Recentin situand laboratory determinations of density and velocity of sound in fine‐grained, high‐porosity sediments of the sea floor off San Diego, California, reveal several stations at which the velocity of sound in the sediment was 2% to 3% less than the velocity of sound in the water just above the bottom. Comparison of the compressibility of the sediment computed in two ways and of the ratio: velocity in sediment/velocity in water computed and actually measured indicates that these high porosity sediments are approximately described acoustically by the velocity formula which applies to a suspension. The theoretical explanation for this phenomena was apparently made by R. J. Urick, [J. Appl. Phys.18, 983 (1947); J. Acoust. Soc. Am.20, 283 (1948)] and R. J. Urick and W. S. Ament [J. Acoust. Soc. Am.21, 115 (1949)].