The Wentlooge Level in SE Wales represents an extensive area of some 35 km2 of alluvium reclaimed from estuarine saltmarsh from the Romano-British period onwards (FIGS 1-2). As was noted by Allen, the landscape is characterised at its southern and northern extremities by a pattern of small irregular fields, often fossilizing the meanderings of natural drainage channels (FIG. 2). This arrangement is typical of many of the reclaimed alluvial wetlands that fringe the Severn Estuary. The remainder of the Wentlooge Level is distinguished by a very different landscape, comprising regularly planned blocks of long, narrow, and generally straight-sided fields, quite unique among the wetlands of the Severn Estuary. At Rumney Great Wharf, north east of Cardiff, part of the latter field-system can be seen cut into a clay-peat shelf in the intertidal zone (see below), thus indicating a major episode of coastal retreat and the repositioning of the sea-wall across it; similar evidence from the intertidal zone can be recognised as far to the north-east as Peterstone Gout. An extensive spread of Romano-British pottery and primitive iron-making slag was associated locally with this field-system in the intertidal zone at Rumney Great Wharf, while survey of the adjacent mud cliff revealed at least one ditch, sealed by a buried palaeosol, which yielded stratified Roman material. Further erosion of the mud cliffrevealed more ditches with Romano-British material, as well as other indications of settlement, and prompted a programme of survey and excavation grant-aided by Cadw and the National Museum of Wales in the spring of 1992.