Carn Pen-rhiw-ddu

Rising on the western fringes of the Black Mountain, this moorland summit marks a rugged transition between the limestone pavements of Carreg yr Ogof and the high peaks of the Fans. Characterised by gritstone boulders and peat, the top offers an uncrowded vantage point over the remote Sawdde valley and the wilder Carmarthenshire hills.

• •The name is derived from the Welsh 'Carn' (cairn), 'Pen' (head or top), and 'Rhiw-ddu' (black slope), specifically referring to its position above the dark, heather-clad inclines that drop away into the valley of the Sawdde Fechan.
• •The summit is often visited as part of a high-level circuit from the mountain road at Herbert's Quarry, linking the gritstone plateaus with the nearby dramatic limestone outcrops of Carreg yr Ogof.
• •From the summit cairn, walkers earn an excellent perspective of the western escarpment of the Carmarthen Fans, with the sharp profiles of Picws Du and Fan Foel clearly visible across the deep glacial trough to the east.
• •Given the density of peat hags and hidden limestone shakeholes in this corner of the range, the 'black' in the hill's name is often a very accurate description of a walker's gaiters after a day exploring the plateau.