69. CONTRIBUTION TO 



finer plications, sharper in outline. The differences are hardly more than of 

 varietal significance, however. 



The figured specimens were collected from the Warsaw Limestone at Lanee- 

 ville, Ind., and form a part of the collection of Mr. G. K. Greene^ 



ORBICULOIDEA PARVA, N. Sp., (Rowley). 



Plate 23. Figs. 24-25. 



The upper valve of this little shell is low, conical and circular. Apex ele- 

 vated, eccentric (almost central in the largest or type specimen). Ventral valve 

 unknown. 



The shell is very thin and marked by very fine, closely arranged, concentric 

 striae. 



The specimens examined vary in size from minute ones to those as large as 

 the type, and all came from the same nodule or coprolite, collected in the Knob- 

 stone shales at New Albany, Ind., by George K. Greene. 



CRANIA ROBUSTA, N. Sp., (Rowley). 



Plate 23. Figs. 26-27. 



Shell depressed, conical. Beak of the convex valve sub-central, slightly 

 curved toward the nearest side or border and fronting an ill-defined, triangular 

 area. Surface apparently smooth, save concentric lines of growth. 



The specimen figured is from the Knobstone Group, three miles west of 

 New Albany, Ind., and is in the cabinet of Mr. G. K. Greene. 



CRANIA DEPRESSA, N. Sp., (Rowley). 



Plate 28. Figs. 28-29. 



This shell is very much depressed, and has the beak very near the front, 

 but hardly defined. 



A few concentric lines of growth are present, but the surface is otherwise 

 smooth. The general outline is roughly quadrangular. 



The lower valve is unknown. The concave side of the upper valve as fig- 

 ured, shows the muscular scars. 



The type specimen is from the Middle Devonian (upper Helderberg Group) 

 Falls of the Ohio River. Collection of Mr. Geo. K. Greene. 



