3i8 NORTH AMERICAN INDEX FOSSILS. 



extremity of the cephalon being more broadly produced, giving 

 to it a shovel-like appearance. 



Helderbergian of New York and New Jersey;* Oriskany of 

 New Jersey. 



i6i. H. dekayi (Green). (Fig. 1631.) Devonic. 



Fig. 1 63 1. Honialonof us dekayi [rtAwctd). (After Hall.) 



Pygidium nearly smooth, the trilobation and segmentation being 

 obsolescent. Surface of test pitted. 



Hamilton and Marcellus of New York and New Jersey. 



