The word Kalahara corresponds with Namaqualand, Damaraland, on the west coast, Zahara Desert on the north, Makarakara salt vlei, Makalakara pits, Kasaka Bushmen of the northern parts, and many others. The boundary of this vast and interesting region comes down south to the Orange river 29 degrees South latitude, which is also the northern boundary of the Cape Colony, and extends north to the 15 degrees South latitude, the extent of my exploration. The western boundary is formed by Great Namaqua, Damara, and Ovampolands. On the east it is bounded by the Zambese to the Victoria Falls, then due south, skirts the eastern bank of the great Makarakara salt vlei, where five streams enter it from the watershed, viz. the Nata, Quabela, Shuari, Mia, and Tua; thence the boundary runs south to the Makalaka pits, a few miles to the west of Ba-Mangwato, from these pits due south to Molapololo (but that portion of Khama's country south of Mongwato down to Sechele's) to the Limpopo may be included, on to Kanya and to Maceby's Station on the Molapo down that river to Conge, Honey vlei, on to the north of Langberg range of mountains to Cowie, and down that range to the Orange river, thirty miles above Kheis. The length from north to south, as far as I have explored, is 970 miles; but, from information obtained from the Kasaka Bushmen on the spot, it may extend much further. The greatest breadth is about 500 miles from east to west, and contains within this area 280,000 square miles. The northern and eastern portion is within the Zambese basin, except that part drained by the Notuane and its tributaries, which is in the Limpopo basin, all the rest and central part is in the Orange river basin. The great watershed passes through, taking a diagonal course from the south-east corner to the north-west corner in Ovampoland. The greatest altitude above sea-level being 6100 feet, near the source of the Molapo, the lowest along the shed is 4000 feet, and in Ovampoland 3880 feet. The river system of South Central Africa has already been described in a chapter to itself, so that the configuration of the country should be more clearly understood; but it is necessary to deal with them again to a certain extent in describing the different localities and native tribes within its boundary.