Figure 17. Detailed sidescan-sonar image of boulders and scour depressions along the northern edge of the study area. Boulders are visible as white targets with black shadows. Scour depressions are represented by light tones and are coarser grained than the surrounding finer grained sea floor, which is represented by dark tones. Stripes oriented along survey tracklines are artifacts of the data acquisition and processing. Location shown in figure 12.