PLATE LXUI. 

 Gkammvsia |{i:lla tl i.a. 



Page 367. 

 Kig. 1. A small bliMik of shale j)ri;«iTviiig- two valves, pi-obtiVily of the same indivicUial. 



Haiiiiltdii jri'oiip. York Center, LUHuysUm Co., N. Y. 

 Figs. 2, 3. The two valves eulai-g-ed. 



GkAMMV.>5IA ZONATA. 

 rage sn. 

 Pig. 4. A left valve, enlwged. 



Hamilton fj-roup. Sthoharie Co., N. Y. 

 Fig 5. A specimen i-etainin(r both valve« in conjimction. In the left valve the lidge on the uniboiial 

 slope is due to a fi-iicture and exaggerated in the figure 



GkAMMYSIA AK( I ATA ? 



Page 373. 



See Plate-s 61, 93. 



Fig. 6. The left valve of a caHt of the interior. The ridge on the unibonal slope is probably due to a 

 fra<;ture in the shell. 



Hamilton group. Eighteen Mile creek, N. Y. 



Gram-mysia EUIOPIA. 



Pago 368. 

 Fig. 7. A right valve. The umbo M represented as too nari-ow in the fif.'-iire, and the aj)pai-ent furrow on 

 the post-cai-dinal sIhjm; is a gentle fold. 



Hamilton grou]). Shore of Seneca lake, N. Y. 

 Fig. 8 A large right valve. 



Hamilton group. Sliore of Canandnigua lake, N. Y. 



Ed.MOMJIA ? TKNUISTUIATA. 

 Page 893. 



See Plate 93. 

 Fig. 9. An imperfect right valve. jaBj^i^j 



Chemung group. Near Elviira, N. Y. ^^B; 

 Fig. 10. An enlargement of the surface showing the concentric lines of growth and radiating strije. 



