The large tracts of estuarine alluvium which border the Severn Estuary (FIG. I) and inner Bristol Channel have never been the subject of systematic archaeological enquiry. Now largely reclaimed and known as levels, the greatest of these tracts are the Somerset Levels, on the English side, and the Wentlooge and Caldicot levels between Cardiff and R. Wye on the Welsh shore. Smaller areas of reclaimed wetland range upriver as far as Gloucester. The manner and extent to which these wetlands entered into the economy particularly in the Roman period has hitherto been assessed only in the form of speculations or inferences from circumstantial evidence, in contrast to the firmness of our understanding, based on buildings as well as artefacts, concerning military activities, settlement, and daily life on the surrounding slopes and hills beyond tidal influence.