8o 



NORTH AMERICAN INDEX FOSSILS. 



71. C. dichotoma Grabau. (Fig. 129.) Middle Devonic. 



Prostrate, tubes with flattened lower and carinated upper portion, 

 and abruptly up-bent circular calices. Buds in pairs, at right 

 angles to each other. Cysts small. 



Fig. 127. Ceratopora jacks'oni. 



Fig. 128. Ceratopora jacksoni. 

 Transverse and longitudinal section, 

 X2. 



Fig. 129. Ceratopora dichotoma. Nat. size (a) and enlarged [d-d). 



In the Hamilton beds of New York, Ontario, Michigan and the 

 Falls of the Ohio. 



72. C. intermedia (Nicholson). Middle Devonic. 



Small cylindrical, loosely branching corallites forming a colony 

 which probably grew erect. Epitheca smooth with only growth 

 lines. 



