it: 



Found at "West 

 Hamburg, Erie 

 County." (Hall.) 

 Found also in the 

 Stictopora and De- 

 missa beds, at Sec- 

 tion 5, Eighteen Mile 

 Creek (rare). 





Kate " 



Fig. 71. Tceniopora exigua. Natural size, and a 

 portion enlarged, x (after Hall and Simpson.). 



Genus ACROGENIA. Hall. 



[Ety. : Akros, sharp; genea, growth.] 

 (1881: Trans. Albany Inst., Vol. X., p. 193.) 



"Zoarium" (Bryozoum) ''ramose, proliferous; consisting 

 of flattened branches, two 

 proceeding from the truncate 

 termination of the previous 

 one, and continuing growth in 

 the same manner. Branches 

 striated below, flattened and 

 cell ulifer ous above. Inter- 

 cellular structure vesiculosa 

 Apertures arranged in longi- 

 tudinal rows." (Hall, Pal. 

 N. Y., Vol. VI., p. xx.) 



ACROGENIA PRO LIFER A. 



Hall. (Fig. 72.) (Pal. N. Y., 

 Vol. VI., p. 267, PI. LXIII.) 



Bis tinguish ing Ch a ra cters — 

 Peculiar growth and jointage ; 

 small circular apertures; weak 

 peristomes; prominent luna- 

 ria ; continuous ridges separat- 

 ing apertures. 



Found in the " Hamilton group, Eighteen Mile Creek, Erie 

 County, N. Y." (Hall, explanation of plates. ) 



Fig. "i~. Acrogenia prolifera. Natural 

 size, and a portion enlarged, x 6 (after Hall 

 and Simpson). 



