2 4 



Explanation of Plate XI. 



(Chemung Cephalopoda, Gastropoda, and Braehiopoda. ) 



Fig. 



84. Orl/wceras sp. Common in both Chemung and Portage 



rocks. 



85. Loxonema terebi^a. Eastern Chemung. Locally common. 



86. Eiwmphalus hecale. Western New York. Chemung con- 



glomerates and associated rocks. — After Hall. 



87. Spirifer disjunctus. East and west Chemung. The most 



characteristic and abundant Chemung fossil. Opposite 

 valve similar except with medial fold in place of sinus. 



88. Spirz/er disjunctus. Internal cast of same valve as repre- 



sented by fig. 87. 



89. Spirifer mesacostalis. Same species as fig.- 40. Showing 



extreme cardinal cuspidation. East Portage, east and 

 west Chemung. 



90. Camarotcechia contracta. East and west Chemung. Com- 



mon. Brachial valve. 



91. Same species as fig. 90; pedicle valve, deeply imbedded in 



rock. 



92. Camarotoechia orbicularis. Western Chemung. Rare. 



93- 



94. " duplicata. Both valves. Western Chemung. 



95. " allegania. Western N. Y. Sandstone just 

 below Olean conglomerate. 



96. Tropidoleptus carinatus. East Portage and east Chemung. 



97. Athyris angelica, somewhat decorticated. Western Che- 



mung. Common. 



98. Athyris polita, internal cast. West Chemung. Rare — 



common. 



99. Athyris angelica, perfect, with very fine radiating striae. 



