110 



AMERICAN FOSSIL BRYOZOA. [bull. 173. 



TABLES OF GENERA AND SPECIES. 



These tables show the number of species of the various genera pres- 

 ent in the different geologic formations. The tables of the Trenton 

 and Cincinnati periods show also the number of species common to 

 two or more of the divisions and those restricted to one division. 



TRENTON. 



