656 



NORTH AMERICAN INDEX FOSSILS. 



LI. Phanerotinus Sowerby. 

 Like Straparollus, but with the whorls disconnected, forming an 

 open spire. Devonic-Carbonic. 



168. P. laxus Hall. (Fig. 901.) Devonic. 

 Whorls round, gently enlarging in very loose 



spiral almost in same plane. 



Onondaga and Hamilton of New York. 



169. P. eboracensis Hall. (Fig. 902.) 



Devonic. 



Fig. 901. Phanero- Like Strapavollus rudzs, but loose-coiled, often 

 """ axm - \ er showing scars of attachment of foreign objects. 



Hamilton of New York. 

 170. P. paradoxus Win chell. (Fig. 903.) Mississippi. 



Fig. 902. Phanerotinus eboracensis. (After Fig. 903. Phanerotinus para- 

 Hall,Pal. N. Y., V.) doxus. (After Hall, Pal. N.Y.,V.) 



Like P. laxus, but the inner whorls depressed below plane of 

 outer, and less loosely coiled. 



Kinderhook-Burlington of Iowa and Missouri. 



LI I. Ophileta Vanuxem. 



Shells with depressed spire and flat base, consisting of narrow 

 whorls which enlarge very slowly and are in contact throughout. 

 They are flattened or gently convex on the under side, and have a 

 faint lower and stronger upper keel, the latter ending in a deep 

 > -shaped apertural notch. Ordovicic. 

 171. 0. complanata. (0. compacta Salter.) (Fig. 904.) 



Ordovicic. 



Of numerous whorls, flat on the lower and strongly concave on 

 the upper side, outer face flat and nearly vertical, upper surface 

 sharply keeled. Diameter 1 to 1 ]/ 2 inches. 



