PLATE LV. 



GrAMMYSIA N0D0C08TATA. 



Page 360. 



See Plates 56, 57, 96. 



Pig-. 1. A small specimen pi-eserving both valves and showing the characteristic ornamentation. 



Hamilton gi-oup. Madison Co., N. T. 

 Fijfs. 2-4. Anterior, posterior and cardinal views of a specimen vertically compressed. 



Hamilton group. Madison Co., N. Y. 

 Figs. 5, 6. Left side and cai-dinal view of a small individual, showing the surface ornaments in a very satis- 

 factory manner. 

 Figs. 7-9. Left, anterior and posterior views of a large specimen which is vertically compressed, making 

 the valves much narrower and deeper than natural. 



Hamilton group. Madison Co., N. Y. 

 Fig. 10. A ft-agment of a left valve pi-eserving the surface ornaments. 



Hamilton g^roup. Shore of Cayuga lake, iV. Y. 

 Pig. 11. An enlargement from the surface of the preceding. 



