592 



NEW YORK STATE MUSEUM 



Barrandeoceras natator Billings (sp.) 



Page 454 

 See pi. 33 



I Exterior view of a large specimen, showing the rate of growth, 

 the costation of the younger stages and the evolute direction 

 of the gerontic volution 



The original is from the dove-colored Chazy limestone on the east 

 shore of Valcour island, and now in the New York State Museum. 



