40 PALEONTOLOGY OF THE EUREKA DISTRICT. 



Genus DICELLOCEPHALUS Owen. 

 Dicellocephalus bilobatus H. & W. 



Dicellocephalus bilobatus Hall & Whitfleld, 1877. Geol. Expl. Fortieth Parallel, vol. iv, 

 p. 226, pi. 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. 



DikelocepJialus osceola Hall, 1863. Sixteenth Ann. Kep. N. Y. State Cab. Nat. Hist., 

 p. 146, pi. x, fig. 1; pi. vii, 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 



