456 
PALAEONTOLOGY OF NEW-YORK. 
figured have a length of three inches, and I have fragments of others which have 
been much larger. 
The geological range of the genus, as at present known, is from the upper part of 
the Lower Helderberg group, through the Oriskany sandstone, and into the Upper 
Helderberg limestones. 
In its geographical range , it is known from Gaspe in Canada East, to Virginia and 
Tennessee (and probably occurs in Alabama), and westerly from New-York through 
Canada West, Mackinac island, Ohio, Illinois and Missouri. 
Kenssetaia ovoides. 
Plate CIV. Fio. 1-4; and Plate CV. Fig.1 - 6. 
Meganteris ovoides : IIall, Regents’Report for 185G, p. 102; Palaeozoic Fossils, 1857, p. 62. 
Terebratula ovoides : Eaton, Geological Textbook, 1832, p. 45. ( Not Sowerby, 1812.) 
T. perovalis : Eaton, lb. id. ( Not Sowerby, 1825.) 
Jltrypa elongata : Conrad, Annual Report on the Palaeontology of New-York, 1839, p. 65. 
Not Pentamerus elongatus of the Onondaga limestone, Vanuxem, Geol. Report, 1842, p. 132, f. 1. 
Atrypa elongata : Vanuxem, Mather and Hall, Geol. Reports, 1843. 
Shell ovoid, elongate-ovate or elliptical-ovate in outline, gibbous or 
compressed, broadest above the middle, abruptly rounded towards the 
cardinal end, narrowing to the front, which is often depressed and 
rounded or subtruncate : no traces of a sinus in either valve. In gib¬ 
bous specimens, the edges of the valves are incurved, and the sides 
vertically flattened or a little concave, often slightly contracted near 
the front. Ventral valve the larger, most gibbous in the umbonial region: 
beak (in old specimens) somewhat obtuse, clearly incurved upon the 
opposite. Dorsal valve convex, less elevated than the other, most pro¬ 
minent along the middle or a little above it, forming a low semielliptical 
arch from beak to front, sloping very gradually to the sides, which (in 
old specimens) are often so abruptly inflected as to form a distinct 
angular ridge extending from near the beak two-thirds of the way to 
the front : beak obtuse, scarcely incurved. 
Surface marked by regular simple radiating strife, sometimes crossed 
near the borders by distinct concentric wrinkles : structure punctate. 
