This is a project to continue the Berkeley Geochronology Center's (BGC) radioactive Argon dating of hominid and hominoid fossil localities in East Africa. This is being done as a collaborative effort together with other scientists conducting studies in paleoanthropology, archaeology, and geology at the same fossil- bearing localities. The BGC's previous dates have provided important age results for Olduvai Gorge, among other important East African sites. This dating technique provides the basis for understanding the stratigraphy and paleoenvironment of the hominid fossil record.