296 
PALAEONTOLOGY OF NEW YORK. 
which are fasciculose on the anterior portion of the shell. Radiating striae 
are obscurely visible on both the specimens figured. On the nmbonal ridge 
the test is raised into a thin crest. Interior unknown. 
The principal specimen described has a length of 80 mm., and a height of 
about 28 mm. 
This species resembles G. Hamiltonensis, but differs in having the beaks nearer 
to the anterior end, in its more elongate form, and in the radiating striae of the 
surface-characters not observed in specimens referred to that species. As com¬ 
pared with G. iruncota , it is a more elongate shell with a proportionally longer 
and less oblique hinge-line. 
Formation and locality. In the soft shales of the Hamilton group, on the 
shores of Canandaigua lake, N. Y. 
Goniophora Hamiltonensis. 
PLATE XLIII, FIGS. 8-15, 17-21. 
/Savguinolites Hamiltonensis, Hall. Prelim. Notice Lamellibranchiata, 2, p. 36. 1870. 
Goniophora Hamiltonensis, Hall. S. A. Miller. Cat. Amer. Pal. Foss., p. 192. 1S77. 
“ “ “ Pal. N. ¥., vol. v, pt, 1. Plates and Explanations: PI. 43, figs. 8-21. 
1883. 
Shell large, trapezoidal ; length more than twice the height; basal margin 
gently curving, sometimes nearly straight and slightly affected by the sinus. 
Posterior margin obliquely truncate. Anterior margin concave below the 
beak and abruptly rounded below. Cardinal line very slightly arcuate, 
extending for two-thirds the length of the shell; margins inflected, forming 
a long, deep escutcheon. 
Valves moderately convex below the umbonal ridge, and concave above it 
to the cardinal line. 
Beaks sub-anterior, small, closely incurved, situated from one-fourth to 
one-sixth the length of the shell from the anterior margin. Umbonal ridge 
angular, strongly defined, arching over the beaks and extending in nearly a 
direct line to the post-basal extremity. Umbonal region scarcely gibbous, 
separated from the anterior end by a broad undefined sinus, which becomes 
obsolete in some specimens, owing to compression. 
