^,0^12 -^ Vol. 53, pp. 91-94 June 28, 1940 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON GENERAL NOTES SKULL OF FOSSIL PORPOISE, Delphinodon dividum, FROM BANKS OF POTOMAC RIVER, AT WAKEFIELD, VIRGINIA. On August 17, 1939, while in the company of Mr. John H. Dante, Mr. Robert Fuerst discovered a porpoise skull protruding from the Miocene sediments of the west bank of the Potomac River a little south of Colonial Beach, Virginia. The skull, which was badly damaged on removal, was brought to the Department of Geology and Geography at The Catholic University of America where it was restored and identified by the writer. It proved to be the remains of a fossil porpoise, Delphinodon dividum, common in the Calvert Miocene of the Chesapeake Region. The remains were exposed on the face of a ten foot cliff, about a foot above the bottom of the river. The men who removed the skull informed me that, under the best conditions, only about two inches of the posterior portion of the skull was above water. To complicate matters toward the end of the work of removal, the water had risen about a foot. In addition to this, the exposure was about fifty feet from the nearest sandy beach in a rather inaccessible location approximately a mile north of Wakefield Mansion. Under these adverse conditions it was not possible to remove the skull with the care that ordinarily could be exercised. The matrix in which the skull was embedded contained much fossil bone and consisted of a fine marine sand with very litle admixed mud. The position of the skull with respect to the strata indicated that it had come to rest at the time of burial with the rostrum inchned downwards at a con-siderable angle. From this it would appear that, after dismemberment from the rest of the body, it had been lodged in a pocket not far beyond the shore limits. The writer, in the summer of 1938, found a considerable quantity of dismembered cetacean remains in this area together with remnants of a partially ossified vertebra of the Miocene shark, Carcharodon megalodon ? which, so far as he is informed, has only been reported otherwise from Zone 12 of the Chesapeake Miocene series. The similarity of the vertebrate fauna from these two areas would make it appear that the strata in question were approximately of uppermost Calvert age. The skull, as restored, is 150 mm. wide at the orbits; 190 mm. wide at the zygomatic processes of the squamosals; and has an overall height of 100 20— Pboc. Biol. Soc. Wash., Vol. 63, 1940. (91)
BioStor
