418 A. HYATT TRIAS AND JURA IN THE WESTERN STATES. 



Coroniceras claytoni. 

 Ammonites nevadanum, Gabb (pars). 



This species is founded upon a specimen associated with Arnioceras 

 nevadanum and labelled in the same hand, probably of Gabb's own 

 writing, Ammonites nevadanus, G. 



The young have in the ananeanic substage (the previous stage being' 

 covered) stout, gibbous whorls with coarse tubercles such as are often 

 found in young of Coroniceran species. These are on the genicular 

 angles and do not increase proportionatel}^ in size during the subsequent 

 growth of the shell. As the whorl grows they spread internally into true 

 costse, which become perfected during what is probably the paraneanic 

 substage. The history of the keel and channels cannot be given, the 

 abdomen being covered. The adult has whorls and costse which remind' 

 one of some specimens of Coroniceras lijra or Coroniceras bisulcatum, this 

 American form being intermediate in its aspect between these two species. 



The ribs are well defined and lyra-like, with similar tubercles on the 

 geniculse. The channels are deep, somewhat narrow and smooth, and 

 the keel is prominent, showing well above the channel ridges on the 

 outer whorl. 



UPPER LIAS FOSSILS FROM THE BLUE MOUNTAINS, OREGON* 



Pecten acutiplicatus^ Meek. 

 Lima sinuata, " 



Lima recticostata, '' 



Loc, Beaver creek. 



This species, one of the most characteristic forms of the Hardgrave 

 sandstone fauna of Taylorville, is represented by four specimens. Three 

 of them are sufficiently perfect to show the characteristics of the species, 

 and the third is a fragment of large size. 



Pholadomya nevadana. 



Pholadomya nevadana, Gabb. Am. Jour. Conch., vol. v, p. 10, pi. 5, fig. 7. 

 kingi, Meek. Ann. Rep. U. S. Geol. Surv. Ter., 1872, p. 473. 

 Loc, Beaver creek. 



This species is identical with that mentioned in my table of Hardgrave 

 sandstone fossils as Pholadomya, n. sp.,t the supposed European congener 

 of which was the P. ambigua, Sow., of the Upper Lias. 



* These fossils all belong to the Condon collection, as mentioned above, under the heading of 

 " Lias in California, Nevada and Oregon." 

 t Trias and Jura at Taylorville, p. 402. 



