Cefn Cil Sanws is a hill in the Brecon Beacons National Park within Merthyr Tydfil County Borough in south Wales. The summit at 460m above sea level is crowned by a trig point. The steep cliffs of Darren Fawr and Darren Fach defend its western side which drops down into Cwm Taf. A major limestone quarry is worked on the southeastern side of the hill. An unexpected feature at this altitude is Merthyr Tydfil Golf Course which extends high onto the eastern and southern slopes of the hill. [1]
The hill is composed of a layer cake of rocks of Carboniferous age all tilted moderately to the south. The summit is formed from Carboniferous Limestone whilst outcrops of Twrch Sandstone (formerly known as the 'Basal Grit' of the Millstone Grit Series) can be seen to the north and on its steep western flanks. There are sections of limestone pavement on the tilted plateau surface and small crags and pavements of gritstone to their south. The latter show evidence of glacial striations suggesting that the hill was over-ridden by ice moving southwards from the central Beacons during the ice ages. [2]
Much of the hill is owned and managed by the Brecknock Wildlife Trust as a nature reserve. The steep cliffs of Darren Fach on the western side are the home to Britain's rarest tree - Ley's Whitebeam (Sorbus leyana) - the larger part of the country's population of these trees being found on this one cliff. Also of interest is the rare rigid buckler fern which clings to the scree slopes on this western flank. [3]
Most of the hill is open country. A public footpath and a bridleway at its southern end provide access from the A470 road and from Cefn-coed-y-cymmer.
The Brecon Beacons, or Bannau Brycheiniog ( ), is a mountainous region and national park in Wales. The name 'Brecon Beacons' was originally applied only to the mountain range south of Brecon, Powys, which is now also known as the Central Beacons. The range includes South Wales' highest mountain, Pen y Fan, its twin summit Corn Du, and Craig Gwaun Taf, which are the three highest peaks in the range.
The Black Mountain is a mountain range in South, Mid and West Wales, straddling the administrative boundary between Carmarthenshire and Powys and forming the westernmost range of the Brecon Beacons National Park. Its highest point is Fan Brycheiniog at 802 metres or 2,631 ft. The Black Mountain also forms a part of the Fforest Fawr Geopark.
Sorbus leyana. Ley's whitebeam is a species of small tree which is endemic to two sites in southern Wales. It is thought to have arisen by hybridisation of two species of Sorbus, one of which was the rowan. Its closest relatives are some of the other hybrid derived Sorbus species found in Britain.
Cefn yr Ystrad is a mountain in the Brecon Beacons National Park in Wales. It is an outlier of the Central Beacons group.
Fan Fawr is a mountain in the Fforest Fawr section of the Brecon Beacons National Park, in Powys, Wales and over 734 m (2,408 ft) high.
Pen Cerrig-calch is a subsidiary summit of Waun Fach in the Black Mountains in the Brecon Beacons National Park in southern Powys, Wales. Its summit, at a height of 701 m (2,300 ft), is marked by a trig point. The peak sits high above the River Usk valley as it narrows above the small town of Crickhowell. The views from here are wide-ranging and extend as far as the Beacons themselves to the west. A ridge runs off to the northwest and the shoulder of Pen Gloch-y-pibwr then turns north to the secondary top of Pen Allt-mawr whose peak at 719m is also crowned by a trig point.
The Nedd Fechan is a river almost wholly within the county of Powys, Wales, currently administered as part of the unitary authority of Powys. It rises on the eastern slopes of Fan Gyhirych in the Fforest Fawr section of the Brecon Beacons National Park and flows south for 7 miles (12 km) to join with the Afon Mellte at Pontneddfechan, their combined waters continuing as the River Neath to the sea near Swansea. The only significant tributary of the Nedd Fechan is the Afon Pyrddin which joins it at Pwll Du ar Byrddin. Downstream of this confluence it forms the boundary between Powys to its east and Neath Port Talbot to its west.
Fforest Fawr is an extensive upland area in the county of Powys, Wales. Formerly known as the Great Forest of Brecknock in English, it was a royal hunting area for several centuries but is now used primarily for sheep grazing, forestry, water catchment and recreation. It lies within the Brecon Beacons National Park.
The Nant Gwys is a river flowing off the Black Mountain in Powys, Wales. Its tributaries Gwys Fawr and the Gwys Fach flow south from Banwen Gwyn and Bwlch y Ddeuwynt respectively and join forces to form the Nant Gwys proper which then flows for about 5 km / 3 mi to its confluence with the Afon Twrch at Cwm-twrch-Uchaf.
Fforest Fawr Geopark is a Geopark in the Brecon Beacons National Park, south Wales. It is the first designated Geopark in Wales having gained membership of both the European Geoparks Network and the UNESCO-assisted Global Network of National Geoparks in October 2005. The Geopark aims to promote and support sustainable tourism and other opportunities to improve the economy of the area whilst safeguarding the natural environment. Its aims largely coincide with the statutory duties and purpose of the National Park within which it sits.
Moel Penderyn is a hill on the edge of Penderyn village, in the Brecon Beacons National Park in the county borough of Rhondda Cynon Taff, south Wales. It also appeared on older maps as 'Y Foel Penderyn'. Its summit at 371m is marked by a trig point.
Cribarth is a hill in the Brecon Beacons National Park, Powys, Wales, in the traditional county of Brecknockshire. The summit lies on the broken ridge at an elevation of 428 m (1,404 ft) at OS grid reference SN 831143. To its west is a 426-metre-high (1,398 ft) rounded top at SN 829144 which lies just to the northwest of a mile-long ridge that forms the main bulk of the hill. The ridge attains a height of 423 m (1,388 ft) at its southwest end and this spot is marked by a trig point. Both of these latter high points are adorned by Bronze Age burial cairns.
Foel Fraith is a hill in the Black Mountain in the county of Carmarthenshire, southwest Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark. Its plateau-like summit attains a height of 602 metres (1,975 ft) above sea level. To the north the subsidiary summit of Cefn y Cylchau reaches 556 feet (169 m), and to the southeast is the subsidiary summit of Carn Fadog or Cefn Carn Fadog, which reaches a height of 512 metres (1,680 ft).
Cadair Fawr is a hill in the northern corner of the county borough of Rhondda Cynon Taf, Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark. The 485m high summit at OS grid ref SN 978123 is marked by a trig point. Cadair Fawr is the highest point of a broad ridge known as Cefn Cadlan which forms the northern edge of Cwm Cadlan, a valley which itself runs east-northeastwards from the village of Penderyn. The name Cadair Fawr signifies the 'big chair' whilst Cefn Cadlan signifies the 'ridge of the battlefield'.
Mynydd-y-glog is a hill just east of the village of Penderyn in the northern corner of the county borough of Rhondda Cynon Taff in south Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark. Its summit plateau rises to a height of 389m / 1277 ft at OS grid ref SN 982088, a spot marked by a trig point. To its north lies the partly dry valley of Pant Sychbant which forms the eastern extension of Cwm Cadlan. Its southern slopes are drained by various streams which feed into the Afon Cynon.
Penmoelallt or Onllwyn is a hill in the northern part of the county borough of Rhondda Cynon Taff in south Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark. To its east lies the deep valley of Cwm Taf and to its north a rather shallower valley in which the Nant Cadlan originates. To the west is the hill known as Mynydd-y-glog and to the south are slopes draining into the River Taff and the Afon Cynon. The hill culminates in a broken plateau with several knolls rising above the 420m contour. Its afforested nature makes it difficult to determine the precise location of its highest point but this probably lies somewhere around OS grid ref SO 003096. Older maps indicate a spot height of 1376 ft above sea level at SO 000090.
Carreg Cadno is a hill five miles northeast of Abercraf in the county of Powys, south Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark. Its summit at OS grid ref SN 874161 reaches a height of 538m / 1763 ft above sea level. The hill is within the Ogof Ffynnon Ddu National Nature Reserve which is owned and managed by the Countryside Council for Wales.
Mynydd Carn-y-cefn is the name given to the broad ridge of high ground between the Ebbw Vale and the valley of the Ebbw Fach in the Valleys region of South Wales. It lies within the unitary area of Blaenau Gwent, formerly Monmouthshire.
Cefn-coed-y-cymmer is a small community on the northwestern edge of Merthyr Tydfil County Borough in Wales. It is situated in the neck of land between the rivers Taf Fawr and Taf Fechan at their confluence. The village lies within the community of Vaynor. Immediately to the north of the village is the hill of Cefn Cil Sanws on the southern slopes of which is Merthyr Tydfil Golf Club. The village is bounded both to the north and the west by the Brecon Beacons National Park.
This article describes the geology of the Brecon Beacons National Park in mid/south Wales. The area gained national park status in 1957 with the designated area of 1,344 km2 (519 sq mi) including mountain massifs to both the east and west of the Brecon Beacons proper. The geology of the national park consists of a thick succession of sedimentary rocks laid down from the late Ordovician through the Silurian and Devonian to the late Carboniferous period. The rock sequence most closely associated with the park is the Old Red Sandstone from which most of its mountains are formed. The older parts of the succession, in the northwest, were folded and faulted during the Caledonian orogeny. Further faulting and folding, particularly in the south of the park is associated with the Variscan orogeny.