66 



NORTH AMERICAN INDEX FOSSILS. 



the later stages of growth. Septa simple, without carinae, extend- 

 ing to the center of the calyx where they are more or less twisted. 

 One or more fossulae present in some species. Tabulae in central, 

 cystose structure in peripheral areas. Ord.?-Carb. 



33. C. robustum Rom. Middle Devonic. 



Generally large, growth irregular, calyx deep, septa low, thin 

 and sharp, the longer reaching the center and uniting. Fossula 

 faint. 



Hamilton group of western New York, Ontario and Michigan. 

 Also at the falls of the Ohio. 



34. C. conatum Hall. (Fig. 100.) 



Middle Devonic. 



Fig. 100. Cyatho- 

 phyllum conatum{Y2\. , 

 N. Y.). 



Fig. ioi. Campophyllwn torquium with cross section (Ind. 

 Geol. Surv. ). 



Cylindrical, generally small, and of irregular growth. Septa 

 strong and regular reaching the center. No fossula. Has many 

 characters of Blothrophylhnn. 



In the Hamilton group of New York and Ontario. 



35. C. alpenense Winch. Devonic. 



Cylindrical to conico-cylindrical, rather smooth; calyx deep 

 with steep sides marked by septa of a triangular cross-section. 

 Tabulae well developed in central portion. 



Abundant in the Hamilton beds of Michigan. 





