234 PALEONTOLOGY OF THE EUEEKA DISTRICT. 



Genus PTERINEA Goldfuss. 



Pterinea Piutoensis, n. sp. 

 Plate xix, fig. 10. 



Shell very small; body part obliquely elongate, narrowing towards 

 the beak, which extends a little above the hinge-line. The anterior ear is 

 small, rounded in front, and somewhat compressed; posterior ear large, 

 compressed, extending beyond the posterior extremity of the valve, pointed 

 at the end, and slightly sinuous behind. The body of the valve ranges at 

 an angle of about 40 with the cardinal margin. 



Surface marked by strong concentric striae. 



This little shell has a length of 10 mm on the cardinal line and a height 

 at right angles to this of 6 mm . It is unlike any species known to me occur- 

 ing at this horizon. 



The generic reference to Pterinea is made in the absence of any 

 knowledge of the interior characters. It is very probable that it belongs 

 to the genus Actinopera, but with the material at hand this cannot be deter- 

 mined. 



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

 northeast side of canon north of Pinto Peak, Eureka District, Nevada. 



Genus LEPTODESMA Hall. 



Leptodesma, sp. ? 



Two species of this genus are represented in the collections from the 

 lower portion of the Carboniferous. One is quite strongly marked, and is 

 allied to Leptodesma Rogersi Hall, of the Hamilton Group of New York, 

 and the other to L. complanatum Hall, from the Chemung Group, New York 

 (See Pal. N. Y., vol. v, pt. 1, pp. 1 76, 227). Each is represented by a single, 

 not very well-preserved specimen, which renders a specific identification 

 very uncertain and unsatisfactory. 



