REPORT ON PAL^EONTOLOGICAL COLLECTIONS 



ble more than any species known to me, in having- its siphuncle 

 tliougli not so much so as in his 0. lateral/', and in having its septa 

 be separated by spaces equaling- about one-fifth instead of only on 



eter of the shell. 



Locality and position. — East side Ruhv Valley: latitude, 40° 

 115° 20' west. Probably Lower Carboniferous. 



JURASSIC SPECIES. 



RADIATA. 



EOHINODERMATA. 



Genus PENTACRINITES, Miller. 



Pentackinites (unilt. ap.). 



Numerous fragments of 



in the Jurassic beds near th. 

 /'. (isfrr'isais, Meek and Ha; 

 same locality, in having a 

 though it may possibly belo 

 variable in form. 



more' slender and much less , 

 ng to the same species, the col. 



M0LL0SCA. 





LAMELLIBBANCHIATA. 







Genus OSTREA, Linn. 







Ostrea Engelmakni, Meek. 



Chirm I-:,u/ehn<t»»i, Meek, (Jn 

 Upper Mo., 73, 



toS 



i^^JnI^'L^ximu. 



The collection c 

 compressed, rather th 

 truncated, and provid 

 to about fifteen irreg 

 which do not usually 

 the border, which is i 

 but not imbricating-. 



Length (of the h 



iii and 

 ed wit! 

 : ular, r 



extent 

 isuallv 



Musci 



I only upper valves of this spe 

 subovate, or more less irregula 

 i a broad but short area: surfai 

 Qoderately distinct, rather ror 

 1 upon the umbonal region, bl 

 thin; lines of growth regular ai 

 dar scar rather large, ovate an< 

 specimen), 3.50 inches; breadtl 



much thinner shell, and differs remarkably m the length ot the area ot the upper value, 

 which is, in none of the specimens brought in, more than one-third as long as in 

 individuals of 0. Marshii of the same size, nor is it so concave in the middle as in that 

 species; while its plications are not so prominent or angular. 



It is also somewhat similar to a form referred by Prof. Jules Mareou in his Geology 

 of North America, pi. iv, fig. 4, to 0. Marshii. The shell now under consideration, 



