Investigations of submarine valleys

Abstract

The introduction of echo‐sounding and the use of bombs to determine positions have made it possible to discover many new submarine valleys and to develop their configuration with a speed and accuracy undreamed of hitherto. Prior to 1930 there was almost no suspicion of the presence of submarine valleys off the New England coast. The old charts showed an essentially straight 100‐fathom curve along this area, yet within the last three years 27 true canyons have been found cutting into the outer edge of the continental shelf all having depths of more than 1,000 feet below their marginal zones and attaining depths below sea‐level of over a mile. Three of these canyons discovered last summer have walls rising from 2,500 to 4,000 feet above their floors. Where these canyons have been charted in the greatest detail it becomes evident that they have the characteristics of the great river‐cut canyons of western United States (Fig. 1). They are also comparable with many of the larger submarine canyons which have been charted off the Pacific coast.