The vomer in one of the species is acumi- 

 nate at one end, and supports a short series of teeth ; the middle portion 

 in a double row. All the teeth are without pulp cavity. 



The only indication of the mode of succession of the teeth is furnished 

 by the specimen of O. anceps. Here a small excavation appears on the 

 inner side of the basis of the tooth. The absorption, commencing at this 

 point, no doubt removes the basis so that the crown falls away. 



The name used was applied by Dr. Leidy to a fish erroneously referred 

 by Agassiz and Dixon to Saurodon^ Hays. He did not characterize it ; 

 and until the barbed palatine teeth, characteristic of it, are discovered 

 in our species, their reference to it will not be fully established. In the 

 parts preserved they appear to be identical. The general affinities of 

 the genus will receive new light, from materials now in my possession 

 and not yet developed. 



The Sphyrcena carinatayCope, (Hayden's Report, Wyoming, &c., p. 424,) 

 probably belongs to CimoUchthys. 



ENCHODUS, Cuvier. 



Eemains of species of this genus occur in the Cretaceous strata of 

 Kansas. I discovered a tooth belongiag to one of them in the matrix 

 beneath the vertebrse of Ulasmosaurus platyurus. Dr. Leidy described 

 a species from the Cretaceous formations of the Upper Missouri region, 

 which he called U. shumardii. The prem axillary of a rather large spe- 

 cies was obtained by my expedition • but the species is not determinable. 

 The diameter of the basis of the tooth is .012 meter. The long tooth of 

 ,a species of medium size was detected, the Enchodus calliodon, Cope. 

 (Spec. nov. Unchodus sp., Cope, Hay den's Surv. Wyoming, &c., p. 424.) 



SELACHII. 



Remains of sharks and rays are far less abundant in the Cretaceous 

 of Western Kansas than in New Jersey, and are much exceeded in 

 abundance by the physostomous Actinopteri, as the present account in- 

 dicates. In the region near Fort Hays and Salina, sharks' teeth are 

 more frequently found. Those from near Fort Wallace belong to but 

 two species of the genus. Galeocerdo Mull. Renl. 



GENERAL OBSERYATIONS. 



The following species have been described from the Cretaceous forma- 

 tion of Kansas : * 



Saurodontld^. 



Portheus molossus, Cope. 

 thaumas, Cope. 

 Ichthyodectes anaidcs, Cope. 



ctenodon, Cope. 



JiamatuSj Cope. 



jyrognathus, Coi)e. 



7nultidentatuSj Cope. 



* The species here enumerated are all described in the Proceedings of the American 

 Philosophical Society for February, lb72. 



