198 POTTSVILLE FAUNA OF OHIO 



outline, and strongly convex; the beaks are situated about one-third 

 the length of the shell from the anterior margin. The front is rounded 

 with the posterior-inferior portion slightly produced; the posterior ex- 

 tremity is broadly rounded and slightly truncated above, while the 

 anterior extremity is more narrowly rounded. The surface is marked 

 by numerous prominent and regularly arranged concentric ridges 

 separated by broad deep furrows. There is, however, much variation 

 among individuals in the number, regularity, and prominence of the 

 surface markings. 



Dimensions. The measurements of separate right and left valves 

 of average size are respectively: height 13 mm., 14 mm., length 17 mm., 

 18 mm., convexity 3.5 mm., 4 mm. 



Horizon and locality. Lower Mercer limestone : Muskingum 

 County, Locality 43, c; Licking County: Flint Ridge, Localities 47, 49, 

 c. McArthur limestone: Vinton County, Localities 84, 85, c. 



Edmondia meekiana (Herrick)? 

 PI. X, fig. 6 



1887 Solenomya ? meekiana. Herrick, Bull. Den. Univ., Vol. 2, p. 30, PI. 4, Fig. 9. 

 Coal Measures: Flint Ridge, Ohio. 



Herrick's description: "Nearly quadrate, elongate, more than 

 twice as long as wide; sides parallel, straight; posterior outline gently 

 curved; anterior outline somewhat truncate, not produced; convexity 

 somewhat greatest near the beak, but entire valve nearly equally con- 

 vex, sloping gently and almost equally to the entire margin. Length 

 1.05 (inches), width .50." Surface marked by rather coarse, regular, 

 concentric undulations and covered entirely with fine, concentric lines. 



Dimensions. The measurements of a large specimen are: length 

 28 mm., height 16 mm., convexity of single valve 3.5 mm.; a smaller 

 individual measures: length 14 mm., height 8.5 mm., convexity of 

 single valve 2 mm. 



Remarks. About six separate valves of this species from the 

 Lower Mercer limestone of Flint Ridge and also a few specimens from 

 the McArthur limestone are among the collections studied. Our form 

 differs from Herrick's species Solenomya ? meekiana only in its slightly 

 less elongate outline, the length being a little less than twice the height. 

 Another similar species is referred to by Herrick as Solenomya ? anodontoi- 

 des, 1 but this form is less elongate than ours which seems to lie between 

 S. ? anodontoides and S. ? meekiana, although it resembles the latter more 

 closely. Herrick states that the two species mentioned above are 

 practically identical except that the latter is much more elongate. 

 'Herrick, C. L., Bull. Den. Univ., Vol. 2, p. 29, PI. 4, Fig. 11, 1887. 



