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. 



Dikelloceplialus f quadriceps Hall & Whitfield, 1879. Geol. Expl. Fortieth Parallel, voL 

 iv, p. 240, pi. i., figs. 37-40. 



Type specimens from the base of Ute peak, Wahsatch Eange, 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 ? expausus, 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- 



