SHUMARD—GASTEROPODA. 627 
surface of volutions marked with a prominent, medium, re- 
volving carina, and two smaller ones above and below ; these 
crossed by a very fine, closely crowded strie of increase, 
which are scarcely visible except under a magnifier. 
Length, 0.72; width, 0.28. : 
This species resembles somewhat closely IL angulata of 
Phillips, but is a shorter and more robust species, and the 
volutions are less sharply angulated. 
Occurs in the Coal Measures of Young County, 9 miles 
east of the Indian Reserve. Texas State Collection. 
OrtTHIs CoLoRADOENSIS, N. sp. 
crossed by about thirty, rounded radiating strie, which are 
Sometimes simple and sometimes bifurcated. 
ave seen are, 
he a 
length, 0.50; width, 0.58; but most of the specimens before 
in my cabinet from the Potsdam Sandstone of ert 
which, however, has only been found as casts in fi 
