Correlation of the African Silurian rocks

The Silurian marine rocks of North Africa are distributed in a northeast-southwest-trending strip from Sierra Leone on the southwest to the Kufra Basin on the northeast grading into nonmarine beds to the southeast. The Silurian shore-line progrades to the northwest in a movement from the southern to the central Sahara at the beginning of the Silurian to Algeria by the end of the Silurian. Silurian lithofacies and paleogeography of North Africa are easily related to those of southern Europe and the Near East. Both of these regions can be considered a s the natural continuations of the North African Silurian. The marine platform mudstones and siltstones of the North African Silurian grade vertically upward into nonmarine-type sandstones in most places. The age of these sandstones is highly diachronous, being a function of the prograding shoreline present during Silurian time. The North African Silurian faunas are chiefly of a pelagic, planktonic type; shelly benthic faunas of the type abundant in most Northern Hemisphere regions are absent with their absence being ascribed to a cold water regime affecting North Africa. Marine Silurian of shallow water type, faunally similar to that of southern South America, is known from the Capetown area of South Africa. The South African Silurian is easily related to that of Argentina, Peru, and Bolivia. The South African fauna belongs to the endemic Malvinokaffric Province of the Silurian, as does part of that from North Africa. At the boundary between the Silurian and the Ordovician in much of the central North African region there is evidence of continental type glaciation.