CRETACEOUS FOSSILS. 201 



LIMA, Brug. 



L, SHASTAENSIS, n. s. 



PL 33, Fig. 100. 



SHELL small, compressed, irregularly subelliptical, equivalve; 

 anterior side and base forming a regular curve, the posterior 

 margin of the base rounding up rather abruptly to the posterior 

 side, which is straight; ears very small, the anterior triangular, 

 the posterior narrow, almost linear ; posterior umbonal slope very 

 narrow. Surface ornamented, by twenty or twenty-one promi 

 nent, straight, radiating ribs, with the interspaces of equal size. 



Greatest length, from beak to base, .6 inch; antero-posterior diameter, .45 inch; 

 depth of single valve, .09 inch. 



Rare in the Shasta Group, Cotton wood Creek, Shasta County. 



I have two specimens of this shell, on of which is somewhat mutilated, but 

 they fortunately show both valves. The species is less oblique than L. microtis, 

 and the ornament of the surface is entirely different, as it is also from L. appressa. 

 The latter species is narrower Above than the present one, it is a straighter shell, 

 and the anterior ear is larger. 



L. MULTIRADIATA, n. S. 

 PI. 33, Fig. 101. 



There is but a single mutilated specimen of this fine shell in the collection, with 

 its corresponding impression in the matrix. The lines of growth on the latter, 

 together with some, less distinct, on the shell itself, supply the outline, except of a 

 small portion of the posterior margin, and of the ear on that side. The specific 

 characters, so far as shown, are as follows : 



SHELL (right valve) large, oblique, compressed subelliptical; 

 anterior side forming a regular curve to the middle of the base, 

 very slightly sinuous above, under the ear ; posterior portion of 

 the basal margin much more narrowly rounded than in advance, 

 uniting by a broad curve above, with the posterior side, the upper 

 half of which seems to have been nearly straight ; the anterior 

 ear seems to have been long and narrow. Surface convex a little 



PAL. VOL. II. 27 



