336 
PALEONTOLOGY OF NEW YORK. 
PaLEONEILO tenuistriata. 
PLATE XLIX, FIGS. 1-T2, 14 ; AND PLATE XCIII, FIG. 13. 
PalcBoneilo tenuistriata ,, Hall. Prelim. Notice Lamellibranchiata, 2. 43 . 9. 1870. 
“ “ “ Pal. N. Y., vol. v, pt. 1. Plates and Explanations : PI. 49, figs. 1-12. 1883. 
Shell large, ovate-elliptical; length more than one-third greater than the 
height; basal margin regularly curving. Posterior end doubly truncate. 
Cardinal line gently arcuate. Anterior end short, rounded. 
Valves convex, gibbous above the middle and in the umbonal region. 
Beaks at about the anterior third, moderately prominent, nearly straight, 
little elevated above the hinge-line. The posterior end of the shell is 
depressed-convex, with a more or less distinct depression extending to the 
post-inferior extremity from just posterior to the beaks, giving a truncation 
and slight constriction of the margin. 
Test thick, especially in the dorsal region. Surface marked by very fine 
concentric strias, which are often crowded together on the basal and poste¬ 
rior portions of the shell, forming irregular undulations of growth. In some 
well-preserved specimens the concentric striae are elevated into sharp lamellae. 
Three specimens measure respectively 29, 33 and 37 mm. in length, and 
18, 19 and 20 mm. in height. 
This species may be distinguished from P. fecunda by its finer and more 
irregular surface striae and usually shorter form. 
Formation and localities. In the soft shales of the Hamilton group, on the 
shores of Skaneateles, Cayuga and Seneca lakes; at Pratt’s falls and Delphi, 
Onondaga county, and York and Moscow, Livingston county, N. Y.; also from 
Patterson’s creek, Va. 
Paleoneilo fecunda. 
PLATE XLIX, FIGS. 13, 15-24. 
Palceoneilo fecunda. Hall. Prelim. Notice Lamellibranchiata, 2, p. 8 . 1870. 
“ “ “ Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 49, figs. 13-24. 1883. 
Shell large, elongate-ovate; length nearly twice the height; basal margin 
broadly curving. Posterior end obtusely rounded or doubly truncate. Car¬ 
dinal line arcuate. Anterior end regularly rounded. 
