Figure 3. Seismic-reflection profile from line 38 of U.S. Geological Survey cruise 82-3 aboard the Woods Hole Oceanographic Institute research vessel Asterias, with interpretation (Lewis and Needell, 1987). The line crosses the eastern part of the study area and shows sand waves and a scour depression on the sea floor. The scour depression has eroded into underlying post-glacial marine sediments, which are probably mostly deltaic. This unit is underlain by a marine unconformity and glaciolacustrine sediments. In the southwestern part of the line segment, undifferentiated glacial drift (probably the flank of the Harbor Hill-Roanoke Point-Orient Point moraine segment) crops out. Location of seismic profile shown in figure 16.