OF DENISON UNIVERSITY. 
99 
GENUS BUCANIA, Hall. 
VIII. BuCANIA EXIGUA, sp. 11 . 
{Plate XIII, Figs, a, b, 
Number of volutions not known, the last alone visible, increasing 
rapidly in size and expanding at the aperture; the exact character of 
the aperture not known from want of preservation, but is presumed to 
be similar to that of B. bilobatiis. The outer volution rounded on the 
dorsum at its origin, a mesial carina gradually developing toward the 
aperture near which it becomes quite distinct, in some individuals, de- 
cidedly so. From this carina the sides slope evenly to the umbili- 
cus, which they enter with a sudden curve, forming a low, indistinct, 
lateral carina, by the increase of curvature. Umbilicus apparently 
closed, the last volution alone being visible in the specimens examined. 
Surface of the cast smooth, traces of the original shell, however, seem 
to remain in a few spots, indicating a system of striae curving from the 
mesial carina obliquely backwards, these apparently crossed by other 
striations. The usual form of the cast, however, is smooth, the shell 
being entirely removed. 
Measurements, on account of the imperfect preservation of the shell 
towards the aperture, are of little value, still the following will serve to 
give a general idea of the proportions of the shell. Greatest diame- 
ter of the typical specimen (Plate XIII, Figs, a, b. ), 9 mm.; diameter 
at right angles to this, 6.2 mm.; diameter of last volution at the 
point where it becomes visible, 3.5 mm.; broadest part of volution 
preserved, 7 mm. From this they vary in size from specimens which 
become almost minute to some having a greatest diameter of 22 mm. 
locality and position. Beavertown marl, Huffman’s Quarry, Clin- 
ton Group. (Name quite small.) 
GENUS BELLEROPHON, Montfort. 
IX. BeLLEROPHON FISCELLO-S'FRIATUS, sp. 11. 
{Plate XIII, Figs. 19 b, c, d.) 
Shell sub-discoid ; only the last volution known, increasing rapidly 
in size, being almost four times as large at the aperture as at the point 
where it first becomes visible ; the increase in size is quite regular, ex- 
cept near the aperture where there is a moderate expansion of the vo- 
