FOSSILS OF THE CARBONIFEROUS. 259 
The slope of the spire of L. bella is more like that of the minute Chem- 
nitzia levigata Deshayes (Leth. Rossica, pl. xlii, figs. 6a,b) of the Tertiary. 
Formation and locality=—Lower portion of Lower Carboniferous lime- 
stone, in canion directly south of a small conical hill on the east side of Secret- 
canon-road Canon, Eureka District, Nevada. 
Genus PLEUROTOMARIA Defrance. 
Pleurotomaria nodomarginata McChesney. 
Plate xviii, fig. 15. 
Pleurotomaria nodomarginata McChesney, 1860. Desc. New Species of Fossils, p. 70. 
Trans. Chicago Acad. Sci., 1869, vol. i, p. 47, pl. vii, figs. 1 a-c. 
Notwithstanding that Mr. McChesney gives the Hamilton Group as the 
horizon from which P. xodomarginata was obtained, the identification is here 
made with a shell coming from the Lower Carboniferous of the Eureka Dis- 
trict. This conclusion is arrived at only after the most careful comparisons, 
which appear to leave very little if any doubt of the specific identity of the 
Nevada and Missouri shells. 
Formation and locality —Lower portion of the Carboniferous Group, east 
side of Secret-canion-road Cation on east slope of a small conical hill, Ku- 
reka District, Nevada. 
Pleurotomaria Nevadensis, n. sp. 
Plate xxiv, figs. 2, 2a. 
Shell turbinate; spire elevated, height and width subequal; volutions 
five or six, expanding quite regularly to within a half of a volution of the 
aperture, when it becomes more ventricose; body volution angulated, 
depressed convex above and rounded below; umbilicus small. Aperture 
broadly oval to subcircular. 
Surface marked by strong, regular, revolving lines above and below 
the peripheral band, crossed and cancellated by finer concentric strie that 
cut into the revolving lines and give them a fine nodose appearance. ‘The 
concentric strie are directed a little backward from the suture to the band; 
