INDIANA PALEONTOLOGY. 70. 



PRODUCTUS PARVICOST ATUS, N. Sp, (Rowley) 



Plate 23. Figs. 30-31. 



Shell rather small, finely plicate. Ventral valve very gibbous. Length 

 greater than the width. The ventral valve incurved and rounded at the cardi- 

 nal line. The rapid convex growth or bending of the ventral valve throws the 

 gide of the shell, near the hinge line, into folds or- crumples, crossfng the plica- 

 tions a little obliquely. Irregularities of growth, may be due to injur}', and 

 change the direction of the plications at such places, but spines are apparently 

 entirely wanting. 



The dorsal valve is greatly concave and has the same fine stri;e. Lateral 

 folds, and is devoid of spines. 



This little Productus belongs to a we. I defined group of shells of varying 

 sizes, and occurring from the base to the top of the Carboniferous. 



A beautiful form occurs at Louisiana, Mo., in the Burlington Limestone, 

 of larger size and of greater proportional length. 



Productus Parvicostatus occurs in the Knobstone Group, 3 miles west of 

 New Albany, Ind.. and the types are in the collection of Mr. G. K. Greene. 



PLATYCERAS C I R C U L A R I S, N. Sp. (Rowley.) 



Plate 23. Figs. 32-33. 



Shell ventricose. Spire slightly inroUed; the body of the shell rather 

 rapidly expanding to the almost perfectly circular aperture. The concentric 

 strife almost obliterated in the silicification of the shell. 



The circular outline of the aperture and the slightly curved spire make it 

 easy to identify this species. 



The type comes from the Warsaw group at Lanesville, Ind.. and is in the 

 collection of Mr. G. K. Greene. 



LEPETOPSIS LEVETTEI White. Rowley. 



Plate 23. Figs. 34-35. 



This specimen is figured here, merely to call attention to the fact that the 

 species is not confined to the Warsaw group from which the type specimen 

 came, but is also found in the Keokuk limestone. 



It is one of a number of species of fossils common to the two groups and 



