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. Niagara. 



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 swixdeknana. 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. 



