i 



The hexactinellid sponge Hydnoceras bathense Hall & Clarke. i/6 natural size. This and the followhig plate slow 

 ful preparation and others lie buried in the rock. The blocks represent a small portion 



ies of slabs recently put on exhibition. About 250 sponges have been made visible by < 

 : sponge plantation, in the Chemung rocks at Bath, N. Y. 



