400 
PAL2E0NT0L0GY OF NEW-YORK. 
Pholidops squamiiormis (Hall). 
Plate CIII B. Fig. 6 a, b. 
Qrbiculu squamiformis : Report of the Fourth Geological District, 1843, pag. 108, fig. 1. 
— — Palaeontology of New-York, Vol. ii, pa. 250, pi. 93, f. 4 a, b. 
Shell oval or subquadrate oval, very depressed : apex excentric. Surface 
marked by strong concentric lamellae, which are close together on the 
anterior, but wider and diverging on the posterior part of the shell. 
Shell thin, translucent. Fine radiating striae cross the lamellae in well 
preserved specimens. 
Fig, 6 a. Interior of a specimen of the natural size. Fig. 6 6. The same enlarged. 
For the exterior of the shell, see Plate liii, vol. 2. 
Geological position and locality. In the shale of the Niagara group : Lockport, 
Rochester, and Sweden, New-York. 
Pholidops ovatus (n. s,). 
Plate CIII B. Fig. 7 a, b , 
Shell ovate : apex excentric. Surface marked byline concentric lamellae 
of growth, which are wider on the posterior part of the shell. Yery 
minute radiating striae are sometimes visible. 
This shell resembles the Niagara species; but the lamellose strise are finer and 
more closely arranged, and the shell is often proportionally broader. 
Fig. 7 a. Exterior of a speoimen of the natural size. Fig. 7 b. The same enlarged. 
Geological position and locality. In the shalylimestone of theHelderberg group: 
Albany county. 
Pholidops terminalis (n. s ). 
Plate CIII B. Fig. 8 a, b, c, d. 
Shell subelliptical, broader behind, and narrowing to the apex : apex 
terminal. Surface marked by strong squamiform lamellae : a flattened 
sub triangular space beneath the apex; the inner margins of the shell 
