40 PALEONTOLOGY OF THE EUREKA DISTRICT. 
Genus DICELLOCEPHALUS Owen. 
Dicellocephalus bilobatus H. & W. 
Dicellocephalus bilobatus Hall & Whitfield, 1877. Geol. Expl. Fortieth Parallel, vol. iv, 
p. 226, pl. 2, fig. 36. 
This species was founded on a pygidium having a bilobed posterior 
border, collected in the Eureka District by the geologists of the Fortieth 
Parallel Geological Survey. The same character of pygidium was obtained 
by the present survey in the upper beds of the Cambrian, on the east side 
of the Sierra Valley, east of Pinnacle Peak, Eureka District, Nevada. 
Dicellocephalus Osceola Hall. 
Plate ix, fig. 25. 
Dikelocephalus osceola Hall, 1863. Sixteenth Ann. Rep. N. Y. State Cab. Nat. Hist., 
p. 146, pl. x, fig. 18; pl. vil, fig. 49? 
Original type from the Potsdam sandstones at Osceola Mills, State of 
Wisconsin. 
A comparison of the Nevada specimens, consisting of the glabella and 
fixed cheeks, with the type example of the species in the American Museum 
collection, shows such a strong specific identity of the parts preserved that 
there is little doubt, with our present information, but that they belong to 
one and the same species. 
Formation and locality—Cambrian. Prospect Mountain Group, upper 
portion, on ridge north of the Dunderberg mine, Eureka District, Nevada. 
Dicellocephalus nasutus, n. sp. 
Plate x, fig. 15. 
Glabella and fixed cheeks, when united, subquadrangular in form, the 
width being about three-fourths of the length. The glabella is broadly 
conical, rounded in front, and with its convex surface marked by two 
slightly impressed pairs of anterior furrows, and a pair of more strongly 
marked posterior furrows that penetrate obliquely inward to a shallow 
