There are at least 11 platforms, with a possible twelfth, spread out along north-east facing slopes of Gelligaer Common above the Darran Valley, roughly following the 400m contour (see NPRNs 15319-23 & 305961-2). They are rectangular, mostly with long axes at right angles to the slope, cut into rising ground with material dumped outwards to form a level terrace above the slope. Some have superficial traces of buildings upon them. A twelfth platform, at the far south-east end of the group, is possibly no more than a quarry scrape.
Traces of cultivation in the form of plough ridges extend over a wide area on this side of the common, associated with a linear bank and a small mound, features which seemingly respect the platforms. However, it is likely that the cultivation is of much later date (see NPRN 421575).

David Leighton, RCAHMW, 20 April 2016