NAPLES FAUNA IN WESTERN NEW YORK, PART 2 



399 



13 Two superposed valves. X3 



Naples subprovince 



14 A large right valve. X3 



Genesee shale 



15 A left valve. X2 



Genesee shale 



16 A right valve. X2 



Genesee shale 



Ithaca 

 Aurora, Cayuga lake 



Aurora, Cayuga lake 



Pterochaenia sinuosa sp. nov. 



Page 253 



17 A right valve showing the contour of the surface. X3 

 18, 19 Two views of a left valve. X3 



20, 2 1 Exterior and interior of a right valve with broad sica. X3 

 22 A more elongate right valve with very broad sica. X3 

 Naples subprovince 



Genundewa limestone, Canandaigua lake 



