PLATE 6. 



Colttmxopora. rati, Nov. Spec. Hudson River Group. 



1. Lateral view of the corallum figured in Plate 5, Fig. 1. 



Columxopora cribriformis. Hudson River Group. 



2. Lateral view of a pyriform corallum found in Nelson county. Collec- 



tion of the author. 



Columnaria alveolata. Hvdson River Group. 



3. Portion of the upper surface of a corallum found in Nelson countv. 



Collection of the author. 



