154 PALEONTOLOGY OF KENTUCKY. 



Terebratula harmonia. HALL. 



Plate XVII., figures 1, 2, 3 and 4. 

 Terebratula harmonia, Hall. Pal. H. Y., Vol. 4, p. 3881867. 



Shell of more than medium size ; ovate or sub-spatulate ; tapering somewhat 

 abruptly to the beak, compressed at the margins, but convex in middle ; base 

 regularly curved. 



Ventral valve regularly arcuate from beak to front, moderately convex in 

 the middle ; a little gibbous above, and depressed convex or slightly concave 

 towards the front ; the upper part narrowing ; the beak much extended, atten- 

 uate and arcuate, but not closely incurved ; apex perforated, the slope to the 

 cardinal margin scarcely concave ; deltidial plates large. 



Dorsal valve moderately convex, sometimes a little more prominent along 

 the middle in the upper part, and depressed towards the front and sides. 



Surface marked by fine concentric lines of growth ; the substance of the 

 shell finely punctate. 



This species resembles to a certain degree Ter. sullivanti, but it is. more regu- 

 larly arcuate from beak to front of the ventral valve, and has a regularly 

 rounded base, while Ter. sullivanti has a truncate or sinuate front. Its well 

 marked regular form in larger specimens will easily identify it. 



Formation and Locality. Found in the corniferous limestone at and around the Falls of the Ohio, 

 in Kentucky and Indiana. It is a somewhat rare species. Prof. Hall received the original specimens, 

 from which he made his description and illustrations of this species, from the late Dr. James Kiiapp, who 

 collected the same at the Falls of the Ohio. 



Terebratula jucunda. HALL. 



Terebratula jucunda, Hall. Pal. N. Y., Vol. 4, p. 3901867. 



Shell of medium size ; sub-circular or very broadly ovate ; length and width 

 about equal ; regularly rounded in the margins of the basal half, but abruptly 

 converging to the ventral apex in upper half. 



Ventral valve moderately convex ; gibbous in the umbonal region, sloping 

 in a gentle, regular curve to the base and baso-lateral margins, showing a faint 

 mesial depression ; beak obtuse and arched over the umbo of the opposite 

 valve ; apex truncated by a rounded foramen. 



Dorsal valve less convex than the ventral, but regularly arched all over the 

 surface, with the exception of the cardinal angles, which are somewhat in- 

 flated. The specimen before me shows a faint elevation in the basal half, 

 corresponding with the sinus of opposite valve. 



Surface is marked by fine concentric striae or lines of growth. My specimen 

 measures in length and width a little more than three-eighths of an inch. 



Formation and Locality. Occurs in the corniferous limestone in Jefferson county, Kentucky, and 

 in Clark county, Indiana, 



