J Archaeol Sci 29 (4)

Reports the thirty-three-year section of the Wareham Experimental Earthwork, which provided a unique opportunity to investigate the retention and leaching of phosphate released as bone rapidly decomposes in a lowland heath environment. The soils are extremely acidic, sandy, Fe-deficient podzols, with naturally very low, though variable, phosphate concentrations. Phosphate released from bone buried (i) on the old ground surface beneath the bank (`turf environment') and (ii) within the sands of the bank (`sand environment') was found to have leached very rapidly. Indeed, only one of 200 samples from the two burial environments shows signs of phosphate enrichment. The higher rate of bone decomposition recorded in the sand than in the turf environment in previous excavations of the Earthwork is attributed to more active leaching in the better-drained sands. The discovery in the present excavation of one relatively well-preserved piece of bone in the sand environment suggests that certain micro-environments within the sand matrix are more favourable for bone preservation, presumably because of reduced rates of water seepage and/or less acidic conditions. The implications of these findings for soil phosphate studies and bone preservation in acid heathland soils are discussed, and comparisons made with results from the thirty-two-year section of the chalk downland Earthwork at Overton Down.

Isolated and usually undated human crania from riverine deposits in the British Isles is seen to present something of an archaeological mystery. The large numbers sometimes involved -- several hundred from the River Thames alone -- together with the recovery of unassociated metal artefacts have been taken to imply `ritual' activity. A taphonomic investigation of human crania and ungulate remains obtained from dock excavations during the 1880s is presented. Although apparently recovered in close spatial proximity, a series of AMS determinations on crania of humans, aurochsen (Bos primigenius) and red deer (Cervus elaphus) has established at least a Neolithic to Saxon age range for the sample. Such a chronological span for a diverse assemblage when considered against modern forensic studies of the taphonomy of bodies in water strongly implies that the human crania need represent no more than an accumulation of elements that normally separate quite naturally from the rest of the body. While the reasons for initial entry to the water may well have included `ritual' activity in one or more case there is thought to be no reason to infer such behaviour for the human sample as a whole in the absence of direct evidence.