Figure 6.  Map showing acoustic-backscatter intensity of the seafloor in the northern Cape Cod Bay survey area. Backscatter intensity is an acoustic measure of the hardness and roughness of the seafloor. In general, higher values (light tones) represent rock, boulders, cobbles, gravel, and coarse sand. Lower values (dark tones) generally represent fine sand and muddy sediment. Locations of sediment samples are identified as yellow circles.