68 PROCEEDINGS OF THE ACADEMY OF 



its known characters, not evidently merely specific, with the type 

 of the genus Clinopistha, which I had previously supposed to be 

 confined to the Coal-measures. It has the same short gibbous 

 form, thinness of substance, posterior position of the beaks and 

 ligament, surface markings, and even the same obscure interiial 

 radiating striae. Indeed, if it were not for its rather more nar- 

 rowly rounded, and more protuberant, instead of slightly trun- 

 cated, posterior or shorter end, somewhat less gibbous beaks, and 

 faintly sinuous base and flanks, it would scarcely be possible to 

 distinguish it from the Coal-measure form by any external cha- 

 racter, excepting the white chalky texture of the shell merely due 

 to its state of preservation. The valves are a little displaced in 

 the only good specimen I have seen, but the beaks certainly give 

 some evidence of being slightly unequal, that is, of the left one 

 lapping slightly upon the other, as in the typical species from the 

 Coal-measures. 



Locality and position. Same as last. 



SANGUINOLITES ? SANDUSKYENSIS, Meek. 



Sliell approaching a longitudinal-oblong or trapezoidal outline, 

 moderately convex, a little more than twice as wi<le as high, and 

 slightly narrower anteriorly than behind ; cardinal margin straiglit, 

 equalling about three-fifths the entire length ; basal margin nearly 

 straight and subparallel to the hinge, or slightly ascending ante- 

 riorly ahnig its entire length, and rounding up a little more 

 graduall}^ into the front than behind ;• posterior extremity com- 

 pressed, obliquely truncated above, and rather narrowly rounded 

 to the base below ; anterior end very short, sloping from the 

 beaks above, and rather narrowly rounded at the middle ; beaks 

 depressed nearly or quite to the hinge-line, compressed, and 

 placed near the middle of the anterior third ; posterior umbonal 

 slopes not angular, or even prominently rounded. Surface only 

 showing a few irregular furrows and slight undulations of growth, 

 most distinct below the middle of the valves. 



Length, 2.t0 inches ; height at the posterior end of the hinge, 

 1.20 inches; do. under the unibones, 1.04 inches; convexity, about 

 0.52 inch. 



I know nothing of the hinge of this shell, and merely refer it to 

 the genus SanguinoUtes provisionally. Indeed, until palceonto- 

 losists can aorree in regard to which one of the several shells that 



[June 6, 



