CLINTON GROUP. 97 
annulations are scarcely distinguishable, while the thin shell is so closely pressed upon the 
siphuncle that its divisions are distinctly visible. 
Position and locality. In the shale below the ore beds at Wolcott, Wayne county. 
493. 30. ORTHOCERAS ABRUPTUM. 
Pl. XXIX. Fig. 4 a, 6. 
Shell conical, tapering somewhat abruptly; section oval ; siphuncle marginal; septa distant 
about one fourth the narrowest diameter ; surface ? 
The specimen is a fragment of about two inches in length, which tapers abruptly towards 
the apex. The section is oval, though there is no evidence of compression. The position of 
the siphuncle, combined with the conical form, is very characteristic. 
Position and locality. This specimen was sent to me by Col. Jewett of Lockport, as 
coming from the upper limestone of the group at that place. There are some peculiarities 
about it, which incline me to refer it to a higher position ; but at this time I have no means of 
ascertaining positively. ( Collection of Col. Jewett.) 
[ Paleontology — Vol. ii.] 
13 
