Seismic refraction measurements from the coast line to the edge of the continental shelf were made along three lines of traverse: near Cape May, N. J., New York, N. Y., and Woods Hole, Mass., respectively. An unconsolidated layer with velocity about 5800 ft/sec, a semiconsolidated layer with velocity about 11,500 ft/sec, and a layer, considered to be the basement, with velocity about 18,000 ft/sec were traced across each traverse.
On the Cape May traverse, the thickness of the sedimentary column runs from about 5000 ft. near the beach to about 16000 ft. near the edge of the shelf, in general agreement with the findings on the Cape Henry traverse in 1935. The well on Cape Hatteras, which recently reached basement at 9878 feet, confirms the seismic results. The cross-section area of the sedimentary prism off Woods Hole is much less than that off New York, which in turn is less than that off Cape May. Depth to basement increases abruptly near the beach at Cape May, and about 30 miles off shore at New York. The basement starts to slope gently upward at or just before the edge of the continental shelf on these two profiles.