370 rroiwdiitf/s of the Ohio State .Iciidciiiy of Science. 



fascicles ; these are crossed In- line concentric stride wiiicli give 

 a Iniely crenulated surface when viewed tlirough 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 ^'entral valves of most specimens may be 

 characterizerl 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 localifx. — Maxville limestone. 

 Upper zone: Mouth of lUickeye Fork, Fultonham ; (Gladstone 



Mills?. Thompson Residence?, Below Thompson Residence, 



Wliite Cottage. 

 Lower zone: Bridge Gull}'. Alt. Perry-Fultonham. 

 Undetermined zone: Harper Shaft. Olive Furnace. 



PRODUCT us PILEiFORMIS- McChesney. 



1859. Prodnctns pilciformis. McChesney, Desc. Xew Paleozoic Foss., 

 p. 4n. 

 Kaskaskia limestone: Chester, Illinois. 

 18!»1. Prodiictus pileifoniiis. \\hithelcl, Ann. X. \. Acad. Sci., Vol V, 

 p. -^S-i, pi. 18, figs. 13, 14. 

 Maxviile limestone: Ohio. 

 189o. Prodiictus pileifoniiis. Whitfield, Geol. Surv. Ohio, Vol. VII, 

 p. 4711, pi. !i, figs. 18, 14. 

 Maxviile limestone : Ohio. 

 l!M):i. Prodiictus pileifoniiis. Girty. U. S. Geol. Surv., Bull. 877, p. 20, 

 pl. •-'. fig. 7. 

 Caney shale: McAkster quadrangle, Oklahoma. 

 l!ill. Prodiictus pilciformis. Girty. U. S. Geol. Surv., Bull. 430, p. 44, 

 pl. 4, figs. 1, •-'. 

 Mo(jrefield shale : Batesville <|uadrangle, Marshall quadrangle, 

 Arkansas. 



Descri[^tiou. — ."-^hell larger than medium, fragile, decidedly 

 concavo-convex with a reflected margin. 



Pedicle valve strongly curved in the ])osterior region and 

 decidedlv recurved at the anterior margin. A'alve pointed at 



