334 
PALEONTOLOGY OF NEW YORK. 
It is proportionally much higher than P. plana and smaller and more constricted 
than P. maxima. 
Formations and localities. In the shales of the Hamilton group, Fultonham 
and Bear’s gulf, Schoharie county; shores of Seneca and Cayuga lakes, N. Y., 
and Patterson’s creek, Ya.; in the Portage group, at Portland Harbor, Chautau¬ 
qua county, and in the lower Chemung or Ithaca group, at Ithaca, N. Y. 
Pal.eoneilo constricta, var. flexuosa. 
PLATE XLVIII, FIGS. 17-20. 
Palceoneilo constricta (Conrad sp.), var. flexuosa, Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations : 
PL 48, tigs. 16-20 (16 in error). 1883. 
Specimens having the general aspect of P. constricta occur in the Chemung 
group, at Ithaca. The shell is stronger, more elongate in form, more coarsely 
and irregularly striated with the constriction at the posterior end strongly 
marked. 
Formation and locality. In the lower part of the Chemung group, at Ithaca, 
N. Y. 
Palceoneilo plana. 
PLATE XLVIII, FIGS. 21-28. 
PalcBoneilo plana, Hall. Prelim. Notice Lamellibranchiata, 2, p. 7. 1870. 
“ “ “ Pal. N. Y., vol. 5, pt. 1. Plates and Explanations : PI. 48, figs. 21-28. 1883. 
Shell below the medium size, transversely elliptical, compressed, elongate and 
somewhat pointed behind; length almost twice the height; basal margin 
regularly and gently rounded, with a slight and undefined constriction near 
the posterior end. Posterior extremity acutely rounded. Cardinal line 
declining on each side of the beak. Anterior end regularly rounded. 
Yalves depressed-convex. 
Beaks anterior to the centre, small, rising but little above the hinge-line. 
Umbonal slope not defined, obscurely indicated by an undefined depression, 
which scarcely constricts the margin. 
Surface marked by very fine concentric striae, which are often obscure or 
obsolete. Interior as shown in figs. 25, 26 of plate xlviii. 
Several specimens have a length of 15 mm. and a height of 8 mm. 
