The Pliocene to Recent sand sea in the central part of the 2000 km long Namib Desert is underlain widely by sediments comprising the Tsondab Sandstone Formation (TSF) of Early to Middle Tertiary age. This formation is the earliest record of terrestrial sedimentation in the central Namib Desert and formerly was thought to consist of only eolian dune and sand sheet deposits of a desert origin. However, recent field investigations indicate that the TSF also includes deposits of ephemeral watercourses and pans (playas). These fluvial and playa sediments are associated intimately with the eolian dune and sand sheet deposits, as is likewise the case in the present, extreme-arid Namib Desert. Sedimentary structures and trace fossils in the TSF eolianites resemble those found in the modern sand sea. Furthermore, these eolianites were deposited under a dominant southerly and a subordinate easterly quadrant wind regime which is similar to the present-day circulation pattern in the Namib. Since the cold Benguela Current was established only in the Late Tertiary, the TSF represents a major, ancestral arid phase in the Namib tract that was controlled by an early anticyclonic wind regime and a geographic location on the rainshadow side of southern Africa.