Fig. 



64. 



65- 

 66. 



67. 



68. 

 69. 



70. 



72. 



Explanation of Plate IX. 

 (Chemung Pelecypoda.) 



Aviculopecten tenuis. Western Chemung. Rare. 

 Aviculopecten duplicates. " " Common. 



Crenipecten crehulatus. " 



Specimen somewhat distorted. 

 Pterinea chemungensis. Eastern Chemung. Common. 



Left valve. See 69. 

 Pterinea reversa. Rare. 



Pterinea chemungensis. Right valve. See 67. 

 Leptodesma potcns. Western Chemung. Common. Left 



valve. 

 Leptodesma potens. Right valve. 

 Leptodesma lielias. Western Chemung. Common. 



Fig. 



73- 

 74- 



75- 

 76. 



77- 



78. 

 79- 



80. 

 81. 

 82. 



83. 



Explanation of Plate X. 

 (Chemung Pelecypoda.) 



Mytilarca chemungensis. Chemung. Common. 



Ply chop leria sp. Common locally in conglomerates and 



closely associated rocks of western N. Y. 

 Sanguinolites undulates. Western Chemung. Rare. 

 Macrodon chemungensis. Eastern 

 Schizodus chemungensis var. quadrangularis. Eastern 



Chemung. Common. 

 Sphenotus contractus. W'estern Chemung. 



Sphenotus clavulus. 4< " 



Generally rare. 

 Edmondia philipi. 



Goniophora chemungensis. Eastern " 

 Paleeoneilo bisulcata. " 



Modiomorpha mytiloides. " 



Rare. Abundant in Hamilton beds. 



Common. 

 " locally 



Rare. 



and 



Portage. 



