Two building platforms, one above the other, located on the north-east facing slopes of Gelligaer Common, overlooking the Darran valley.
SO1172302631: the upper platform, densely rush-grown, measures 13.5m long (north-east by south-west) by 7.5m wide at its upper end, 5.5m at the lower end. The hood is 1m deep and its long sides are embanked, especially the north-west, up to 2m wide and 0.75m high. The terrace is built out to 0.4m high. The interior is stony below shallow turf and the lower end is slightly embanked.
SO1173402652: immediately below (hood against ramp of upper platform), a platform terrace measuring 12m long (NE-SW) with a width of 6.5m and 5.5m at upper and lower ends respectively. The hood is 1.1m deep, the terrace 0.9m high. The lower end sides of the terrace are slightly embanked.
Additional sources:
A.Fox, Archaeologia Cambrensis 94 (1939), 180 & 195.
OS record card: SO10SW19.
RCAHMW, Glamorgan Inventory vol.3 part 2 (1982), 31.
RCAHMW air photos: 945106/51, 53.

David Leighton, RCAHMW, 11 May 2016.