PLATE 67. 



Halysites catenulatus. Niagara. 



1. Upper surface of a portion of a corallum, in which the corallets are 



of average size; from the white clay of the Upper Niagara, near 

 Louisville. Collection of the author. 



2. Upper surface of a fragment whose corallets are below the medium 



size; from the ferruginous clay of the- Upper Niagara, near Lou- 

 isville. Collection of the author. 



3. Upper surface of a jejune corallum, from the horizon and neighbor- 



hood of example 2. 



Halysites nexus, Nov. Spec. Niagara. 



4. Oblkpie lateral view of a corallum from the Upper Niagara white 



clay, two feet below the Niagara and Devonian passage-beds, near 

 Louisville. Collection of Mr. McConathy. 



5. Upper surface of a divaricating chain, imbedded in its chert matrix; 



from the ferruginous clay of the Upper Niagara, just below the 

 passage-beds above referred to, near Louisville. Collection of the 

 author. 



