Ray and Skate Fossils
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|Figs. 1a, 1b. Squatina occidentals n. sp.|
1) Outer face of tooth (type specimen) showing downward prolongation of the enamel below the base of crown. Plum Point.
1b) Inner face of the same specimen.
|Fig. 2. Raja (?) dux Cope.|
|2) Superior aspect of a detached and considerably abraded dermal tubercle. (Type specimen.) Charles County near the Patuxent River. Acad. Nat. Sci., Phila.|
|Figs. 3a, 3b. Myliobatus gigas Cope.|
| 3a) Oral surface of the upper dental pavement
of an adult individual, the anterior end (shown uppermost in the figure)
fractured and imperfect.
(Type specimen.) Charles County near the Patuxent River. Acad. Nat. Sci., Phila,
3b) Transverse view of the same specimen, taken across its posterior
A single characteristic tooth of the "Angel-fish," Squatina, without lateral denticles and having a small median downward prolongation of the crown upon the front of the root below the large cone, was obtained by the Survey from the Calvert formation at Plum Point. The species appears to be distinct, and is interesting as being the first to be definitely recognized from this continent. It is probable, however, that the small undetermined teeth figured by Leidy in the Post-Pliocene Fossils of South Carolina (Plate XXV, FIgs. 9-13), also belong to Squatina.
Description. Crown erect and comparatively
stout, convex on both faces, and with sharp cutting edges. Enamel forming a
blunt projection in front below the base of the crown, and extending as far
as the lateral extremities of the root on the outer face. Root with a flat triangular
inferior surface, and nutrient foramen situated in a slight median depression;
upper surface of root elevated into a prominent transverse fold extending from
the base of the crown to the innermost angle of the root. Total height of tooth
in the type-specimen 6 mm.; length of base 9 mm.
Occurrence. Calvert formation. Plum Point.
Collection. Maryland Geological Survey.
(these web pages were prepared by R. D. Conkwright)