TRENTON LIMESTONE. 
187 
the shell, the detail of the surface markings is partially lost, and a broad dorsal carina is 
sometimes all that is observable ; the marginal carinae are often faintly distinguishable by 
a slight depression on either side. A section below the aperture presents an extremely 
excentric ellipse, which is depressed on the ventral side by the convexity of the contiguous 
volution. 
Fig. 8 a. Dorsal view of a small specimen, preserving a portion of the shell. 
Fig. 8 b. View of the aperture, which is very imperfect. 
Fig. 8 c. A fragment, showing the carinac and dorsal band very distinctly, d. The same enlarged. 
Fig. 8 e. Cast of a larger specimen, imperfect towards the aperture, and showing only the broad dorsal 
carina. /. Lateral view of the same, showing the umbilicus. 
Fig. 8 g. Section of the last volution below the aperture. 
Position and locality. This species occurs in the lower shaly portions of the rock at 
Middleville, and in the compact lower layers of the same rock, immediately above the 
Black-river limestone, at Watertown, Jefferson county. {State Collection.) 
245. 5. BUCANTA PUNCTIFRONS. 
Pl. XL. A. Figs. 1 a, b, c, d, e. 
Bellerophon punctifrons. Emmons, Geol. Report, 1842, pag. 392, fig. 5. 
Convolute, suborbicular ; volutions about three, gradually enlarging, rounded upon the 
back ; dorsal line marked by an abrupt narrow carinal band ; sides of the volutions 
abruptly rounded, suddenly depressed into a broad deep umbilicus, which reveals the 
inner volutions ; surface marked by rounded or rhomboidal punctures, which are regularly 
arranged in lines in two directions ; carinal band marked by close curved strife ; the last 
volution is little extended, and abruptly expanded near the aperture, which has a shallow 
sinus on the dorsal margin. 
This beautiful species is readily distinguished by the peculiarly ornamented surface. The 
dorsal band is sometimes abruptly elevated, and at other times even with the surface of 
the shell, and marked by curved strife. In a single specimen I have detected lateral 
longitudinal ridges, which interrupt the regularity of the surface markings ; but these 
appear to be accidental. 
Fig- 1 a. Dorsal view of a small specimen, b. Lateral view, showing the umbilicus. 
Fig. 1 c. Dorsal view of a larger specimen, showing the elevated carinal band, which does not rise 
above the surface on the lower part of the shell. 
Fig. 1 d. Lateral view of another specimen, showing the side of the shell, which is obtusely angular 
with obscure longitudinal ridges. 
O O 
Fig. 1 e. A portion of the surface enlarged. 
Position and locality. This species occurs in the higher crystalline portions of the rock 
at Middleville and Watertown. (State Collection.) 
24 
