FOSSILS OF THE CAMBRIAN. 45 
and situated opposite the central portion of the glabella; frontal limb 
obsolete except the round, thick, marginal rim just in advance of the 
glabella; the posterior limbs are broken away at a little distance from the 
dorsal furrows. 
Surface, as seen under a strong magnifying glass, with fine inoscu- 
lating, flattened lines surrounding minute round or irregularly oval spaces. 
~ Formation and locality—Upper beds of the Cambrian just south of the 
Hamburg mine, and in the same canon, Eureka District, Nevada. 
Dicellocephalus ? quadriceps H. & W. 
Plate ix, fig. 24, 
Dikellocephalus ? quadriceps Hall & Whitfield, 1879. Geol. Expl. Fortieth Parallel, vol. 
iv, p. 240, pl. i, figs. 37-40. 
Type specimens from the base of Ute peak, Wahsatch Range, Utah. 
A careful comparison of the Wahsatch specimens with those from 
Nevada fails to give sufficient specific distinction to separate them on the 
evidence afforded by the material at hand. A small glabella with portions 
of the fixed cheeks attached is figured on plate ix, fig. 23, to show the 
peculiar form of the glabella and the disappearance of the very faint 
glabellar furrows, scarcely shown in the specimens from Utah; this repre- 
sents one extreme of the species, while the specimen illustrated in the 
Paleontology of the Geological Exploration of the Fortieth Parallel exhibits 
the other, or more mature form. 
The generic reference is open to question, but with our present material 
little more can be done with it. 
Formation and localities—Cambrian. Prospect Mountain Group, base 
of Secret Canon shale, New York Canon, and in Cambrian limestone on 
the west side of the Eureka District on the Antelope Valley slope, near the 
plain, Eureka District, Nevada. 
Dicellocephalus ? expansus, n. sp. 
Plate ix, fig. 19. 
Glabella elongate subquadrangular, or subclavate, the base about one- 
fifth narrower than the front; surface convex and without perceptible fur- 
