366 G. H. Gh'ty — Upper Permian in Western Texas. 



Of the pelecypods the folio wing species were collected : 



Aviculopecten (Pterinopecten ?) sp. 



Avicalopecten ? sp. 



Streblopteria (3 sp.) 



Entolium? (3 sp.) 



Lima n. sp. 



Euchondria ? sp. 



Camptonectes ? (2 sp.) 



Avicula n. sp. 



Myalina ? near M. squamosa Sow. 



Myoconcha n. sp. 



Modiola?sp. 



Edmondia? sp. 



Cypricardinia? sp. 



Macrodon ? sp. 



Axinus securus Shum. ? 



The aspect of this fauna also is quite varied. The shells are 

 as a rule small and preserved as internal casts, so that it is 

 difficult in most cases to ascertain the characters of really 

 generic value. There is a general absence of the types which 

 characterize the Upper Carboniferous or even the Permian of 

 the Mississippi Yalley. The development of the pectinoid and 

 mytiloid groups is rather striking. The genus Myoconcha^ of 

 which I seem to have virtual representatives, has not before 

 been recognized in J^orth America, and Camptonectes is new 

 among our Carboniferous faunas. The latter is abundantly 

 represented by individuals, and has every external appearance 

 of belonging in the Mesozoic genus. 



Gastropods are rare and in size generallj^ minute. So far 

 only the following have been found : 



Pleurotomaria ? group of carbonaria (2 sp.) 

 Pleiirotomaria ? (n. gen. ?) sp. 

 Worthenia ? sp. 

 Euconispira ? sp. 

 Orthonema ? sp. 

 Holopella ? sp. 



But little need be said of the gastropod fauna, in which there 

 is nothing striking, except the absence of our familiar Carbon- 

 iferous species. 



Of the cephalopods, at a horizon where novel and interesting 

 ammonoid types might be expected to occur, only an imperfect 

 and undetermined species of Temnocheilus has been found. 



]^o Crustacea have yet been noted, except Phillipsia peran- 

 nulata Shumard, which occurs in abundance in the " dark 



