Scattered prehistoric settlement of hut circles and burnt mounds. There is a possible ring cairn in the vicinity which sounds as though it may actually be a hut circle platform (the reference to the platform next to an earthfast boulder matches the ring cairn description). Various notes from Coflein:
Yr Aelgerth Hut Circle Settlement (SH5693058670)
Yr Aelgerth hut circle settlement is described in the Caernarvonshire Inventory, Vol. II, 170 (1141) as two small huts on a natural shelf at the foot of a steep slope facing E; below the shelf the ground falls to a wide marshy valley. (i) 32ft in diameter, wall 4ft thick and c1ft high, faced on both sides with large boulders. (ii) 16yds to SW similar, but 25ft in diameter with wall 3ft thick, and more ruinous. Condition poor.
Oxford Archaeology North surveyed the site, as part of the uplands initiative, in 2007, only one of the hut circles was evident. It consisted of a circular stone-built structure measuring 4.5m in diameter with double-width stone foundations up to 0.3m high. The hut circle was levelled inside and was situated sheltered against a large earthfast boulder. The site is marked on the current OS mapping.
Source: Caernarvonshire Inventory, Vol. II, 170 (1141)
RCAHMW, June 2009
Yr Aelgerth Hut Circle I (SH5704658689)
Possible hut circle foundations. It measures 7m in diameter and is constructed of large boulders and has a large holly tree growing through it. P.J. Schofield, OANorth, 8th June 2007
Yr Aelgerth Hut Circle II (SH5707858899)
A sub-oval domestic structure, possibly a hut circle. The site is platformed into the slope and levelled in the centre. It consists of double thickness rough stone walls, mostly collapsed with an internal kerb of large boulders,. It measures 7m long by 5.5m wide and the foundations stand to a maximum of 0.3-0.4m high. P.J. Schofield, OANorth, 12th June 2007
Ty'r-mawn Hut Circle (SH5713059120)
Double thickness foundation of boulder walls, measuring 10m in diameter and terraced into the hillside. The northern half has been reduced to ground level, but the foundations are still visible. The southern part has been rebuilt as a sheep fold up to 1.2m high. The site is marked on the current OS mapping.
It is described in the Caernarvonshire Inventory, Vol. II, 171, (1147). Mound of burnt stone near Hafod-uchaf, at 800ft above OD. The horseshoe-shaped mound faces NW towards a small stream, now dry. It measures 30ft by 35ft with traces of a stone revetment on the NE and SE. Condition: good. OAN Site visit 2007. A burnt mound marked on the current OS mapping. It consists of an obvious kidney-shaped mound sat adjacent to a watercourse. It measures 13m long by 8m wide and is up to 1m high. The site is marked on the current OS mapping.
Hafod-uchaf Burnt Mound II (SH5736658888)
A possible burnt mound located on the sloping ground above the edge of improved pasture fields near Hafod-uchaf. It is sub-circular in shape and measures approximately 7m long by 6m wide and up to 0.5m high. It is located immediately adjacent to a stream and is some 45m south of an already identified burnt mound (NPRN 505509). P.J. Schofield, OANorth, 8th June 2007