148 PALEONTOLOGY OF THE EUEEKA DISTEIOT. 



Genus ATHYEIS McCoy. 



Athyris Angelica Hall. 



Athyris angelica Hall, 1861. Fourteenth Ann. Eep. N. Y. State Cab. Nat. Hist., p. 99. 

 Hall, 1867. Pal. N. Y., vol. iv, p. 292, pi. xlvii, figs. 9-20. 



This species, in New York, is known only in the Chemung Group, a 

 horizon comparable with the upper beds of the Devonian of the Eureka 

 District, although the fauna is not as specialized as in the East. In all essen- 

 tial particulars the specimens from these widely separated localities are 

 specifically identical, with the exception of one feature, which has not been 

 observed in the New York examples. When the outer part of the shell, 

 with the imbricating lamella or lamelliform striae is exfoliated, the entire 

 surface is more or less marked by radiating striae. The form of the shell 

 varies, as in the New York specimens, from transverse to elongate, the latter 

 usually prevailing. 



Formation and localities. Devonian limestone, The Gate, northwest of 

 Eureka, and Newark Mountain, Eureka District, Nevada, 



Athyris (sp. undt.). 



A single specimen of this form with the shell exfoliated, except on the 

 upper portion, occurs at Lone Mountain, low in the Devonian. It resem- 

 bles Athyris cora, of the Hamilton and Chemung Groups of New York (PaL 

 N. Y., vol. iv, 291, pi. xlvii, figs. 1-7), but is probably a distinct species. 



Genus MEEISTELLA Hall. 

 Genus WHITFIELDIA Davidson. 



Meristella (Whitfieldia) nasuta Conrad (Sp.) 

 Plate iii, figs. 8, 8 a, 86. 



Atrypa nasuta Conrad, 1842. Jour. Acad, Nat. Sci. Philad., vol. viii, p. 265, figs. 8, 9. 

 Meristella nasuta Hall, 1860. Thirteenth Ann. Eep. N. Y. State Cab. Nat. Hist., p. 93. 

 elissa Hall, 1861. Fourteenth Ann. Eep. N. Y. State Cab. Nat. Hist., p. 100. 



Ibid., 186l>. Fifteenth Ann. Eep., pi. iii, figs. 21, 22. 



nasuta Hall, 1862. Fifteenth Ann. Eep. N. Y. State Cab. Nat. Hist, p. 160, 

 3. 17-19 of p. 161. 



