GUELPH FAUNA IN THE STATE OF NEW YORK 155 



FIG. 



7 An internal cast of the shell, showing the rounded character of 



the volutions (M. logani) 



8 Another internal cast of a shell, showing the rounded volu- 



tions, which are all represented as too angular 



Coelidium cf. vitellia Billings (sp.) 



Page 67 



9 Section of the shell, showing the wide perforation of the 



axis ; rather badly restored at the apex 

 10 Exterior view of the same specimen 



All specimens are drawn natural size and are from the Guelph 

 beds at Rochester (Arey collection). 



