136 



NORTH AMERICAN INDEX FOSSILS. 



Fig. 1388. Agoniatites expanms, X K- (After Hall, Pal. N. Y., V.) 



Hamilton of New York; also represented by varieties in the 

 Naples Fauna. 



Manticoceratida {Frimordialidcs, pars.). 



LXXVII. Manticoceras Hyatt. 



Compressed goniatites, with rounded venter, and often strongly 

 involute whorls; suture with broad, lateral saddle, sharp lobes, 

 and a high, medially divided, ventral saddle. Devonic. 



201. M. intumescens Bey rich. (Fig. 1389, a, Z?.) Devonic. 

 Of medium size; whorls embracing one half or more; umbilical 



angles rounded; venter strongly rounded, sides flat. 



Naples shales of New York, Iowa, Michigan, and Hay River, 

 Canada. 



202. M. rhynchostoma Clarke. (Fig. 1390, &, J.) Devonic. 

 Very large ; sides somewhat less flattened than in preceding, 



umbilical angle somewhat more abrupt. 

 Naples shales of New York. 



