72 



NORTH AMERICAN INDEX FOSSILS. 



51. E. rugosum E. & H. (Figs, in ; 113, a.) Siluric. 



Corallites less than 10 mm. in diameter, with prolific calicinal 



budding, outline cylindrical with subregular constrictions, epi- 



Fig.iii. Eridophyllum rugosiwi (Ind. Geol. Survey). 



thecal prolongations spiniform. Septa extending to within a short 

 distance of the center, which is occupied by tabulae. 



Common in the Niagara beds of Indiana, Kentucky, etc. 



52. E. vernuillianum E. & H. (Fig. 112.) Devonic. 

 Tubes 7 to 10 mm. in diameter, distant about their own diameter. 



Strong epithecal proliferations. A sharp thin inner wall enclosing 

 a space about 2 mm. in diameter not crossed by septa. 



In the Onondaga beds of northern Ohio and adjacent regions. 



53. E. colligatum (Billings). Devonic. 

 Cylindrical stems expanding at regular and uniform intervals so 



as to unite in polygonal outlines, after which they contract and 



