Mynydd Llangynidr

Mynydd Llangynidr is a hill in the Brecon Beacons National Park largely in the county of Powys, south Wales. Its southern slopes extend into the northernmost parts of the county borough of Caerphilly. It is named from the village of Llangynidr which sits in the valley of the River Usk to the north of it. It is essentially an undulating plateau rising in the west to a height of 557m at Garn Fawr at OS grid ref SO 123151. A secondary high point is achieved at a point marked by a trig point at SO 147159. To the north the hill overlooks the valleys of Dyffryn Crawnon and Cwm Claisfer, themselves tributary valleys of the Usk. The shallow upper valley of the Ebbw River reaches into the plateau in the south whilst the upper reaches of the Sirhowy Valley and its tributary the Nant Trefil define its western margins. Passing east across the B4560, the hill merges with Mynydd Llangatwg which has a similar character. ^[1]

Geology

Mynydd Llangynidr is formed from a layer cake of Palaeozoic era sandstones and limestones which dip gently southwards into the South Wales Coalfield basin. Broken cliffs of Carboniferous Limestone occur along the northern edges and this rock underlies the entire hill. The plateau is formed from coarse sandstones ('gritstones') also dating from the Carboniferous period and which have foundered in many places as the underlying limestone has dissolved over millennia. The larger part of the hill has a pock-marked appearance due to the hundreds of shakeholes in its surface arising from the presence of the limestone beneath the sandstone cover. The most celebrated cave on Mynydd Llangynidr is Ogof Fawr or Chartist's Cave (so named as it was reputed to be a hiding place for the Chartists of South Wales), situated 500m to the east of the top of Garn Fawr. ^[2]

Quarrying

A couple of major limestone quarries intrude upon the hill. There is an active quarry at Trefil whilst that at Blaen Onneu in the northeast has not been worked since the 1980's. There are also a few small quarries for limestone which predate the larger workings.

Archaeology

There are numerous ancient cairns on this tract of moorland, the most notable of which are Garn Fawr ('big cairn') and Carn Caws ('cheese cairn'). Other prehistoric cairns and a stone row together with evidence of house platforms occur towards its northern edge.

Access

The hill is mapped as open country and therefore freely available for walkers to roam at will. There are few defined paths though two public footpaths cross from north to south from Llangynidr towards Tredegar. The B4560 road from Garnllydan to Llangynidr cuts across the high moorland to the east of the hill and offers the easiest access to both Mynydd Llangynidr and to Mynydd Llangatwg to its east. To the west a minor road heads north from the A465 Heads of the Valleys Road through the small village of Trefil and continues north as a bridleway, also offering easy access to the hill.

External links

images of Mynydd Llangynidr from Geograph website

References

1. ^ Ordnance Survey Explorer map OL13 'Brecon Beacons National Park: eastern area'
2. ^ British Geological Survey 1:50,000 map sheet 232 'Abergavenny' & accompanying memoir

Coordinates: 51°49′N 3°19′W / 51.817°N 3.317°W / 51.817; -3.317