2*> 



Explanation of Plate IX. 

 (Chemung Pelecypoda.) 



Fig, 



64. Aviculopcctai tenuis. Western Chemung. Rare. 



65. Aviculopechn duplicatus. lk lk Common. 



66. Crenipccten crenulahis* *' " 



Specimen somewhat distorted. 



67. Pterinca chcmungensis. Eastern Chemung. Common. 



Left valve. See 69. 



68. Pterinca reversa. ' 4 " Rare. 



69. Pterinca chcmungensis. Right valve. See 67. 



70. Leptodcsmp patens. Western Chemung. Common. Left 



valve. 



71. Leptodcsma patens. Right valve. 



72. Leptodcsma lic/ias. Western Chemung. Common. 



Explanation of Plate X. 

 (Chemung Pelecypoda.) 



73. Mytilarca chcmungensis. Chemung. Common. 



74. Ptychopieria sp. Common locally* in conglomerates and 



closely associated rocks of western N. Y. 



75. Sanguhwlites ttndulatus. Western Chemung. Rare. 



76. Macrodo?z chcmungensis. Eastern " " 



77. Schizodus chcmungensis var. quadrangularis. Eastern 



Chemung. Common, 



78. Sphcnotus contractus. Western Chemung. Common. 



79. Sphenoius clavuhis. " " 4< locally. 



Generally rare. » 



80. Edmondia philipi. " " *' 



81. Goniophom chemungensis. Eastern " Rare. 



82. Palceoneilo bistdcat®, " " " 



S3. Modiomorphamytiloidcs. lt *' and Portage. 



Rare. Abundant in Hamilton beds. 



