302 
PALEONTOLOGY OF NEW YORK. 
Beaks situated less than one-third the length of the shell from the anterior 
end, closely incurved. Umbo prominent. Umbonal slope distinctly carinated 
and terminating at the basal extremity. 
Test of moderate thickness, marked by fine undulating concentric strim, 
which are aggregated into folds upon the lower and anterior part of the shell. 
On the cardinal slope these undulations are less prominent. Interior unknown. 
Four specimens have the following dimensions respectively: Length 70, 
63, 35 and 16 mm.; height 28, 26, 16 and 7 mm. 
This species is comparatively longer than G. Hamiltonensis and G. rugosa, and 
the concentric striae are finer and strongly fasciculate, while the anterior end 
is much longer. Compared with G. Chemungensis , the beaks are more distant 
from the anterior end, the umbonal ridge is slightly curved, while in that 
species it is very rigid; the posterior extremity is wider. 
Formation and localities. In the shales of the Hamilton group, associated with 
Paracijclas liraia, Chonetes scitula, Spirifera mucronata, and Hyolithes aclis, at Cop¬ 
ley’s quarry, Oneonta, and near Mount Upton, N. Y. 
Goniophora trigona, n. sp. 
PLATE XLII, FIG. 12; AND PLATE XLIV, FIG. 9. 
Goniophora glabra, Hall (error for G. Glaucus). Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 
44, tig. 9. 1883. 
Shell large, trapezoidal; body sub-trigonal; length twice the height; basal 
margin sinuate anterior to the middle, curving gently toward the post-basal 
extremity and more rapidly to the anterior ; posterior margin obliquely 
truncate; cardinal line short, essentially straight; anterior end large, slop¬ 
ing somewhat abruptly from the umbo and narrowly rounded below, limited 
posteriorly by a broad undefined sinus. Shell convex below, gibbous above ; 
cardinal slope slightly concave, descending abruptly from the umbonal ridge 
and gently rising toward the cardinal line. 
Beaks at about the anterior third; umbo very prominent; umbonal ridge 
