A small Roman military establishment lying on the western side of the Roman road linking Pennal and Pen-llwyn is known from air photographs, trial excavation and geophysical survey . It is a roughly square enclosure with distinctive rounded corners of at least two phases. It crowns a locally prominent knoll falling steeply away on the south-west and facing onto a level saddle on the north-east. There are slight indications of features outside the enclosure to the east, hinting at a more extensive settlement centred on the fortlet.

Examination of the geophysical survey and excavation report suggests that the first phase had a ditched circuit enclosing an area 45m across. There are indications of a 5m wide rampart with a north-east facing entrance. Several of the internal buildings are likely to belong to this phase, including a possible masonry structure. Outside the main ditch are at least two slighter ditched circuits, possibly representing a single recut ditch. In the second phase a smaller enclosure was defined by a ditched circuit some 40m north-west to south-east by 35m, set within the earlier circuit and overlying it on the south-west where there are indications of an entrance. This circuit was rather differently oriented and at least one of the internal buildings is aligned on it. Limited dating evidence points to occupation in the later first-early second century AD.

Recent excavations below the site on the fringe of Borth Bog (NPRNs 400848 & 417401) explored an area of lead processing debris, including at least one furnace base. This has been confirmed as Roman by radicarbon dating and supports the hypothesis that the fortlet played a part in the exploitation of local lead and silver deposits.

Sources: Davies in the Bulletin of the Board of Celtic Studies 28 (1980), 719-29
in the Cardiganshire County History I (1994), 306-7
in Ceredigion XIII.1 (1997), 5-6
Hopewell 'Roman Fort Environs: Survey at Trawscoed & Erglodd' (2007) unpublished GAT Report No. 667
in Archaeology in Wales 46 (2006), 169-70

John Wiles, RCAHMW, 26 June 2008