Chapter M

Length of centrum ·015
Breadth of centrum ·0315
Depth of centrum ·027

Found at Henry's Fork.

Pappichthys symphysis, Cope.

Loc. cit., p. 636.

Found at Cottonwood Creek.

ELASMOBRANCHII.

PLAGIOSTOMATA.

_CARCHARIDÆ._

"Eye with a nictitating membrane. An anal fin; two dorsals."

GALEOCERDO.

Caudal fin with a double notch; mouth crescent shaped; teeth subequal in both jaws, oblique, serrate on both margins.

Galeocerdo falcatus, Ag.

_Corax falcatus_, Poiss. Foss., t. iii., p. 226.

This species is represented by a single tooth from the cretaceous sandstone near the Garden of the Gods, Col. It does not agree exactly with any descriptions or plates which we have seen; but the differences are probably owing to the position or age of the specimen. The crown is low, broad, and not very acute, the edge is finely serrate, and there is no sensible difference between the serrations of the two borders. The anterior border is undulating in outline, but for the most part is convex; the posterior is short and straight, and sends out quite a long heel. One face of the crown is flat and the other is strongly convex. The root is stout and divided into two fangs, which are longer and more distinct than is common in this species. There are no denticles; cementum smooth.

_Measurements._