ENGELHART, S.E., Department of Earth and Environmental Science, University of Pennsylvania, 240 South 33rd Street, Hayden Hall, Philadelphia, PA 19104, HORTON, B.P., Department of Earth and Environmental Science, Univ of Pennsylvania, 240 South 33rd Street, Philadelphia, PA 19104, ROBERTS, D.H., Department of Geography, University of Durham, UK, Science Laboratories, South Road, Durham, DH1 3LE, United Kingdom, MILNE, G.A., Department of Earth Sciences, University of Durham, UK, Science Laboratories, South Road, Durham, DH1 3LE, United Kingdom, CORBETT, D.R., Department of Geology, East Carolina University, Greenville, NC 27858 and BRYANT, C., NERC Radiocarbon Lab, Scottish Enterprise Technology Park, East Kilbride, G75 OQF, United Kingdom, simoneng@sas.upenn.edu, simoneng@sas.upenn.edu