256 PALEONTOLOGY OF THE EUREKA DISTRICT. 



8traparollu8 (Euomphalus) rugosus Meek, 1872. U. S. Geol. Surv. Nebraska, p. 230 



pi. vi, figs. 5 a, 6; pi. xi, figs. 4 a, &. 

 Straparollus (Euomplmlus) submgosus Meek & Worthen, 1873. Geol. Surv. Illinois, 



vol. v, p. 607, pi. xxix, figs. 11 a-c. 



The example of this species in the collection has the essential features 

 observed in the specimens from the Coal Measures of Illinois, Nebraska, etc., 

 and no specific differences are recognized between the form from Nevada 

 and those of the Mississippi Valley region. 



Formation and locality. Lower portion of the Carboniferous Group, on 

 the east slope of a small conical hill on the east side of the Secret-canon- 

 road Canon, Eureka District, Nevada. 



Genus BELLEROPHON Montfort. 



Belferophon majusculus, n. sp. 

 Plate xxiii, figs. 1, la; plate sxiv, fig. 6. 



Shell thick and strong, very large, subglobose; body volution subglo- 

 bose, expanded a little at the aperture, marked by a well-defined median 

 carina ; outer lip with a strong sinus in front, rounded at the sides, somewhat 

 reflexed and greatly thickened over the umbilical areas, entirely concealing 

 the openings. Inner margin of the columellar lip very much thickened, 

 boss-like, extending out into the aperture and giving the latter a broadly 

 subreniform outline; the outer lip probably extended over a portion of the 

 columellar lip, but the specimens at hand do not show this clearly. 



Surface characters mostly obliterated, a few of the stronger lines or 

 wrinkles of growth alone remaining; these curve gently forward between 

 the dorsal carina an.d the umbilicus. 



Dimensions: greatest length, 12 cm ; breadth at umbilicus, 7.5 om ; at ap- 

 erture, ll cm . Aperture, 3.5 cm by 7.5 cm in a specimen 10 cm long, by 6.5 om 

 wide at the umbilicus. 



This large Bellerophon is most nearly related to Bellerophon costatus 

 Sowerby, as figured by De Koninck (Anm. Foss., plate xxvi, fig. 2 a-e). It 

 differs in the direction of the lines of growth, form of aperture, and the 

 thickening of the columellar lip. Bellerephon crassus M. and W. (Geol. Surv. 

 111., vol. ii, p. 385, pi. xxxi, figs. 16 a, &), from the Lower Coal Measures of 



