PL'ATE 51. 



Cladopora dentata, Nov. Spec. Devonian. 



1. Under surface of l)asal expansion and rear lateral view of portions 



of fronds of a corallum from the Lower Devonian, Falls of the 

 Ohio. Collection of Dr. Knapp. 



Cladopora FRANCiscr, Nov. Spec. Devonian. 



2. Front Lateral view of fragment from the Lower Devonian, Falls of 



the Ohio. Collection of Dr. Knapp. 



Striatopora huronensis. Niagara. 



3. Fragment imperfectly freed from the matrix ; from the Upper Niagara 



white chxy, near Louisville. Collection of Dr. Knaj^p. 



Eridophyllum sentum, Nov. Spec. Niagara. 



4. Lateral view of a fragment from the ferruginous clay of the Upper 



Niagara, near Louisville. Collection of Dr. Knapp. 



Lyellia puella, Nov. Spec. Niagara. 



5. Upper surface of a corallum from the Upper Niagara white clay, near 



Louisville. Collection of Dr. Knapp. 



NiCHOLsoNiA (Nov. Gen.) canadensis. Devonian. 



6. Corallum incrusting Spirifera oweni, from the red clay of the Middle 



Devonian, near Louisville. Collection of Dr. Knaj)p, 



