﻿NORWOOD AND PRATTEN ON CHONETES. 31 



We inscribe this very beautiful fossil with the name of Mr. Logan, Chief of the 

 Geological Survey in the British Provinces of North America, on account of our high 

 appreciation of his labors in a geological field in which we spent some years. 



Explanation of the Figures. — PI. II., fig. 12, a. View of the dorsal valve of an adult 

 specimen, magnified. 



Fig. 12, b. Curvature of the dorsal valve. 



Fig. 12, c. Length of the shell. 



