economic specialization. At Phalaborwa in the eastern Transvaal, for ex-
ample, people specialized in iron and copper production, and nearby in the
same Olifants River drainage system other people specialized in the man-
ufacture of salt from crusts formed by seepage from saline springs."?
Specializations such as these were the basis for complicated long-dis-
tance trade networks, which knit the region together. The Xhosa chief-
doms, for example, were linked with the Tswana chiefdoms to their north
19