NAPLES FAUNA IN WESTERN NEW YORK, PART 2 3 I 3 



ity short, regularly rounded, subsemicircular, basal margin transverse, poste- 

 rior margin doubly sinuate, postlateral angle obtuse and posterior hinge line 

 oblique and straight. Surface evenly convex over the body of the shell, 

 rising from the beak to about the middle of the valve, sloping broadly to 

 the basal margin and more abruptly in front. Posteriorly two furrows begin 

 near the beaks and widen outward, emarginating the periphery. These are 

 separated by a sharp ridge. Between the outer of these furrows and the 

 cardinal margin there is an abruptly sloping and distinctly sinused area 

 which is in effect a third furrow. On the interior the muscular scars are 

 hardly visible. The cardinal line is not regularly arched as in P. petila 

 but on its inner curvature reaches an apex from which the anterior margin 

 curves inward. The posterior row of denticles is long, the denticles being 

 chevron-shaped, growing small toward the beak till over the narrowest 

 part of the area just behind the beak they are minute. Beneath the beak 

 they turn at an oblique angle (not so acutely as in P. f e c u n d a as rep- 

 resented by Hall '), and pass thence into the short anterior branch, which 

 carries only a few large denticulations. The ornament consists of simple, 

 distant and elevated lamellar concentric lines, which are specially extended 

 on the ridges bounding and dividing the posterior grooves. 



Dimensions. Length 7 mm, hight 4 mm. 



Habitat. Genesee province ; Naples subprovince. In the shales about 

 Naples and Honeoye lake and as barite replacements in the concretions at 

 Whetstone gully, Livingston co. 



Palaeoneilo brevicula sp. nov. 



Plate 15, fig. 16 



Shell small, subtrigonal, length and hight equal, basal margin deeply 

 convex with well marked constriction toward the posterior extremity. 

 Cardinal area subacutely arched, umbonal angle about 90 . Beaks nearly 

 median, anterior slope oblique and direct, curving narrowly to the broad 

 margin. Posterior slope somewhat longer than the anterior. Surface 



'Pal. N. Y. v. 5, pt 1, 2, pi. 49, fig. 22. 



