28 NEW YORK STATE MUSEUM 



PELECYPODA 



MODioLOPSis Hall 

 Modiolopsis aviculoides Hall. Pal. N. Y. 184t:- 1:101 

 Two iiitoiual casts were found in the gray crystalline limestone 

 which are referred with some doubt to Modiolopsis avi- 

 culoides Hall, a little known species with which they agree 

 in the outline of their somewhat ventricose valves, oblique 

 cardinal lines, prominent umbones, and pointed anterior 

 extremity. Hall obtained his specimens from the shaly inter- 

 calated layers in the central part of the Trenton limestone at 

 Middle vi lie. (Oronp 7) 



WHITELLAlJlrich 



Whitella ventricosa Hall sp. 

 E d m o n d i a ventricosa Hall. Pal. N. Y. 1847. 1 :15o 

 A single large sj^ecimen of thie; si)ecies was found in a pebble 

 of black compact limestone. E d m o n d i a ventricosa ife 

 said by Hall to occur in the central and higher part of the Tren- 

 ton limestone at various localities of Xew York. White reports 

 it also from the Black river bed*; of the Poland limekiln section. 

 Hs occurrence in the west is still doubtful. (Group 5) 



CTENODONTA Salter 

 Ctenodonta ? sp. 

 A single cast of a lamellibranch was found on a black compact 

 limestone pebble, which in its outline is suggestive of a Cleido- 

 phorus, but it lacks the preumbonal clavicle impression, and 

 probably belongs to a Ctenodonta of the C. n a s u t a group. It 

 is too incomplete to allow exact determination. (Group 5) 



Ctenodonta vf. astartaeformis Salter 

 There wei-e also found three specimens of a small Ctenodonta 

 of the C. (N u c u 1 a) 1 e v a t a group, which are comparable to 

 C. astartaeformis Salter, of the Canadian Trenton,^ but, 

 judging from the description and figure of that si)ecies, seem to 

 ditfer from that by being wider anteriorly and having very 

 strongly developed growth varices which give to their surface 



I Cad. organic remalna. 1859. Decade 1, p. 39. 



