Many geologists have stated that marine sediments vary from coarse to fine directly as the distance from shore and the depth of water increase. Such gradation seems so reasonable in view of our knowledge of waves and currents that what is practically a geologic axiom has come into existence. Most standard textbooks assume that this principle applies to the sediments on the present continental shelves. A well-known text states that “sand generally does not extend beyond a depth of 250 to 300 feet and the outer portion of the continental shelf is therefore covered by muds alone.” Others emphasize the same principle but are less definite in their statements. The belief that such gradation of sediments occurs on the continental shelves evidently developed without regard for the abundant record of bottom samples obtained during the charting of the shelf seas for navigational purposes. The character of the bottom is . . .

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