A 1940 survey project of the U. S. Coast and Geodetic Survey Ship Oceanographer commanded by Comdr. Fred. L. Peacock reveals a wealth of new information in the Gulf of Maine. This vessel was equipped with a visual fathometer and a graphic recorder fathometer operating simultaneously. Hydrography on a scale of 1:120,000 consists of 15,300 miles of sounding lines concentrated in an area of approximately 8900 square statute miles. Recorded soundings exceed 155,000. Physiographers now have valuable information to assist in solving the past history of this region including the role of continental glaciation.
The submarine relief is complex, with features rising from 50 to 500 feet above the floor of the Gulf. Cashe Ledge, the highest feature, rises 485 feet from the floor to within 25 feet of sea level. The basins are relatively broad and shallow, lying at depths of about 500 to 1000 feet. Base level of about two-thirds of the area surveyed is about 760 feet.
The basins have dual-bottoms, tentatively termed as “sediment” overlying the substrata. This sediment, ranging in thickness from a thin film to approximately 90 feet, is generally restricted to depths greater than 500feet and is more prevalent in the deeper basins. The manner of its distribution is variable, but generally it smooths out irregularities. Anomalously, the sediment is sometimes absent in the deepest portion of a depression.
Emphasis is given to illustrations of sounding data. These consist of 5-fathom interval contour maps of the surveyed area and 231 representative fathogram profiles covering features of interest. The latter illustrate 1500 statute miles of graphic recorder sounding lines.