The area described in the following pages is situated between 15° and 16° east longitude, and 21° 30' and 22° south latitude ; Karibib (B. 4) in the south-eastern part of the area and Usakos, just below the 22° latitude line, form the major social centres. Both towns are on the main railway line between Windhoek and Swakopmund, while Usakos is also the junction station for the narrow-gauge railway line to Grootfontein and Tsumeb. The area was geologically surveyed in 1928 by Drs. T. W. Gevers and H. F. Frommurze. During 1937 Mr. P. J. Rossouw was commissioned to revise the area and to pay special attention to and re-map portions of economic significance.