From the Usk to the Taf
In addition to the village of Llanfrynach, the Community comprises the villages of Llechfaen, Groesffordd and Llanhamlach and extends southwestwards into upper Cwm Taf.
The lie of the land
Llanfrynach community stretches from 120m above sea level in the Usk valley near Llanhamlach to a height of 886m at Pen y Fan, the highest summit in southern Britain. Other important summits include those of:
- Cribyn 795m (SO 023213)
- Fan y Big 719m (SO 036206)
- un-named summit at Bwlch y Ddwyallt 754m (SO 055203)
It is drained by the Nant Sere, Nant Cynwyn and Nant Menasgin each of which flow into the River Usk which runs through the northern part of the area.
Solid rock
The northern part of the area is underlain by the red to purple mudstones and siltstones of the St Maughan’s Formation. The higher ground to the south is formed from the sandstones of the Senni Formation and the overlying Brownstones Formation.
Overlying these in turn is the Plateau Beds Formation, whose hard sandstones cap Pen y Fan and form the tops of Graig Fan Ddu and Gwaun Cerrig Llwydion either side of the Neuadd reservoirs.
The rocks all have a general southerly or south-easterly dip. A number of geological faults run NW-SE through the area influencing the course of the River Taff for example.
Legacies of the Ice Ages
Some of the finest glacial cirques in South Wales have been excavated by ice on the northern slopes of the Brecon Beacons. They include those at the heads of Cwm Sere, Cwm Cynwyn, Cwm Oergwm and Cwm Cwareli. Moraines can be distinguished below the rocky headwalls of each of these.
Much of the ground to the north of the hills is mantled by glacial till whilst areas of hummocky sand and gravel occur around the village of Llanfrynach.
There are major landslips on the northern slopes of Cefn Cyff and again above Blaen Taf Fechan.
Archaeology
There is a scatter of cairns and standing stones in the uplands.
Maps
Geology
Sheets 213 ‘Brecon’ & 231 ‘Merthyr Tydfil’ of the British Geological Survey’s 1:50,000 maps series of England and Wales give full coverage between them of both the bedrock geology and superficial deposits of the part of the Community area which falls within the Geopark.
Coverage of the entire Community area is completed by sheet 214 ‘Talgarth’.BGS publishes memoirs and sheet explanations to compliment these maps.
General
The following Ordnance Survey maps cover the Community:
- Landranger sheet 160 ‘Brecon Beacons’ (1:50,000 scale)
- Explorer sheet OL12 ‘Brecon Beacons National Park/Western area’ (1:25,000 scale)
Public transport
Bus services operate along the road.
See Traveline Cymru for bus and train services including stops, timetables and route-planning information.