nents of southern African Iron Age sites. Their correct identification is crucial to understanding technological processes performed at these sites. This paper presents criteria for distinguishing between iron smelting slags, iron forging slags, copper smelting slags, crucible slags resulting from melting activities, vitrified clay and various biomass materials. Slag identification should entail a combination of morphology, microscopic study, chemical analysis, and assessment of the archaeological context. It is a necessarily specialist activity and superficial classification without materials analysis can be misleading. Archaeologists need to be mindful of both the archaeological opportunities and the potential technical difficulties in the interpretation of slags.
Current potters in Manaledi village in the Tswapong Hills of Botswana aver that they and their ancestors for five generations have made pottery exclusively with clay from nearby sources. We begin with an examination of Manaledi and its clay mine to uncover current dialectics between village, landscape, clay, potters, and ancestors. Archaeological sherds found around the village and clay sources document occupation by makers of Early Iron Age (ca. AD 500-750), Middle Iron Age (ca. AD 750-1050), Late Iron Age (ca. AD 1420-1800), and 18th-20th century wares related to current Manaledi pottery. The proximity of archaeological deposits, clay sources, and village made it possible to conduct simultaneously what might otherwise be considered three separate projects. As a consequence, we are able to document that Manaledi clays have been used to make pottery for some 1500 years and to consider long-standing constraints on potting this implies.
Over the last 30 years Wilmsen and Denbow have recovered and studied pottery from 28 sites in Botswana dated between ca cal AD 200 and AD 1885. Some sherds in several of these assemblages appear, on stylistic evidence, to have been made in other sub-regions of Botswana than where they were found. These inferences are confirmed in this paper by use of an independent archaeometric technique, optical petrography. We are able to demonstrate the transport of pots from the Okavango Delta to Bosutswe in the eastern hardveld, some 400–600 km distant, as early as cal AD 900–1100, and of others over equal distances to the Tsodilo Hills probably before that time. We are also able to demonstrate several shorter itineraries at contemporary and later times in the Tsodilo-Delta-Chobe region as well as in the hardveld. Furthermore, we demonstrate that clays were transported from geological deposits to sites where pots were made from them. We consider some implications of these findings for a deeper appreciation of the movement of peoples and goods at several time periods of the past and present as well as further implications for understanding the participation of the region in the Indian Ocean trade during the 8th–10th centuries.