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 N iagara, near Lou- 
isville. Collection of the author. 
3. Upper surface of a jejune corallum, from the horizon and neighbor- 
hood of example 2. 
Hatysires nexus, Nov. Spec. Niagara. 
4. Oblique 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. 
