On top of the steep W bank of a tributary stream of the upper Tawe at c.460m above OD a group of boulders and large stones appears to form the outline of a rectangular building. It is best defined on the S and E sides by large blocks and slabs (with some smaller stones) up to 1.2m across and 0.4m high. The W side is formed by a low inner facing scarp, and a low outer facing scarp obscured by rushes forms the N end which may also incorporate outcrop.
The structure measures overall 7.9m (NW-SE) by 5m.

visited DKL 27.5.93