Clarke — Oneonta, Ithaca and Portage Gtroups. 



Palseoneilo emarginata, Hall. 

 P. constricta, Conrad (sp. ). 

 P. brevis, Hall. 

 P. fecunda, Hall. 

 P. maxima, Conrad (sp.). 

 Leda diversa, Hall. 

 L. brevirostris, Hall. 

 Paracyclas lirata. Conrad (sp.). 

 Leptodesma Rogersi, Hall, 

 Microdon bellistriatus, Hall. 

 M. gregarins. Hall. 

 Nueula lirata, Conrad (sp.). 

 X. corbuliformis, Hall. 

 Modiomorpha subalata, Conrad (sp.). 

 M. mvtiloides, Conrad (sp.). 

 M. concentrica, Hall. 

 M, sp. nov. 



Modiella pygmaea, Hall. 

 Goniophora rugosa, Conrad (sp.). 

 (t. snbrecta, Hall. 

 (t. Hamiltonensis, Hall. 

 Mytilarca sp. 



Grammysia constricta, Hall. 



(t. magna, Hall. 



(t. elliptica. Hall. 



Gr. bisulcata, Conrad (sp.). 



G. arcnata, Conrad (sp.). 



Sphenomya cnneata, Hall. 



Cimitaria elongata, Conrad (sp). 



Sphenotus contractus, Hall. 



Actinopteria Boydi, Conrad (sp.) 



A. perstrialis, Hall. 



A. zeta, Hall. 



Lunulicardimn ornatum, Hall 



L. fragile. Hall. 



L. laeve, Williams. 



L. many undcscr. species. 



Pholadella, sp. nov. 



Palaeoneilo mnta, Hall. 



Leptodesma sp. 



Ptychopteria mesastrialis, Williams. 



