Archaeozoological material occurs mainly in open air sites of very recent date and in caves or rock shelters. The only sites in the equatorial rainforest where faunal remains have thus far been found are Matupi cave and the seventeenth to nineteenth century AD open air site of Nkile. Other cave sites such as Dimba, Ngovo and Ntadi Yomba lie presently in a heavily wooded environment (the forestsavanna mosaic). In the Grassfields of Cameroon, faunal remains were also found in a series of caves. Rapid, and by preference, deep burial of bone is necessary to make good preservation possible in open air sites. Alluvial and lacustrine deposits can, therefore, sometimes yield abundant faunal remains. This is the case of certain sites found in the Ishango region where lake deposits yielded faunal remains in a sequence studied in the 1950s (de Heinzelin 1957, Hopwood & Misonne 1959). Research was resumed in the late 1980s north of Ishango in the alluvial Semliki Beds, and also yielded sites with good faunal preservation (Brooks & Smith 1987, Peters 1990, Brooks et al. 1995). Another type of deposit where preservation conditions can be favourable are human burials such as those in the Upemba Depression region of Zaire where animal remains were found associated with human skeletons. The filling of pits is another type of deposit where preservation can be quite good when infilling is rapid. This is certainly true for the pits found at Nkang in Cameroon for instance. Finally, there are some faunal assemblages where bone is well-preserved in shell middens owing to the alkaline environment created by the shells. This is the case for Oveng in Gabon and several sites in Angola.