252 PALEONTOLOGY OF THE EUREKA DISTRICT. 
Genus SCHIZODUS King. 
Schizodus cuneatus Meek. 
Plate xx, fig. 8. 
Schizodus cuneatus Meek, 1875. Pal. Ohio, vol. ii, p. 336, pl. xx, fig. 7. 
There does not appear to be any points of specific difference between 
the Ohio shell illustrated by Mr. Meek and the examples of this species 
from Nevada. The latter are proportionally a little narrower, but this may 
be owing to the state of preservation, as the Ohio shell is compressed in a 
shale, and the Nevada specimens retain their natural convexity and outline. 
Formation and locality —Lower portion of the Carboniferous group, on 
the eastern slope of a small conical hill on the east side of Secret canon- 
road Canon, Eureka District, Nevada. 
Schizodus deparcus nD. sp. 
Plate xxii, fig. 5. 
Shell large, transversely suborbicular, moderately convex; umbonal 
ridge rounded and passing into the postero-dorsal slope without any per- 
ceptible angle being developed. Beak small, elevated, incurved, and sit- 
uated a little anterior to the center of the shell. 
Surface smooth as far as known, except a few radiating lines on the 
postero-dorsal slope. 
Anterior muscular scar not large, ovate in outline; posterior scar elon- 
gate, and crossed longitudinally by two slightly depressed lines, probably 
from the radiating lines of the postero-dorsal slope of the shell. Pallial line 
simple. 
Dimensions: height, 4.25™; width, 5°"; convexity or depth of right 
valve, 1.5°™. In size this species approaches Schizodus cuneatus (ante). It 
differs in being less erect, less angular in outline, and in having a smooth 
surtace. 
Formation and locality—Lower portion of Lower Carboniferous lime- 
stone on east slope of a small conical hill on the east side of Secret-canon- 
road Canon, Eureka District, Nevada. j 
