PLAT E X X X 1 X. 



Fig. I. Streptelasma PATULA. Niagara group, Point Detour. 



2. spongaxis. " " 



3. Cyathophyllum radicula. " Drummond's Island. 



Two elongated specimens on the right a somewhat different form. Louis- 

 ville. 



4. Streptelasma cunulus. Niagara group, Point Detour. 



