1. Jean de Heinzelin, a legend in African geology, worked at the Institut Royal des Sciences Naturelles de Belgique, Rue Vautier 29, B-1000 Bruxelles, Belgium, until his death in November 1998.
2. Department of Anthropology;
3. Laboratory for Human Evolutionary Studies, Museum of Vertebrate Zoology, and Department of Integrative Biology;
4. Department of Geology, Miami University, Oxford, OH 45056, USA.
5. Department of Geology and Geophysics, University of California at Berkeley, Berkeley, CA 94720, USA.
6. Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, USA.
7. EES-1/MS D462, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
8. Department of Anthropology and Archaeology, Ministry of Information and Culture, Addis Ababa, Ethiopia.
9. Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA.