164 NEW YORK STATE MUSEUM 



Cryptonella (?) fausta Clarke 



Plate 25, figures 5-7 



Cryptonella (?) fausta Clarke. N. Y. State Mus. Mem. 3. 1900. p. 38, 

 pi. 5, fig. 1-8 



Specimens which vary in outHne from the original of this species only 

 in the somewhat greater breadth of the pallial region occur occasionally. 

 None show the brachial structure and hence the generic character remains 

 uncertain. 



Localities. C. ? fausta is known from the Oriskany of Becraft 

 mountain and from Grande Greve and Indian Cove. It has not been 

 observed in the deposits at Glenerie, N. Y. 



Rensselaeria ovoides Eaton (sp.) var. gaspensis nov. 



Plate 25, figures ii 23 ; plate 26, figures 1-5 ^ 



Rensselaeria ovoides Billings. Logan's Geology of Canada. 1863. p. 

 Rensselaeria ovoides Billings. Palaeozoic Fossils. 1874. v. 2, pt i, p. 41, 

 pi. 3, fig. 7, a, b, 10, a 



Mr Billings identified, without qualification or comment, this abundant 

 and peculiar shell with Rensselaeria ovoides Eaton, describing it 

 as follows : 



The usual form of the larger specimens of this species is elongate ovate; sides nearly 

 straight or gently convex as shown in fig. 7, 7a. The smaller individuals (fig. 10, loa) 

 are always wider in proportion to the length and more pointed in front than the larger. In 

 the proportions, there is a gradual passage from specimens in which the width is equal to 

 the length, or even a little greater, to those which the length is twice the width. The 

 ventral valve is the most convex of the two, usually obscurely rounded, angular along the 

 middle, with a gently convex slope towards the sides; a portion of the margin bent at 

 nearly a right angle towards the opposite valve. The outline on a side view is most 

 elevated about the mid-length or a little above; abruptly curved down over the umbo to 

 the l)eak, more gently and uniformly arched to the front margin. Umbo moderate, rising 

 one or two lines above that of the opposite valve; beak closely incurved down to and in 

 contact with the dorsal umbo. The depth of this valve is sometimes nearly equal to its 

 width. Dorsal valve moderately convex, most elevated along the median line where it is 

 rounded angular, with a gentle convex, flat, or even slightly concave, slope towards the 

 sides; a portion of the margin bent at nearly a right angle, as in the ventral valve. The 

 umbo is only slightly prominent, the beak always concealed beneath the opposite beak. 



In the young individuals, the angulation along the median line of both valves usually 

 extends to the front margin; but, as the shell becomes larger, the anterior half or two 

 thirds becomes uniformly depressed, convex, and the angulation disappears. 



Surface with fine radiating striae, five to ten in the width of two lines. These striae 

 are most distinct at the front margin, and become obscure or die out altogether above the 

 mid-length of the shell. Sometimes the upper one third of the shell is quite smooth. The 

 shell is also marked by a variable number of concentric wrinkles of growth, which give the 

 outlines of the shell at all ages, and show how the same individual gradually changed 

 from the broad to the narrow form as it increased in size. In general the specimens from 

 the limestone are smoother than those from the sa-ndstone. 



