[1] Energy and Geoscience Institute, University of Utah, Salt Lake City, UT 84108
[2] Purdue University, Department of Earth and Atmospheric Sciences, Civil Building 1397, West Lafayette
[3] Iowa State University, Department of Geological and Atmospheric Sciences, 253 Science Hall I, Ames
[4] University of Oslo, Museum for Geology and Paleontology, N-0562 Oslo
[5] Smithsonian Institution, National Museum of Natural History, Department of Paleobiology, MRC NHB-121, Washington, DC 20560, 10th and Constitution Ave., NW
[6] Harvard University, Department of Earth and Planetary Sciences, Cambridge, MA 02138
[7] BP America, Houston, TX 77253
[8] U.S. Geological Survey, MS 926A National Center, Reston, VA 20192