Acoustic echosounding is used to classify shallow marine sediments on the basis of three quantitative parameters—the total echo spatial coherence at 3 and 10 kHz [Dunsiger et al., IEEE J. Ocean. Eng. 6, (in press)] and a subbottom windowed spatial coherence ratio (Q41 ratio) at 3 kHz. Echo coherence measures the frequency dependence of combined incoherent surface and volume scattering, the Q41 ratio measures the character of sediment internal layering. A HUNTEC DTS boomer supplies the highly reproducible broadband impulses required for optimum selection and use of these parameters. Five distinct sediment types in Placentia Bay, Newfoundland ranging from coarse gravels to clays are investigated. A classification consistency of 70%->90% is realized over visually uniform sections on analysis of clusters of 50 pings. The technique appears capable of resolving very subtle variations observed on corresponding grey scale records.