182 PALEONTOLOGY OF THE EUREKA DISTRICT. 



Genus CYPRICARDINIA Hall. 



Cypricardinia indeuta Conrad (Sp.). 

 Plate v, fig. 14; pi. xv, fig. 11. 



Cypricardites indenta Conrad, 1842. Jour. Acad. Nat. Sci. Philad., vol. viii, pt. 2, p. 



244, pi. xii, fig. 12. 



inflata Conrad, 1842. Ibid., p. 246, pi. xv, fig. 2. 



Cypricardinia inflata, var. subequivalvis Hall & Whitfield, 1872. Twenty-fourth Ann. 

 Rep. N. Y. State Museum Nat. Hist., p. 189. Idem, Twenty-seventh 

 Ann. Rep., 1871, pi. xi, figs. 2-4. 



indenta Hall, 1883. Pal. N. Y., vol. v, pt. 1; Plates and Explanations, 

 p. 19, pi. Ixxix, figs. 6-23. 



The Nevada specimens agree closely with those from New York and 

 the Falls of the Ohio, no apparent variations occurring in a number of speci- 

 mens except, it may be, in some young shells, a figure of one of which is 

 given on plate v, fig. 14. 



Formation and locality. Lower Devonian of Atrypa Peak. Eureka Dis- 

 trict, Nevada. 



GASTEROPODA. 

 Genus PLATYCERAS Conrad. 



Of the eight species of Platyceras from the Lower Devonian horizon, 

 five are identical with species of the Upper Helderberg Group of New York, 

 viz: Platyceras carinatum Hall, P. conicum Hall, P. dentalium Hall, P. nodo- 

 sum Conrad, and P. Thetis Hall (for descriptions and synonyms, see Pro- 

 fessor Hall's beautiful monograph of the Devonian Gasteropoda of the State 

 of New York, Pal. N. Y., vol. v, pt. 2, 1879), and three appear to be distinct 

 from any described forms. 



Platyceras Conradi, n. ep. 

 Plate xvi, figs. 1, 1 a. 



Shell strongly arcuate, the apex incurved, oblique, and resting against 

 the right side of the body whorl ; body whorl increasing very gradually in 

 size from the inner whorl to the aperture ; prominent on the back and some- 



