gems, archaeology, archaeogemology, Africa, East Africa, Tanzania, Kenya

This paper describes the results of an archaeological survey on Mafia Island undertaken in July and August 1997 to search in particular for sites of early farming communities, that is of the earlier part of the Iron Age in the first millennium AD. This survey was planned in the context of recent research on that period conducted in the coastal region of Tanzania, from Dar es Salaam southwards to the Rufiji estuary (fig. 1 with inset). In previous expeditions a number of sites had been located on the mainland and also on the nearer islands of Kwale, off Kisiju, and Koma, fifteen kilometres to the south. Archaeologically these sites belong to two broad groups, some with pottery of the Early Iron Age (EIA or ‘EIW’) styles, the others with the succeeding ‘triangular incised ware’ (TIW), also known as ‘Tana tradition’ or ‘TT’. On the inshore islands of Kwale and Koma, however, only EIA pottery was noted. Some of these sites have been excavated, and radiocarbon dates obtained (Chami and Msemwa 1997a, 1997b; Chami and Mapunda 1998).