370 Proceedings of the Ohio State Academy of Science. 



fascicles ; these are crossed by fine concentric stride which give 

 a finely crenulated surface when viewed through a lens. Coarser 

 concentric undulations of growth also mark the shell at irregular 

 distances [Whitfield, 1895]." 



Length 30-35 mm. ; width 35-40 mm. 



As pointed out by Whitfield this shell is decidedly var- 

 iable. However, the ventral valves of most specimens may be 

 characterized by their flattened appearance and the somewhat 

 sudden prominence and distortion of the beak. At the extreme 

 margin, the valve is bent upwards. 



Horizon and localitv. — Maxville limestone. 

 Upper zone: Mouth of Buckeye Fork, Fultonham; Gladstone 



Mills?, Thompson Residence?, Below Thompson Residence, 



White Cottage. 

 Lower zone : Bridge Gully, ]\It. Perry-Fultonham. 

 Undetermined zone : Harper Shaft, Olive Furnace. 



PRODUCTUS PILEiFORMIS— McChesney. 



1859. Productits pileiforuiis. McChesney, Desc. New Paleozoic Foss., 

 p. 40. 

 Kaskaskia limestone : Chester, Illinois. 

 18fll. Productus p.ileifonnis. Whitfield, Ann. N. Y. Acad. Sci., "Vol V, 

 p. 582, pi. 13, figs. 13, 14. 

 Maxville limestone : Ohio. 

 1895. Productus pileiforuiis. Whitfield, Geol. Surv. Ohio, Vol. VII, 

 p. 470, pi. 0, figs. 13, 14. 

 Maxville limestone : Ohio. 

 1909. Productus pileiforuiis. Girty, U. S. Geol. Surv., Bull. 377, p. 26, 

 pi. 2, fig. 7. 

 Caney shale : McAlester quadrangle, Oklahoma. 

 1911. Productus pileiformis. Girty, U. S. Geol. Surv., Bull. 439, p. 44, 

 pi. 4, figs. 1, 2. 

 Moorefield shale : Batesville quadrangle, Marshall quadrangle, 

 Arkansas. 



Description. — Shell larger than medium, fragile, decidedly 

 concavo-convex with a reflected margin. 



Pedicle valve strongly curved in the posterior region and 

 decidedly recurved at the anterior margin. Valve pointed at 



