Mynydd Mallaen

Mynydd Mallaen/Crugiau Merched
Highest point
Elevation	462 m (1,516 ft)
Prominence	205 m (673 ft)
Listing	Marilyn
Geography
Location	Carmarthenshire
Parent range	Cambrian Mountains

Mynydd Mallaen is an expansive plateau to the northwest of Cilycwm in northeast Carmarthenshire, Wales. It forms part of the Cambrian Mountains massif, and is north-west of the Black Mountain (range) in the Brecon Beacons. It takes the form of an undulating plateau with steep slopes dropping away to the Towy valley to the east and those of the Gwenffrwd, Nant Melyn and Afon Cothi to the north and west. Its highest point of 1516 feet or 462m at OS grid reference SN 723455 is surmounted by two Bronze Age cairns known as Crugiau Merched (which translates from Welsh as ladies' barrows). Caeo Forest covers much of the southern flanks of the hill and smaller forests also cover its eastern slopes. Much of the native woodland consists of sessile oak groves, especially on the valley sides. The human population is very low, being restricted to hill farms engaged in sheep farming, and some holiday cottages.

The geology of Mynydd Mallaen is complex, comprising mudstones of the Claerwen Group together with sandstones of the Doethie and Glanyrafon Formations and the Caerau Mudstones Formation. Each of these Silurian rock formations is folded and faulted. Indeed it is an outcrop of conglomerate turbidite rock on the western limb of the Cothi Anticline which forms the summit of the hill. Glacial till and boulder clay from the last ice age occupies some of the hollows on the plateau, and there are many stones and boulders of white quartz scattered across the plateau, perhaps the remains of mineral veins eroded away.

...
Wikipedia