70 NORTH AMERICAN INDEX FOSSILS. 



Onondaga of Canada, Michigan, etc. 



XIX. Pachyphyllum E. & H. 



Compound corallites bounded by polygonal walls, each with a 

 central conical elevation, at the top of which is a crater-like pit. 

 Septa extending over the outside of the cone as low ridges or 

 costae. The longer septa extend to within a short distance of the 

 center. Dev. 



45. P. woodmani (White). (Fig. 108.) Upper Devonic. 



Growing in convex or hemispheric masses from I to 6 inches in 

 diameter; crater rims strongly elevated, sometimes more than an 

 eighth of an inch. Crater deep and variable in diameter. 



In the Upper Devonic of Iowa, etc. 



XX. Strom bodes Schweigger. 



Coral composed of superposed layers or laminae, on the surfaces 

 of which are polygonal depressions representing the calices with 



Fig 



. 108. Pachyphyllum woodmani (N. FlG. 109. Strombodes pentagonus (after 

 Y. State Mus. Rep.). Lambe). 



the central part marked by an abrupt circular pit. Calicinal surface 

 with radial septal ridges, which unite in the center in a papillose 

 projection. Sil.-Dev. 



46. S. pentagonus Goldfuss. (Fig. 1C9.) Siluric. 



Calices shallow from 10 to 15 mm. in diameter; center with a 

 styliform columella, septa sharp at the pit, becoming low rounded 

 ridges at the margins. 



In the Niagara beds of Michigan, the Falls of the Ohio, etc. 



