210 



NORTH AMERICAN INDEX FOSSILS. 



364. A. cooperi Gabb. (Fig. 1482.) Cretacic. 



Larger and coarser than preceding, ribs more irregular, fre- 



FiG. 1482, Anisoceras cooperi, fragments, X M- (After Whiteaves, Mes. Foss., I.) 



Quently bifurcating or even trifurcating, with irregular rows of 

 nodes. 



Chico of California, and Nanaimo of Vancouver. 



Fig. 1483. Turrilites brazoensis, apical and adult whorls. (After Hill.) 



