182 PALEONTOLOGY OF NEW YORK. 



Pholidops calceola, sp. nov. 



PLATE IV I, FIG. 30, 



Shell small. Outline subelliptical, the posterior margin being narrowed by 

 the extension of the beak, which is long and acute, slightly elevated above 

 the plane of the margin. External surface marked by concentric lamellose 

 growth-lines, which extend about the posterior side of the beak. Muscular 

 area central ; posterior margin divided into a broad central and two lateral 

 arches, from the latter the outline extending in a regular curve to the ante- 

 rior margin. Adductor scars sharply defined. The dorsal (?) valve only is 

 known. Length of the original specimen, 3.5 mm. 



Corniferous limestone. Falls of the Ohio. 



Pholidops patina, sp. nov. 



PLATE IV I, FIGS. 27-29. 



Shell comparatively large ; outline elongate-ovate or elliptical. Length to 

 width as 3 to 4. Apex posterior. Surface covered with lamellose con- 

 centric' growth-lines, which are crossed by fine, interrupted radiating striae. 

 The interior of the ventral (?) valve has the anterior and posterior adductors 

 well defined, the latter being lobate. The median scars are well developed 

 and the parietal impression acutely angled at the center. In the opposite 

 valve the anterior edges of the muscular area are sharply elevated, both pairs 

 of adductor scars prominent, and the parietal scar extended posteriorly. 



Corniferous limestone ; from boulders of decomposed chert. De Cewville, 

 Ontario. 



