ABSTRACT
The slags from Shapwick were visually inspected and classified into five categories on the basis of their morphology, density, color and vesicularity. Among the diagnostic slags are tap slag, one of the gangue products of the smelting process when iron ore is heated to produce a metallic bloom of iron, the first stage in the manufacturing of iron artefacts. The non-diagnostic residues include hearth lining, the vitrified clay lining of a hearth, usually with slag adhering to one face. Cinders are a high silica slag, generally vesicular and lighter in weight than Fuel ash slag. Coal is taken to include fully mineralised material rather than lignite or cannel coal, which was not recorded at Shapwick. At Shapwick, stratified and dateable cinders and undiagnostic fuel ash slags appear at all the Roman sites excavated, with the exception of the 'villa' site in Field 4649.
