Chambered Long Cairn, Nicholaston. Just below the steep southern scarp of Cefn Bryn, at about 100m above O.D., is a gently sloping tract of clay and gravel subsoil which provided the material and situation for an elongated mound. The quarrying of gravel, and the exposure of the capstone of a megalithic cist at the approximate centre of the mound, led to a thorough excavation in 1939. The site now appears as a somewhat shapeless overgrown feature, though the cist is discernible.

The mound was 37.2m long from N.E. to S.W. by a maximum of 20.4m wide, and was preserved to a height of 1.2m above the original ground surface. It consisted of successive layers of peaty soil, some with a dominant content of angular stony fragments, obtained locally and showing signs of fire, presumably from ground clearance. Larger stones formed a rough kerb defining the mound, 0.6 to 1.2 m wide and apparently surviving to its full height of 0.46m on the N.E. The chamber, built of local conglomerate, measured 0.9 by 1.2m internally, the two stones of the roof being supported at a height of 0.6m by slabs which formed the N.E. and the S.W. sides, with an additional square pillar on the E. The original access was from the N.E., across a small area of paving and a sill-stone, between two stone orthostats only 0.4m apart, but there is no suggestion of a passage from the edge of the mound. Dry walling was used to complete the sides and the whole of the S.W. end wall. The latter had been breached at an unknown date, and the contents of the tomb had been removed, though fragments of oak and hazel charcoal remained between the internal paving stones.

By Audrey Williams (Mrs. W.F. Grimes, Proc. Prehist.Soc., VI (1940), pp. 178-81), on which he above account is based.
The restriction of the entrance cannot be regarded as an indication of lateness. E.M. Clifford and G.E. Daniel in Proc. Prehist.Soc., VI (1940), pp. 162-5.

Land common to six parishes.
SS 58 N.W. (5075 8881) 30 vi 66

RCAHMW, 1976. An Inventory of the Ancient Monuments in Glamorgan, Volume 1: Pre-Norman, Part 1, The stone and bronze ages. Cardiff, Her Majesty's Stationary Office, pp.32-3 & Fig. 7