TKIASSIC FOSSILS. 35 



R. iEQUIPLICATA, 71. S. 

 PL G, Fig. 37, and 37 a, b. 



Shell subglobose, convexity of the two valves equal. Beak 

 large, prominent, incurved, sides sloping eonvexly to the ends 

 of the hinge-line, beyond which they converge very gradually and 

 merge into the nearly straight basal margin. Surface marked by 

 fourteen nearly equal rounded ribs, which commence on the upper 

 valve at about one-third of the distance from the hinge, and on 

 the lower valve at a point opposite to the hinge. The two lateral 

 ribs on each side are oblique, and end abruptly anteriorly, but 

 are flat posteriorly. Between the rest are regular rounded grooves 

 of about the same size as the ribs themselves. No median sinus. 

 The four middle ribs extend a little further into the smooth part 

 of the surface, but differ in no other respect from the adjoining 

 ones. No surface markings have been detected. 



Length, 1.1 inch. Width, 1. inch. Thickness, .85 inch. 



From the "Cinnabar District," in the range east of the Humboldt Mountains. 

 Collected by Gorham Blake, Esq. 



SPIRIFER, Sow. 



S. HOMFRAYI, 11. S. 

 PL 6, Fig. 38. 



Shell long, narrow, ends rounded, most prominent below the 

 hinge-line. Upper valve with a broad, regularly concave, median 

 sinus, and six curved, subangular ribs on each side. Lower valve 

 with a broad rib, corresponding to the sinus in the opposite valve, 

 and five lateral ones. Area broad, shorter than the length of the 

 shell. Beaks mutilated. 



Figure, very slightly magnified. 



Locality ; A single distorted specimen found by Mr. Homfray in Star Cation, 

 Humboldt County, Nevada Territory, near his mill, associated with Tcrebratida 

 ITumboldtensift and Rhynchoncila linrjulata. 



