18 
PALEONTOLOGY OF NEW YORK. 
This species resembles A. rugcestriatus in surface characters, but it is less 
oblique and proportionally much longer, with beaks more obtuse. The outline 
of A. cancellatus is more nearly circular, and the direction of the transverse 
axis is oblique. From A. scabridus it differs in its shorter hinge-line and 
smaller ears, as well as in the surface markings. 
Formation and localities. In the calcareous shales of the middle Chemung 
group, Rockville, Hobbieville and Philipsburg, Alleghany county; East Ran¬ 
dolph, Cattaraugus county, N. Y.; and Mansfield and Sullivan, Tioga county, 
Pennsylvania. 
Aviculopecten cancellatus. 
PLATE VII, FIGS. 12,14-19. 
Pecten cancellatus. Hall. Geolog. Surv. N. Y. : Rep. Fourth Dist. 1843. 
Not Aviculopecten cancel latulus, McCoy. 
Pecten Halleanus* d’Oebigny. Prodrome de Palseontologie, jvol. I, p. 87, No. 768. 1847. 
Aviculopecten sub-eancellatus, Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 7, figs. 12, 
14-19. Jan., 1883. 
Shell small, broadly ovate, oblique, height a little greater than the length; 
anterior lateral margin full and rounded; posterior lateral margin, below the 
ears, gently curving. 
Right valve regularly convex, sloping somewhat abruptly to the posterior 
ear. 
Hinge-line straight, equal to two-thirds the length of the shell. 
Beaks, anterior to the middle of the hinge-line, well-defined, obtuse. 
Posterior ear small, undefined, the lateral margin concave, not projecting. 
Anterior ear marked by a deep sinus, with a sulcus extending to the beak; 
lateral margin rounded. 
Test marked by fine, regular, rounded, radiating lines, crossed by regular 
sharp, concentric striae, producing an evenly cancellate surface. The 
posterior ear is marked by the concentric striae with obscure radiating 
lines; the anterior ear is rugose from the prominence of from four to six 
strong rays. 
* This name was proposed by d’Orbigny as a substitute for Pecten cancellatus, a name preoccupied by 
Phillips for an Oolitic fossil. The latter is probably a true Pecten, and there seems to me no sufficient 
reason why the original name may not be retained. Avicula cancellata, Phillips, Palaeozoic Fossils, is 
probably not an Aviculopecten. 
