Dredge‐samples from the submarine canyons between the Hudson Gorge and Chesapeake Bay

Abstract

In August, 1935, the research vessel Atlantis of the Woods Hole Oceanographic Institution made a dredging trip to the outer part of the Hudson Gorge, to two valleys cutting the continental margin off the Delaware coast between 30° 30′ and 38° 06′ north latitude, and to one off Maryland lying between 37° 30′ and 37° 20′ north latitude. With the exception of the outer gorge of the Hudson, these canyons are in every way similar to those described by Shepard from Georges Bank, and their general configuration is too familiar to everyone to warrant further description here (F. P. Shepard, Canyons off the New England coast, Airier. J. Sci., v. 27, pp. 24–36, 1934). In many places the slope of the walls is apparently above the angle of repose of unconsolidated material, and presumably cliffs of truncated strata form part of the canyon walls. It is not the purpose of this preliminary report to enter into a discussion of the origin of these features. We are only concerned here with the nature of the material found within the canyons themselves. Whatever their origin may have been, it is obvious that factors were once in operation the dating of which would be of importance to geologists. Last summer's reconnaissance was a continuation of the problem begun the preceding year on Georges Bank, namely, of attempting to fix the maximum age of these valleys by means of fossiliferous samples dredged from their walls and, secondly, of gaining some knowledge of the type of material of which the continental margin is composed.