Two modified cairns set upon Mynydd Mellaen: I - SN72214553, Dat Prn4096, 19m in diameter, 1.8m high, an observation channel has been cut through the cairn to facilitate use of the nearby triangulation pillar by the Os;
II - SN72327557, Dat Prn4097, 19.5m in diameter, 1.7m high. this cairn was excavated without profit in 1930, since when the excavation has become a sheepfold and a small shepherd's shelter constructed.
(source Os495card; SN74NW1)

J.Wiles, RCAHMW, 25 March 2002