Figure 10: GPR profile (CAMP) from the mid-section of the Clatsop Subcell showing internal stratigraphy of large foredune beach-ridges. From the modern foredune side (left of figure) the groundwater surface reflector enters the profile at a distance of 300 m (near the 1870’s shoreline position). A prominent truncated paleosol reflector enters the profile at a distance of 430 m. Subhorizontal foredune ridge reflectors are shown above the groundwater surface reflector between 500-700 m distance (Big Dune complex) and at 940 m distance, and in the Mid-Dune Ridge at 1300-1430 m distance.