TRENTON LIMESTONE. 
171 
220. 3. HOLOPEA PALUDINIFORMIS. 
Pl. XXXVII. Figs. 3 a, b. 
Pleurotomaria. Emmons, Geol. Report, 1842, pag. 397, fig. 1. 
Spiral, scarcely oblique, elevated ; height greater than the breadth ; volutions four or 
more, rounded, ventricose, enlarging somewhat rapidly from the apex ; aperture round 
ovate ; surface? The specimen is a cast, preserving no surface markings. 
This species resembles the first described, but it is comparatively more gibbous, and the 
spire less elevated in proportion to the size of the shell. In form and aperture, it closely 
resembles the larger Paludinje. 
Fig. 3 a. Vieiv of the back of the shell, b. View of the aperture. 
Position and locality. The only specimen known, is from (he crystalline upper part of the 
Trenton limestone at Watertown, Jefferson county. {State Collection.) 
221. 4. IIOLOPEA VENTRICOSA (n.sp.). 
Pl. XXXVII. Figs. 4 «, b. 
Spiral, oblique, subglobose, very ventricose ; height and breadth nearly equal ; spire 
short; volutions about three, rounded, rapidly enlarging from the apex, and becoming 
ventricose ; aperture rounded oval, slightly contracting at the upper side ; surface? 
The specimen is a cast, preserving some slight evidences of striae as in fig. 1, which 
appears to have been the prevailing character of the markings on the surface. But few 
specimens of either of the species have been seen, and they are much more rare than (he 
Pleurotomaria, and occur almost entirely or altogether in the upper part of the rock. 
Fig. 4 a. View of the back of the spire, b. View of the lop of the spire. 
Position and locality. In the upper crystalline part of the Trenton limestone at Middle- 
ville, Herkimer county. 
Several other imperfect specimens, apparently referable to this genus, have been observed 
in the Trenton limestone, but none of them in a condition to furnish specific characters. 
There are smooth casts of Pleurotomaria, resembling in general form these or smaller 
species of the same genus, being sometimes regularly rounded ; but in most instances they 
preserve some evidence of the angular form of the last volution, which is never seen in the 
Holopea. 
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