658 



NORTH AMERICAN INDEX FOSSILS. 



LIV. Eccyliopterus Remele. 



Contiguous or disconnected whorls with the structure of Ophileta 

 but with the upper carina drawn out into a thin vertical "collar," 

 which is not always preserved. Ordovicic. 

 174. E. beloitensis U. and S. (Fig. 906, c-e.) Ordovicic. 



Rapidly enlarging, whorls in contact, coiling nearly in same 

 plane, outer surface convex, moderately high collar. 



Stones River of Wisconsin and Kentucky. 



Fig. 906. a, b, Ophiletina sublaxa (6, enlargement of surface); c-e, Eccyliopteris 

 beloitensis; f, g, E. owenensis ( g = section ) ; h, i, Helicotoma planulata ; J, k, H. 

 tennesseensis. (After Ulr. & Sc. , Pal. Minn.) 



175. E. owenensis Meek and Worthen. (Fig. 906,/, g.) 



Ordovicic. 

 Smaller, with the sides flat, and the collar, when preserved, very 

 high and thin. 



Galena (Trenton) of Minnesota and Illinois. 



LV. Helicotoma Salter. 

 Differs from Ophileta in having a low spire rising above the 

 outer volution, a deep umbilicus, and the whorls rounded on the 

 under side. The carina is generally high and sharp. Ordovicic- 

 Devonic(?). 



176. H. planulata Salter. (Fig. 906, h, i.) Ordovicic. 

 With three to six strong, simple or double spirals on the outer 



side of the whorls. 





