New Species of Fossils from Hudson River Group. 



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Heretofore there have been only two species known in this 

 genus. The oldest, Cyrtocerina mercurius, from the Taconie 

 rocks, the most elongated species and having the shorter 

 septa, and Cyrtocerina typica, from the Black River Group. 

 The species here under consideration is from the extreme 

 upper part of the Hudson River Group, which gives a range 

 to this genus, commencing below the Silurian rocks and 

 extending to the very top of the Lower Silurian system. 



