1. Center for the Study of the First Americans, Departments of Anthropology and Geography, Texas A&M University, 4352 TAMU, College Station, TX 77843–4352, USA.
2. Luminescence Dating Research Laboratory, Department of Earth and Environmental Sciences, 845 West Taylor Street (m/c 186),University of Illinois, Chicago, IL 60607–7059, USA.
3. Center for the Study of the First Americans, Department of Anthropology, Texas A&M University, 4352 TAMU, College Station, TX 77843–4352, USA.
4. Department of Geology, Baylor University, One Bear Place no. 97354, Waco, TX 76798–7354, USA.
5. Department of Geology and Geophysics, Institute for Rock Magnetism, University of Minnesota, Minneapolis, MN 55455–0219, USA.
6. Department of Soil and Crop Science, 2474 TAMU, Texas A&M University, College Station, TX 77843–2474, USA.
7. Department of Anthropology, Texas State University, 232 Evans Liberal Arts, San Marcos, TX 78666, USA.