FOSSILS OF THE CARBONIFEROUS. 255 
Surface covered with fine, undulating strive of growth that are crowded 
together irregularly, forming slight concentric undulations. 
The arcuate form of the body-whorl distinguishes this species from 
Platyceras acutirostris Hall (Geol. Surv. lowa, vol. i, pt. 2, p. 665, pl. xxiii, 
fig. LL) of the Lower Carboniferous of Indiana, ete., the most nearly allied 
species. 
Formation and locality—Lower portion of Lower Carboniferous lime- 
stone, in canon directly north of a small conical hill on east side of Secret- 
canon-road Canon, Eureka District, Nevada. 
Genus PLATYOSTOMA Conrad. 
Platyostoma inornatum nN. sp. 
Plate xxiv, figs. 3, 3a. 
Shell subglobose; spire elevated above the body whorl; volutions three 
or four, and perhaps a fifth very minute one, that is not preserved in the 
specimen illustrated. The outer volution expanding towards the aperture, 
but scarcely ventricose; aperture vertically ovate or subrhomboidal; the 
columellar lip appears to have been reflexed. 
The few fragments of the outer shell that are preserved show it to 
have been nearly if not quite smooth. 
This species resembles some forms of Platyostoma lineatum (ante, p. 185) 
of the Devonian of New York. 
Formation and locality—Lower portion of Lower Carboniferous lime- 
stone, in canon directly south of a small conical hill on the east side of Secret- 
canon-road Canon, Kureka District, Nevada. 
Genus EUOMPHALUS Sowerby. 
Buomphalus (Straparollus) subrugosus M. & W. 
Plate xviii, fig. 19. 
Euomphatus rugosus Hall, 1858. Geol. Surv. Iowa, vol. i, pt. 2, p. 722, pl. xxix, figs. 
14a-c. (Not Huomphalus rugosus Sowerby, 1849.) 
Serpula (Spirorbis) planorbites Geinitz, 1866. Carb. und Dyas in Nebraska, p. 2, pl. 
i, fig. 6, (not of Munster). 
