HAMILTON GROUP. 
197 
3. Cucullea opima, n. s. — Ovate, very convex; beaks near the anterior extremity, very 
prominent; surface marked by strong concentric lines ; cast nearly smooth; impression of 
the internal laminae oblique. 
When compressed, this fossil has the appearance of a Nucula; but the impressions of the 
internal laminae seem sufficient to warrant its reference to Cucullea. 
Locality —Ovid, Seneca county. 
4. Nucula? oblonga. — Oblong, elliptical, very inequilateral, very finely and concentrically 
striated; an impressed line extends from the hinge, just forward of the beak, half way to the 
base. 
This is a very common form in the eastern part of the district. 
Localities —Cayuga and Seneca lake ; Outlet of Crooked lake ; Genesee valley. 
5. Nucula lineata? (Phillips, Paleozoic Fossils, p. 39, fig. 64).— Sub-triangular, con¬ 
vex ; beaks much elevated ; surface covered with coarse concentric strias. 
This shell is not very uncommon in the ravines about Seneca and Cayuga lakes, though the 
specimens usually seen are much compressed and distorted. 
Locality —Seneca lake shore ; Shelldrake point on Cayuga lake. 
6. Tellina? ovata, n. s. — General form ovate, produced posteriorly, and apparently slight¬ 
ly gaping at the extremity ; posterior slope angulated ; surface covered by minute concentric 
striae, which become more prominent near the margin. 
Since no teeth are visible in the hinge line, and the external form is so analogous to Tellina , 
it is referred to that genus. 
Locality —Cayuga lake. 
7. Nucula bellatula, n. s. — Ovate, somewhat contracted near the posterior extremity; 
surface covered with regular, fine concentric striae ; teeth in the hinge margin very distinct. 
There is a slight depression extending along the posterior slope, giving a contracted appearance 
to this part of the shell. 
This beautiful little shell is often seen in the harder shales of the group. 
Localities —Cayuga and Seneca lakes. 
8. Cypricardia truncata. (Cypricardites truncata, Conrad, Jour. Acad. Nat. Sci. Vol. 
8, p. 244, pi. 12, fig. 17.)—Trapezoidal; surface covered with concentric wrinkles ; pos¬ 
terior slope sharply carinated. The wrinkles upon the posterior slope are parallel to the 
truncated margin, and nearly at right angles with those upon the side of the shell. 
Compare Cucullea arguta (Phil. Geol. Yorkshire, Part ii, pi. 5, fig. 20). 
Locality —Cayuga lake. 
9. Modiola concentrica. — Oblong-ovate, very inequilateral; surface covered with regular, 
equal concentric striae, which become confluent towards the base ; hinge line curved; anterior 
side short, with a longitudinal impression directly below the beaks. 
