88 PALEONTOLOGY OF THE EUREKA DISTRICT. 
CRUSTACEA. 
Genus LEPERDITIA Roualt. 
Leperditia bivia White. 
Leperditia bivia White, 1874. Expl. and Surv. West 100th Merid. Prelim. Notice 
Invert. Foss., p. 11; ibid., vol. iv, pt. 1, p. 58, pl. iii, figs. 7 a-d, 1875. 
This species is very abundant in the upper beds of the Pogonip Group, 
at Lone Mountain, 18 miles northwest of Eureka, White Mountain, and the 
Fish Creek Mountains, Eureka District, Nevada. 
The original type specimens were from the Schell Creek Range of 
Nevada. 
Associated with this species we find two smaller species not unlike some 
varieties of DL. Canadensis (Can. Organic Remains, dee. iii, p. 92, pl. xi, figs. 
6, 7, 9, 10, 1858), the determination and illustration of which is left for fu- 
ture study. 
Genus BEYRICHIA McCoy. 
Beyrichia, sp.? 
This is an interesting species, as it is of the type of B. regularis Em- 
mons (Amer. Geol., pt. 2, p. 219, 1858), of the Hudson River Group of Ohio. 
Owing to the imperfect condition of the specimens its further identifi- 
cation is delayed in the hope of obtaining better material. It is associated 
with Leperditia bivia, at White Mountain, Eureka District, Nevada. 
Genus PLUMULITES Barrande. 
The presence of this rare genus in American strata, west of Ohio, has 
not hitherto been recorded, and now we have but a single plate to show it. 
This is triangular in its general form, with the basal margin sigmoidal and 
the surface ornamented with the characteristic lines parallel to the sigmoidal 
margin. It occurs in the lower portion of the Pogonip Group, on the 
southwest end of McCoy’s Ridge, Eureka District, Nevada. 
