50 8 C. Barrois— Review of Professor Hall's recent volume 
- 
portion as the rock becomes more calcareous. The Ortho- 
curious to see the fauna of the Cephalopods diminish in pro- 
E he O 
ceras are distributed in the Devonian formation as follows: 
Upper Helderberg group, including the Schoharie grit ._....--- 30 
Hamilton group 29 
“ 4 
Ciemwoe  8 See 19S 
Waverly “ 7 
e numerous and varied forms of the Schoharie grit are 
1 i and a 
Th 
usually imperfect; they occur in a coarse sediment 
openings are near together and become a single one of trilo- 
The Schoharie grit has furnished six species of 
cannot be determined. ‘ ; 
he existence of Cyrtoceras in America was first recognized 
by Conrad in 1888, but it is difficult to define its limits, and 1t 
