Air photography in the drought of 1984 and in the dry summer of 1989 has produced cropmark evidence in Dyfed for a number of defended enclosures whose morphology suggests a new site type that may be commonplace throughout the region.

The county of Dyfed has good surviving earthworks of defended enclosures and small hillforts, and hitherto most discussion on settlement patterns has been confined to upstanding sites. Air surveys since 1978, especially in dry summers, have begun to produce evidence for an inadequacy in our understanding of prehistoric and native Romano-British settlement patterns with the discovery of many new defended enclosures surviving only as cropmarks. Building on the work of Professor St Joseph, numerous straight-sided defended cropmark enclosures have been revealed, although the probably mistaken assumption that some of these are of Roman date has tended to exclude them from consideration of prehistoric settlement patterns. The straight-sided cropmark noted by the author in 1984 underlying the surviving earthworks of the later prehistoric Woodbarn Rath (SN 01681703) has corroborative excavation evidence (Vyner 1986) that this cropmark at least is of earlier prehistoric date.