Over the last million years, the Sahara has oscillated between the hyperarid conditions with which we are currently familiar and a decidedly more humid climate. These climatic fluctuations had a substantial impact on the capacity of the region to support animal populations. During the rainy, or ""pluvial"" periods, hominids settled stretches of the desert. In central Egypt, fossil spring deposits preserve a record of pluvial phases and contemporaneous occupation of the desert as they occasionally encase lithic artifacts. The geochronology, stable isotope geochemistry, and stratigraphy of these deposits can be used to reconstrtuct a coupled cultural and climatic chronology for the region.