224 PALEONTOLOGY OF THE EUKEKA DISTRICT. 



This species is related by its form to Athyris f polita Hall (Pal. N. Y , 

 vol. iv, p. 293), of the Chemung Group of New York, and also in some of 

 the specimens to Athyris trinudea (see Bull. Amer. Mus. Nat. Hist., vol. i, p. 

 50), of the Lower Carboniferous of Indiana, etc.; the beak of the ventral 

 valve, however, appears to be imperforate. 



Formation and locality. Lower portion of Lower Carboniferous lime- 

 stone in canon directly south of Conical Hill, on east side of Secret-canon- 

 road Canon, Eureka District, Nevada. 



Genus CAMAROPHORIA King. 



Camarophoria Cooperensis Shumard f 



Plate xviii, fig. 6. 

 Rhynchonella Cooperensia Shuinai cl, 1855. Geol. Surv. Missouri, pt. 2, p. 204, pi. (7, 4o-<7. 



With the exception of having fewer plications, the Eureka specimens 

 agree in all essential features with those from the Chouteau limestone of 

 Missouri, as described by Dr. Shumard. A comparison of specimens may 

 show the western form to be a distinct species, but the means of comparison 

 at present available leads to referring them as above. 



Formation and localities. Lower portion of the Carboniferous Group, 

 on the western slope of Richmond Mountain, and in limestone capping 

 Diamond Peak, Eureka District, Nevada. 



Genus TEREBRATULA Llhwyd. 



Terebratula hastata Sowerby. 

 Synonymy: See Mou. Brit. Foss. Braeb. Davidson, vol. ii, p. 11. 



With a number of specimens to compare with Mr. Davidson's beauti- 

 ful figures of this species we cannot find reasons for a specific separation of 

 the American form from that of Europe. Some of the Eureka shells are a 

 little more expanded in front, but scarcely more so than examples figured 

 by Mr. Davidson. 



Formation and locality. Lower portion of Lower Carboniferous lime- 

 stone in canon directly south of a small conical hill, on east side of Secret- 

 cafion-road Canon, Eureka District, Nevada. 



