Amino acid and other studies have been made on the 30-km Pleistocene sections of the Intracoastal Waterway between Myrtle Beach and Little River, South Carolina. Our ratios differentiate the long-established Waccamaw (oldest), Canepatch, and Socastee formations. The ratios from the four laboratories that have worked in this area agree very well, and apparent conflicts with U-series dates may merely reflect an abundance of reworked corals. Our amino acid correlations with U-series coral dates in South Carolina, Bermuda, and the Mediterranean all argue that the classical Canepatch and its Horry Clay date from isotope stage 5e and not, as has been implied, from stage 7, 9, 11, or 13. Excavations and erosion have increased position-fixing problems along the Waterway, and “Canepatch” amino acid ratios and U-series dates (460,000 ± 100,000 yr B.P.) at “ICW5” may be from an older unit. The Canepatch shows the double marine transgression visible in many stage 5e deposits. Pollen shows that the second transgression occurred late in the interglaciation, and stratigraphic studies show that it reached 14 m. It therefore fits very well Antarctic ice-surge models of stage 5 sea level and climate. The Socastee adds to the evidence for one or more sea levels above 0 m late in stage 5.

Wilson's theory of ice ages implies that the present interglacial will end with, or at least be interrupted by, an Antarctic ice sheet “surge”. Such surges in the past would have caused distinctive rises of sea level: by 10–30 m, in 100 yr or much less, and precisely at the break of climate at the end of each interglacial. Lithostratigraphic, pollen-analytic and radiometric evidence hinting at such a rise (to 17 m?) late in the last interglacial (at about 95,000 BP?) is found in the Spencer's Point formation in Bermuda, the Ladson and Canepatch formations in S. Carolina, the Norfolk formation in Virginia, and above the Walker interglacial swamp in Washington, DC. The strongest evidence that could be found against this rise would be pollen diagrams up toward 17 m which showed continuously freshwater conditions late in the interglacial. Features that might be explained by a surge occur in the Camp Century ice core, in Atlantic, Caribbean and Gulf of Mexico marine cores, and in the Orgnac stalagmite.