.1XTH0Z0A—TABULATA. 



87 



lites curving outward, with their mouths nearly at right angles to 

 the main axis of the coral, from 1 to 2 mm. or more in diameter, 

 closed in perfect specimens by concentrically striated opercula. 

 Pores generally in single rows ; tabulae complete averaging 1.5 mm. 

 apart, squamae generally not prominent. 



In the Onondaga of western New York, Canada, Michigan, 

 Ohio and at the Falls of the Ohio, and in the Hamilton of Canada 

 and Michigan. 



92. F. hamiltoniae Hall. (Syn. F. billingsi Rom.) (Fig. 140.) 



Devohic. 



Corals in form of hemispheric heads with the base covered by 

 a wrinkled peritheca. Adult corallites up to 2.5 mm. in diameter, 

 generally surrounded by smaller immature ones. Mural pores in 

 two rows, frequently obscure, tabulae perfect, sometimes crowded, 

 more generally from 2 to 4 mm. apart, not infrequently with mar- 

 ginal notches. Easily recognized by its distant perfect tabulae. 



Abundant in the Hamilton groups of west- 

 ern New York, Canada, etc. 



93. F. alpenensis Winchell. Devonic. 



Differs from F. Jiamiltonice in its manner of 

 growth, which results in the formation of 

 rounded or tuberose masses, with generally 

 only a small space for attachment; in the 

 somewhat smaller corallites, which are rounded 

 tubes on the interior owing to the thickening, 

 of the walls, and in the more crowded tabulae. 

 Very common in the Hamilton (Traverse) group of Michigan. 

 Also in northwestern Canada (Manitoba, etc.). At Alpena a vari- 

 ety forms large heads in the coral reefs. 



94. F. canadensis (Billings). (Fig. 141.) Devonic. 



Generally a more or less flat or undulating expansion, sometimes 

 digitate. Circular tubes, about I mm. in diameter, are scattered 

 subregularly between small angular 

 ones, of about one third their size. 



Simple tabulae in the smaller, and 

 tabulae complicated by squamae in the 

 larger ones. Opercula often present. 



In the Onondaga limestone of New 

 York, Canada, Michigan, Indiana and 

 Kentucky. 



FlG. 140. Favosites 

 hamiltoni(Z. 



Fig. 141. Favosites canadensis 

 (after Billings). 



