1. Department of Curriculum, Instruction, and Special Education, Mississippi State University, P.O. Box 5448, Starksville, Mississippi 39762, USA
2. Department of Geosciences, Mississippi State University, P.O. Box 5448, Starksville, Mississippi 39762, USA
3. Department of Curriculum and Instruction, University of Arkansas, 216 Peabody Hall, Fayetteville, Arkansas 72701