PLATE LVIII. 



(IkAMMYSIA ELLll'TICA. 



I'ajfc sue. 

 Pig. 1. A Hiiiall left valve of umisiially i-otuiiil form, i-efeiTcd to this species with some doubt. 



Lower Chemung gi-oup. Ithaca, N. Y. 

 Fig. 2. A left valve of the usual form and proportions. 



Chemung group Alleghany Co., N. Y. 

 Fig. 3. A right valve similar to the pi-eceding. 



Chemung group. Philipsburgh, N. Y. 

 Fig. 4. A right valve. 



Lower Chemung gi-oup. Ithaca, N. Y. 

 Fig. 5. A left valve similar in fomi to fig. 1, and also referi-ed with doubt to this sjiecies. 

 Pig. 6. The opposil* side of the pi-eceding, showing the escutcheon and hinge. 



Chemung group. Philipsburgh, N. Y. 

 Fig. 7. The left side of a sj>ecimen. 



Chemung group. Maiutfifld, Pa. 

 Figs. 8, 9. Two left valves of young indiviiluals. 



Chemung group. Philipsburgh, N. Y. 

 Fig. 10. A large right valve. 



Chemung group. Manafield, Pa. 

 Fig. 11. The anterior portion of a large right valve of unusually erect fiirni. 



Chemung group. Mansfield, Pa. 

 Fig. 12. The hinge of a right valve showing the ligamental area and cardinal fold. 



Chemung group. Mansfield, Pa. 



GkAMMYSIA CIECULARI8. 



Pa^e 364. 



See Plate 57. 



Fig. 13. The left side of alai-ge individual. The sjiecimen was found in the town of Nichols, Tioga Co., 



N. Y. Its precise horizon is unknown. 



