1. 1 Department of Geography and Geology, University of Nebraska Omaha, 6001 Dodge St., Omaha, NE 68182-0199
2. 2 Department of Earth and Atmospheric Sciences, Saint Louis University, 3642 Lindell Blvd., St. Louis, MO 63108; current address – SHANNON & WILSON, 2043 Westport Center Dr., St. Louis, MO 63146