1883.] 



NATURAL SCIENCES OF PHILADELPHIA. 



165 



Genep.al Observations. 

 In the preceding pages there are described from the Idaho plio- 

 cene formation the following species : — 



Percidfe, 1 species. 



Cottidffi, 4 " 



Salmonidpe, 1 " 



Cyprinidfe, 11 " 



Catostomidifi, 2 " 



Cobitidse 1 " 



Siluridge, 1 " 



Raiidae, • • 1 " 



Total, 22 species. 



Of the above, all differ from existing species so far as known, 

 but three of the species which represent the Percidas, the Cobi- 

 tidx and the Silui-idse respectively, have not been exactly deter- 

 mined. All the species differ from those of the Oregon Lake (or 

 Lake Lahontan as it may prove to be). Of the families, all are 

 existing and all are represented on the North American Continent 

 excepting the Gobitidse, which are now confined to Ear-Asia. But 

 of these eight families four are not now found in the American 

 waters which empty into the Pacific Ocean, viz., the Percidae^ 

 Siluridse^ Cohitidse^ and Raiidse^ excepting that there is one 

 species of the Percidre in California. Five of the seven families 

 have not yet been found in the Oregon fossil lake basin, but as 

 two of them (Salmonidse^ Cottid^), are found in the existing 

 lakes of that region, they will probablj' be found in that deposit. 

 The above evidence is sufficient to prove that the Idaho pliocene 

 formation is distinct from any formation previously known. It 

 is older than the Oregon lake deposit. 



In addition to the fishes, three species of craw-fishes were dis- 

 covered in this formation by Capt. Clarence King. These I 

 named Astacus subgrimdialis, A. chenoderma, and A. hrevifor- 

 ceps} The mollusks of this formation have been described by F. 

 B. Meek, and they, like the fishes, determined it to be 'lacustrine 

 and fresh, as already stated by Prof. Newberry. The species are 

 stated by Meek^ to be distinct specifically, and in some cases 



' Proceedings Amer. Philos. Society, 1870, p. 605. 

 2 Proceedings Acad. Nat. Sci., Phila., 1870, 56. 



Loc. cit., Nov. 1870. 



