6o 



NORTH AMERICAN INDEX FOSSILS. 



Guelph of New York; Monroe of Michigan and Canada. 

 48. P. marcellense (Vanuxem). (Fig. 1264.) Devonic. 



Fig. 1264. Protokionoceras marcellense, X Yz^ with enlargement of surface. 

 (After Hall.) 



Slender, tapering rapidly; camerae of moderate depth; siphuncle 

 small, excentric, scarcely nummuloidal. Longitudinal strise fine, 

 with finer, slightly undulating, transverse striae. 



