PLATE 5. 



1. 46. 3. Macltjrea magna. (Pag. 26.) 



1 a. The Upppr surface parlially deniuled of the shell, showing the striic with the smooth cast beneath. This 



is a perfect representation of tlic shell, except that the minute terminal volution is not shown. 

 1 h. Side view of a cast of the shell, showing the depressed turbinate form and flat spire. 

 I c. View of the lower surface, somewhat worn ; showing the large umbilicus, which is partially fdled witli 



stony matter. 

 I (/. A vertical section of the shell, near, but not directly through the centre of the spire ; showing several 



volutions, and the deep umbilicus. Such sections of the shell are not unusual in the rock, and they are 



generally vertical to the lines of deposition. 

 I e. A view of the shell worn down from the lower side, as it very commonly appears upon the weathered 



surfaces of the rock at Chazy. 



