330 



U niversity of California Publications. 



[Geology 



that of certain fishes, while characters of the skull are unques- 

 tionably reptilian. 



Since the publication of the original description of this form 

 Wiman 2 has described from Spitzbergen a number of specimens 

 which he refers to the ichthyosaurs, but which are interpreted 

 by Merriam 3 as probably representing omphalosaurians. The 

 specimens obtained by Wiman occurred in beds which are con- 

 sidered as representing the Middle Triassic, and the saurian 

 fauna is in general quite similar to that of the Middle Triassic 

 of the West Humboldt Range, in which the type specimen of 

 Omphalosaurus was found. 



EVIDENCE PRESENTED BY NEW MATERIAL 

 In the material most recently obtained from the Middle Trias- 

 sic of Nevada there are two closely associated specimens showing 

 a great number of large, bluntly-conical teeth resembling in 

 general the teeth of Omphalosaurus. Thus far a study of these 

 specimens has failed to reveal the exact relationships of all of 

 the bony elements exposed. The characters of the dentition are 

 much better shown than in the type specimen of Ompltalosaurus. 

 One specimen (no. 19452) shows the dentition of a part of 



Pig. 1. Omphalosaurus ($), sp. A portion of the dentition of the man- 

 dible (?). No. 19452, natural size. 



what appears to be the dentary. The dentigerous area exposed is 

 a strongly convex surface. The largest and best preserved teeth 

 are situated at the rounded anterior portion. Running pos- 



2 Wiman, C, Bull. Geol. Inst. Upsala, vol. 10, p. 140, 1910. 



3 Merriam, J. C, Univ. Calif. Publ. Dept. Geol., vol. 6, p. 325, 1911. 



