60 PALEONTOLOGY OF THE EUREKA DISTRICT. 
lobe; occipital ring strong, swollen towards the eenter, and bearing a short 
spine; occipital furrow well defined; dorsal furrows blended with the de- 
pressed interior slope of the fixed cheeks and frontal lobe; this causes the 
glabella to stand out prominently, although but little elevated above the 
- general surface of the head; fixed cheeks rather broad, with a rounded, 
ridge-like elevation near the eyelobes, and sloping inward to form a de- 
pressed space before reaching the glabella; eyelobes large, with an ocular 
ridge running towards the anterior lobe of the glabella; frontal lobe short 
and convex, merging into the fixed cheeks laterally, and in front into the 
strong furrow within the broad, marginal border; the border is convex and 
swollen at the center into a small protuberance; postero-lateral limbs nar- 
row and rather depressed. 
Surface finely granulose. 
The identification of the genus Anomocare is made with the illustra- 
tions given by Angelin, and, until we know more of the structure of the 
species under consideration, it is difficult to give any other generic refer- 
ence. No pygidie or remains of the thoracic segments were found in the 
same association. 
Formation and locality—Cambrian. In a limestone beneath the arena- 
ceous shales carrying the species of Olenellus, given on a previous page, 
and associated with 0. Gilberti and O. Howelli. West slope of Prospect 
Mountain, Eureka District, Nevada. 
Genus PTYCHASPIS Hall. 
Ptychaspis minuta Whitfield (?). 
Plate x, fig. 23. 
Ptychaspis minuta Whitfield, 1878. Ann. Rep. Wisconsin Geol. Surv., p. 55. Ibid., 
Geol. Wisconsin, vol. iv, p. 186, pl. i, figs. 25, 26, 1883. ‘ 
This is a very minute form, the head measuring only about 3™ in 
length. A comparison of the glabella and fixed cheeks, the only parts thus 
far discovered, with the description of the original type specimens from the 
Potsdam sandstone of Wisconsin, shows such close resemblances between 
the two that with our present knowledge it appears impossible to consider 
