218 
PALEONTOLOGY OF NEW YORK. 
of their sculpture, which consists of fine incised lines separated by broad, re- 
trally sloping annulations. Tliis ornamentation is noticeably coarser than in 
any of the associated species. 
Their size varies from a length and width of 4 mm. to a length of 6 mm. 
and a width of 5 mm. 
Distribution. Hamilton group Centerfield and Canandaigua, Ontario county. 
Turrilepas nitidulus, n. sp. 
PEATE XXXVI, FIG. 4. 
A SINGLE plate wanting the nuclear portion is distinguished from the asso¬ 
ciated forms by its very fine and closely set concentric strim, and its broad 
posterior area, which is covered with conspicuous pits or punctse, apparently 
arranged also in concentric lines. The basal margin is gently sinuous, corres¬ 
ponding with the sinuous concentric lines, and a broad low sinus is apparent 
over the median portion of the valve. 
The length of the specimen is 2.5 mm., and the height about 2 mm. 
Distribution. Hamilton group. In the lower shales at Fall Brook, Hopewell, 
Ontario county. 
Turrilepas foliates, n. sp. 
PLATE XXXVI, FIG. 15. 
A SINGLE plate has an elongate semi-lanceolate or semi-saggitate outline, and 
a length equal to three times the height. The nucleus is not distinctly seen in 
the specimen, and the concentric lines in its vicinity appear to be obsolete, but 
further downward are closely crowded and clearly defined. The posterior 
margin is long and straight, appears to have been slightly elevated or thickened 
and possibly folded. The anterior margin seems to have been abrupty curved 
across the plate, rounding backward to the straight basal margin. 
The height of the plate is 2.6 mm., its length 7 mm., and the distance along 
the posterior margin 9 mm. 
Distribution. Hamilton group. In the limestone layers at the base of the 
Hamilton shales: Canandaigua, Ontario county. 
