PLATE 34, 
THECIA MAJOR. Niagara. 
1. Upper surface of a corallum, gathered from its rock matrix twenty- 
five feet below the Niagara and Devonian passage-beds, near Lou- 
isville. Collection of the author. 
2. Under surface of a corallum, covered with an epitheca, from the white 
clay five feet below the passage-beds, near Louisville. Collection 
of the author. 
3. Upper surface of a fragment from the ferruginous clay of the Upper 
Niagara strata, near Louisville. Collection of the author. 
THECIA MINOR. Magara. 
4. Upper surface of a portion of a corallum from the upper white clay 
beds, near Louisville. Collection of the author. 
7. Upper surface of calcified tube-casts of a corallum [Labechia con- 
ferta ]. 
THECIA SWINDERNANA. Niagara. 
5. Upper surface of a fragment from the upper red clay strata, near 
Louisville. Collection of Mr. Nettelroth. 
6. Upper surface of portion of a corallum from the white clay eight 
feet below the passage-beds, near Louisville. Collection of the 
author. 
THECIA VETUSTA. Hudson River Group. 
8. Upper surface of a corallum incrusting Streptorhyncus planum- 
bonus, near Milton, Ky. Collection of the author. 
9. 10. Similar views of coralla from the same horizon and locality. 
Collection of Mr. Nettelroth. 
