244 POTTSVILLE FAUNA OF OHIO 



by broad furrows; and a middle layer on which the ridges are almost as 

 sharply marked as on the outer layer, and which is covered by extremely 

 fine but distinct radiating lines. Fig. 3, PL XIV, shows the middle 

 layer of an individual with a portion of the outer layer remaining 

 around the beak. 



Dimensions. A specimen of average size from the Lower Mercer 

 limestone measures: length 19 mm., height 15 mm., convexity of left 

 valve 7 mm. 



Horizon and locality. Of general distribution throughout the 

 Lower Mercer and McArthur members, c. Upper Mercer member: 

 Perry County, near Somerset, Locality 63, r. 



Astartella sp. 



Description. A small, crushed pelecypod, probably belonging to 

 the genus Astartella, occurs in great abundance at two localities, one 

 in the Lowellville limestone ? and the other in the Lower Mercer, dis- 

 tant from each other, yet faunally very similar and unique. A some- 

 what square posterior outline, long cardinal margin, prominent beaks, 

 and fine, regular, concentric lines characterize the form. It is, how- 

 ever, top poorly preserved to be identified specifically. The measure- 

 ments of a specimen of average size are: length 9.5 mm., height 6.5 mm., 

 length of cardinal margin 6 mm. 



Horizon and locality. Lowellville member ?: hear Holbein, Mus- 

 kingum County, Locality 20, a. Lower Mercer limestone: Rock Hollow, 

 Vinton County, Locality 34, a. 



Genus Cypricardinia Hall 



Cypricardinia ? carbonaria Meek 

 PL XI, fig. 14 



1871 Cypricardinia ? carbonaria. Meek, Proc. Acad. Nat. Sci. Phil., p. 163. 



Lower Coal Measures: Newark, Ohio. 

 1875 Cypricardinia ? carbonaria. Meek, Pal. Ohio, Vol. II, p. 432, PI. 19, Figs. 8 a, b. 



Lower Coal Measures: Newark, Ohio. 



Meek's description. "Shell small, longitudinally oval, less than 

 twice as long as high, the widest (highest) part being under the poster- 

 ior extremity of the hinge; rather gibbous, with usually a broad im- 

 pression extending from the beaks obliquely backward and downward 

 to the middle of the base of each valve; anterior side extremely short 

 or nearly obsolete, convex, and rounded; posterior side broader, more 

 compressed or cuneate, with its upper edge straight and sloping ob- 

 liquely backward to the regularly rounded posterior margin; base 



