1. A long-hut group described by RCAHMW (1).
Surveyed and depicted on mapping by OS (2). The following is from the RCAHMW description with additions and amendments.

The remains are located on the W and SW facing slopes of Cefn Drum and have been cut through by tracks and paths of more recent date. The site is overgrown with heather and bracken.
Central to the site is a rectangular building measuring about 14m (E-W) by 4m within turfed-over walls spread to 2m wide and rising to 0.5m high. Some large stones are visible, especially in the SE corner. Opposing entrance gaps are visible in the long walls. The building in fact lies on a low platform, the upper (slightly embanked) E end cut back to 0.5m deep while the lower end built out to 0.5m high. Likewise embanked, the terrace lip extends 10m in an arc to the NE. To the immediate NE is a 'boot-shaped' enclosure (?pen), vaguely outlined by low banks and with overall dimensions some 9m (E-W) by 8m.
To the S of the platform, on the S side of a track, lies a second 'hut'. Only vaguely defined, it measures about 8m long (E-W) by 5m wide within low banks up to 2m wide and 0.3m high. The building is slightly platformed. About 20m to the SE is a linear hollowed feature of uncertain identity, it could be small building, measuring 7m (E-W) by 1m.
Between the three possible buildings are short lengths of banking which become a consistent feature on either side of the group of features described (2). Its total visible length is about 220m, from NNW to SSE. On the N it is a low stony bank 2m wide and up to 0.3m high, while on the S it is a lynchet up to 0.5m high.
Cultivation ridges have been noted around these features (see NPRN 91824).

(1) Glamorgan Inventory vol.III(ii), 1982, 45-6
(2) SN 60 SW 15

David Leighton, RCAHMW, 19 August 1998

2. The site has since been excavated. See J.Kissock, Studia Celtica vol.41, 2007, 1-23.