Stratigraphy, archaeology, and age of the Ndutu and Naisiusiu Beds, Olduvai Gorge, Tanzania

The upper part of the stratigraphic section of Olduvai Gorge is subdivided into the Ndutu Beds and the Naisiusiu Beds ; Beds Va and V are abandoned as stratigraphic terms. The Naisiusiu Beds are uppermost Pleistocene and give C14 dates of 10,400 to 17,550 B.P.; the Ndutu Beds are largely upper Pleistocene, but may include middle Pleistocene deposits. Faulting in the Olduvai region continued through the deposition of the Ndutu Beds, but apparently ceased before the Naisiusiu Beds were deposited. The Naisiusiu Beds contain a microlithic assemblage of late Upper Palaeolithic facies; the Ndutu Beds contain a Middle Stone Age archaeological assemblage.