Language: English with trilingual preface in English, French, and Dutch
The Upper Semliki valley, part of the Western African Rift, is of special interest to paleontologists and to prehistorians. Existing reports are scattered, incomplete and of unequal reliability. The authors assembled and cross-checked all available geological data, from the first explorations in 1938 to the last excavations in 1990, in order to produce a twofold synthesis; this is, on the one hand a geological map on which all observations, measurements, excavations and fossil assemblages are pointed, on the other hand a coherent overview of the stratigraphy and of the landscape development in function of tectonics and volcanics. Formal and informal formations are designated, together with the relative importance of the intervening diastemes and fossil soils. The authors discuss pending arguments on the datation and significance of major archaeological sites such Ishango, Katanda and Senga-5A.