PLATE L. 

 Pal^eoneilo emarginata. 



•. ■; .^-^. Page 338. 



Figs. 1-6. A series of right valves showing- the gradations in size and the prevailing oharactei-s of the 

 species. 



Hamilton group. Onondaga, Cayuga and Schoharie Co's, N. Y. 



Figs. 7-10. A series of left valves. i > i / >-i 



Hamilton group, i. ,/. i /:\ I I /. iKllA/' :i.'./ ' \ 

 Fig. 11. A right valve of a small individual enlarged to two diametei"8. 

 ' Lower Chemnng group. Ithaca, N. Y. 



Pal^oneilo BISULCATA. 



I'age 344. 



Figs. 12-14. A right and two left valves enlarged to two <liameter8. 

 Chemung group. Near Elmira, NT. ' 



PaL.A;0.\E1L0 PERPLiiNA. 



I'age 339. 

 See Plate 93. 

 Figs. 15-18. A series of left valves, sho\yi)ig gradation in size and vai-iation in form. 



Fig. 19. An enlargement of the left valve of an individual with the umbo cut away, showing the crenulated 

 hinge. 



Hamilton group. Ludhrwville, N. Y.'" 

 Fig. 20. A specimen retaining the two valves in conjunction. 



Hamilton gi-oup. liear'sgidf, tichoharle Co., N. Y. 

 Fig. 21. A large right valve. 



Hamilton group. Bear's gv,lf, Schoharie Co., N. Y. 

 Fig. 22. A specimen retaining both valves in conjauction. 



Hamilton groiij). Btnr'fi gutf, SchoTinrif C"., N. Y. 



Pai..eoneilo auata. 



I'atrc m. 

 Fig. 23. The right side of a specimen retaining the two valves in conjunction. 

 Hamilton gi-oup. 'Near Norwich, Chenaiiip Co., N. Y. 



P.iL.EOXlrtLd iltEVI.S. *■ ' ■''■* 



rage 342. 

 Figs. 24-30. Natural ca-sts of the interior of right and left valves, presenting the general form of the fossils 

 and showiTig the anterior muscidar scai\ 



Chemung grouj). Franklin, Delaware Co., N. Y. ' Fig. 30 from Philipsbwrgh, N. Y. 

 Fig. 31. A specimen pi-eservang the surface markings. 



Chemung group. Philipuhurgh, N. Y. 

 Fig. 32. A small specimen preserving the surface mai-kiiigs and showing the crenulations of the hinge. 



Chemung group. Phili-pKbnrgh, N. Y. 

 Fig. 33. A cast of a right valve showing mu.scular sc'ars. 



Chemung group. Franklin, Delaware Co., N. Y. 



:'P5i;S 



