268 NEW YORK STATE MUSEUM 



Habitat. Genesee province ; Chautauqua subprovince. In the soft 

 shales at Varysburg (west side ravine) and common at Johnson's falls near 

 Strykersville, Wyoming co., Correll's point, Lake Erie, and at the Hidi 

 tannery, Gowanda. 



Observations. The oblique, Leptodesmalike form of this peculiar 

 species suggests the elongate varietyof Posidonia venusta Miinster 

 which Freeh has termed eifeliensis 1 from the uppermost Devonic near 

 Budesheim. Both are essentially smooth shells, highly oblique with short 

 hinge and sharp cardinal angles. Freeh mentions a very fine radial 

 lineation in his shells. 



Posidonia venusta Miinster, var. nitidula sp. nov. 



Plate 12, fig. 16-19 

 cf. Posidonomya? venusta Miinster, Beitr. zur. Petrefakten-Kunde. 1840, 3:51, pi. 10, fig. 12 



Shells small, equivalve. Ligament line straight, length four fifths the 

 greatest length of the valve. Beak at anterior third of cardinal line ; car- 

 dinal extremities subangular, not extended. Outline of periphery obliquely 

 ovate, expanded behind, contracting toward the hinge angles both front 

 and back. Surface convex; at the umbones the convexity extends obliquely 

 backward to the posterior extremity. In front of this convexity is a low 

 oblique depression, which gives a sinuous character to both surface and 

 basal margin. Posterior slope from umbonal ridge broadly depressed. 

 The ornament consists of a few broad concentric corrugations with no 

 radial lines visible. 



Dimensions. An average specimen has a hight and a length of 9 mm. 



Habitat. Genesee province; Chautauqua subprovince. In the soft 

 shales at Gowanda, Cattaraugus co. (Hidi tannery), and Correll's point, 

 Lake Erie. 



Observations. This quite well defined little shell is in general expres- 

 sions so like the Posidonia venusta Miinster which is distributed 

 through the Lower, Middle and Upper Devonic of Germany that I believe 



J 0/>. cit. p. 76, pi. 14, fig. 14. 



