GASTROPODA— EUOMPHALIDJE. 



657 



In the Beekmantown (and Upper Potsdam ?), widely distributed 

 throughout North America. Also European. 



Fig. 904. Ophileta cotnplanata. Umbilical (6) and upper view ; a, outer keel ; d, 

 inner angle. (After Salter, Can. Org. Rem., Dec, I.) 



172. 0. bella Bill. (Fig. 905.) Ordovicic. 



• Whorls more rounded than preceding, basal portion less flat, 

 spire less sunken, fewer whorls, upper keel nearly central ; growth 

 lines coarse, subsquamose. 



Div. P, Quebec group, Newfoundland. 



Fig. 905. Ophileta bella. (After Billings.) 



LIII. Ophiletina U. and S. 



Like Ophileta, but with a distinct slit-band on the upper carina. 

 173. 0. sublaxa U. and S. (Fig. 906, a, b.) Ordovicic. 



Small, flat above, concave below (reversed in var. depressd), final 

 whorl free ; upper surface with two, outer with one median carina, 

 a fourth at the baso-lateral angle. 



Stones River of Minnesota, Wisconsin, and Illinois ; varieties 

 in Tennessee and Trenton of Minnesota. 



