The use of geophysical methods for the solution of geological problems has been rapidly gaining favor during the past few years, largely due to the great success attained by those engaged in petroleum exploration. It is particularly fortunate that geophysics should have early commended itself to commercial concerns, for, otherwise, lack of funds might have hampered its progress. Geologists who are engaged in non-commercial investigations have appreciated the importance of this new tool but have been prevented from using it extensively because of the relatively great expense involved as well as the difficulty of securing properly trained men to collect the geophysical data. This paper is concerned with the geological interpretation of results obtained in a geophysical investigation of somewhat novel character, under the leadership of Maurice Ewing. It accompanies a paper by Ewing, Crary, and Rutherford, which should be read in conjunction with this article, in order properly . . .