This book is on the sedimentology of a prominent geomorphological expression on the terrains covering the Chad Formation in Bornu Sub-basin,Chad Basin Nigeria. Using practical sedimentological procedures encompassing section logging and descriptions, lithofacies analyses,Xray diffractometry,Heavy mineral and micropalaeontological methods,a fluvio-lacustrine depositional environment is ascribed to the sediments.Further studies revealed that these sediments are a separate stratigraphic entity from the overlying Chad Formation.