CORALLINE LIMESTONE. 
337 
703. 4. ONCOCERAS EXPANSUM (n. sp.). 
Pl. LXXVII A. Fig. 2 a, b. 
Shell ventricose, rapidly expanding in the middle; septa closely arranged, very slightly 
convex ; siphuncle subdorsal; surface? 
This fragment, from the rapid expansion towards the aperture, is sufficiently characteristic to 
indicate a distinct species. The fragment consists of about five septa preserved in their natural 
form, though destitute of the shell. 
Fig. 2 a. Lateral view of the specimen. 
Fig. 2 b. Transverse section, showing the position of siphuncle. 
Position and locality. In the Coralline limestone at Schoharie. 
( Collection of John Gebhard junior.) 
In addition to the specimens described above, Mr. Gebhard has recently discovered a spe¬ 
cimen of Trochoceras much more depressed than T. gebhardii , and which may prove distinct 
from that one, though it is impossible to decide from the single imperfect specimen in question. 
He has also discovered an Orthoceras, which may prove characteristic of the mass ; though 
from the fragment in my possession, I am unable to describe it with sufficient accuracy to be 
made available. 
The Coralline limestone exists in place at several localities on the east side of the Helderberg, 
but I have had no opportuity of examining these places in' detail. It is not improbable that 
many more species may be added to those already known. 
/ 
CRUSTACEA OF THE CORALLINE LIMESTONE. 
The Crustacea known in this rock, consist of a single species, of trilobite, and a single 
species of Cytherina. . 
704. 8. CALYMENE CAMERATA. 
Pl. LXXVIII. Fig. 1 a -/. 
Calymene camerata. Conrad, Jour. Acad. Nat. Sci. Philadelphia, Yol. viii, p. 278, 1842. 
Cephalic shield wide, subcrescent-form; anterior margin elevated in a strong fold, a deep 
groove separating it from the front of the glabella and cheeks ; glabella broader and nearly 
straight in front, furnished on each side with three distinct tubercles, the posterior one very 
large and prominent, the anterior one minute; eyes opposite to the central lobe of glabella; 
the furrow between the glabella and cheeks very deep ; a projecting lobe from behind the eye 
touches or unites with the middle of the three lobes of the glabella, and a similar projecting 
