Cincinnatian and Lexington Fossils 65 



is of only moderate length, and which shows a tendency toward 

 the disappearance of the exterior plications of the fold and sinus. 

 Shells of this type( plate iv. figs. 11 A, B) occur in the Liberty bed 

 at Versailles, Indiana, and for these the name Platystrophia cypha- 

 vcrsaillcschsis is suggested. Similar specimens occur in the Blan- 

 chester division of the Waynesville bed along the road from 

 Moores Hill to Holman, north of Hogan creek (plate iv, figs. 

 13 A.B). 



Platystrophia acuminata, James, from the Mount Auburn or 

 lower Arnheim at Cincinnati, Ohio, judging from its relatively 

 great width and acute postero-lateral angles, belongs to the Platxs- 

 trophia cypha group of shells, and may be merely a young speci- 

 men of one of those forms in which the lateral plications on the 

 fold and in the sinus are better developed. The type (plate vi. 

 figs. 13 A,B) numbered 1562, is preserved in the James collection 

 in the Walker Museum, at Chicago University. 



Platystrophia clarksvillensis, sp. nov. 



rPlate III, figs. 4.3.) 



In the Clarksville division of the Waynesville bed there is a 

 form of Platystrophia which bears some resemblance to Platystro- 

 phia laticosta. (Fig. 4.) It dififers chiefly in having narrower, 

 more numerous plications, the number of lateral plications being 

 7 to 9; the four plications occupying the fold are more nearly of 

 the same size, resulting in a relatively broader and less angular 

 fold and sinus. These specimens closely resemble Platvstrophia 

 acntilirata but differ in having a less obese convexity when seen 

 from the anterior side. The specimens possibly may be in the line 

 of development from Platystrophia laticosta toward Platystrophia 

 acntilirata. They are especially common in the Clarksville divi- 

 sion of the Waynesville bed, but they begin in the Fort Ancient 

 division, are found in the Blanchester division, and continue into 

 the Liberty bed. Typical forms of Platystrophia acntilirata occur 

 in the Whitewater bed. 



Platystrophia acutilirata, Conrad. 



(Plate III, figs. 6, 7, S A, B.) 



Conrad described Platystrophia acntilirata as coming from the 

 Silurian shale at the Falls of the Ohio river, Kentuckv. Since his 



