94 NORTH AMERICAN INDEX FOSSILS. 



In the Onondaga beds of New York, Canada, Michigan, and 

 Western States. 



116. C. labiosa (Billings). (Fig. i$o,a-fr.) Devonic. 

 Stems smaller 2nd more frequently branching, often reuniting. 



Oblique (2 to 5 mm. in diameter) subcircular orifices with a promi- 

 nent convex lip. 



Abundant in the Onondaga of New York, Canada, Michigan and 

 the Falls of the Ohio. 



117. C. roemeri (Billings). Devonic. 

 Cylindrical or compressed stems, about 5 mm. or less in diame- 

 ter with large oblique orifices, which merge into an indefinite in- 

 terstitial surface or into angular pits. 



In the Hamilton group of Canada and at the. Falls of the Ohio. 



118. C. pulchra Rominger. Devonic. 

 Similar to preceding but with circular orifices, more than a tube- 

 diameter apart, and often at the summit of a small elevation. 



In the Onondaga of Canada, Michigan and the Falls of the Ohio. 



119. C. robusta Rominger. Devonic. 

 Large compressed cylindrical stems from 10 to 20 mm. thick 



and often forming net-like expansions covering several square feet. 

 Oblique orifices with strong semicircular lips. 



In the Onondaga beds of Michigan and the Falls of the Ohio, 

 and in the Hamilton of Michigan. 



XLII. Striatopora Hall. 

 Coral stock of simple dividing cylindrical branches, with thick- 

 walled corallites, opening in rounded apertures, which are sur- 

 rounded by polygonal depressed calices, the sides of which are 

 striated by rudimentary septa. Occasional septal spines, tabulae 

 and mural pores present. Sil.-Dev. 



120. S. flexuosa Hall. (Fig. 151.) Siluric. 

 Bifurcating branches. Polygonal expansion of cells deep, and 



bounded by angular ridges, vertically striate, the striae becoming 

 fainter upward. Calices circular at the base. 

 In the Niagara beds of New York, etc. 



121. S. linnaeana Billings. Devonic. 

 Orifices of unequal size through intercalation of smaller ones, 



moderately oblique, 2 mm. in diameter and narrowing in diameter. 



