PLATE 51. 
CLADOPORA DENTATA, Nov. Spec. Devonian. 
1. Under surface of basal 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 FRANCISCI, 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 clay, near Louisville. Collection of Dr. Knapp. 
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. 
NicHousonta (Nov. Gen.) CANADENSIS. Devonian. 
6. Corallum incrusting Spirifera oweni, from the red clay of the Middle 
Devonian, near Louisville. Collection of Dr. Knapp. 
