1. No trace could be found of a cairn depicted on an old Os map (SN83355937, Cpat Prn3437), however a recumbent white quartz monolith, 2.6m by 0.8m by 0.7m, was noted. May be a natural feature.
(Source OS495 card; SN85NW3)
J.Wiles 05.04.2002

2. RECUMBENT RECTANGULAR SECTIONED QUARTZ BLOCK 0.8M BY 0.7M AND 2.6M LONG. POSS RELATED TO `VANISHED' CAIRN PAR 3437 (RCAHM archive, 1972). (SS 8) On DRUM NANT-Y-GORLAN, 550 m above O.D. is a fallen monolith of white quartz, roughly rectangular in section 0.8 m by 0.8 m and 2.7 m in length. It appears to have fallen to the S.W. and its base on the E. remains partly buried. It tops a ridge on a S.W.-projecting moorland spur. From cartographic study it has been proposed1 that a cairn originally stood nearby. However, the earliest available source shows a quartz block here2 and the first published O.S. map depicts an enigmatic uninscribed circle.3 Lying on the S.E. edge of the same spur, some 24 m to the S.S.W. of the stone, is an oval, turf-covered mound. Its diameter is 13.8 m (N.E.-S.W.) by 9.5 m by up to 1 m high. Stone projecting from beneath it on the S.E., might indicate the existence of a kerb if the site is man-made. 1. O.S.Card SN 85 NW 3;W.E.Griffiths, Arch.in Wales, 12 (1972), p.10. 2. O.S. 2-inch MS drawing 31O W (1820-21). 3. O.S. First Edn. 1-inch (1835). RCAHMW, 1995 - Draft Inventory description. Recumbent quartz stone near the peak of Drum Nant y Gorlan. Extensive views to the Brecon Beacons in the south. Base of stone protrudes from earth. Length 2.6m, Width 0.9m, Thickness 0.83m. J.BONSALL, NT, 20/07/2002