264 PALEONTOLOGY OF THE EUEEKA DISTEICT. 



PTEROPODA. 

 Genus CONULAKIA Miller. 



Conularia Missouriensis Swallow f 

 i Plate xxiii, fig. 4. 



Conularia Missouriensis Swallow, 1860. Trans. St. Louis Acad. Sci., vol. i, p. 657. 



The description given by the author of this species agrees so closely 

 with the specimen before me that in the absence of the type, or a good 

 illustration, it is identified with it. Both the Missouri and Nevada speci- 

 mens occur in the lower portion of the Lower Carboniferous limestone. 



Formation and locality. Lower portion of the Lower Carboniferous 

 limestone, Mokomoke Ridge, White Pine Mining District, Nevada. 



Genus HYOLITHES Eichwald. 



Hyolithes carbonaria, n. sp. 



Plate xxiii, fig. 3. 



Form an elongate triangular pyramid, gradually and regularly taper- 

 ing to an acute extremity; angle of divergence of the sides, 18. Trans- 

 verse section subovate, slightly convex on the ventral side, the lateral mar- 

 gins rounded, and the dorsal side a little more convex than the opposite 

 side. Aperture oblique, the ventral side being a little prolonged. Shell 

 rather thick. Operculum unknown. 



Surface with fine, concentric, radiating or longitudinal striae. 



Dimensions: length, ll mm ; diameter at aperture, 3.5 mm by 2 mm . 



In the cast a longitudinal groove is seen on the ventral face near each 

 lateral margin ; it extends only a little way back from the aperture. 



This pretty little shell has the form of Eyolitlies aclis Hall (Pal. N. Y., 

 vol v, pt. 2, p. 197), of the Devonian of New York, but it is more slender 

 and probably a much smaller species. Also compare with Hyolithes novellus 

 Barrande (Syst. Sil. Boheme, vol. iii, pi. xv, figs. 23, 24.) 



Formation and locality. Lower portion of Lower Carboniferous lime- 

 stone, in cailon directly south of a small conical hill on the east side of 

 Secret-canon-road Canon, Eureka District, Nevada. 



