Black Mountain (range)
The Black Mountain is a mountain range in South and West Wales, straddling the county boundary between Carmarthenshire and Brecknockshire 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.
Name
The Black Mountain should not be confused with the Black Mountains in the east of the National Park, nor with a summit in the Black Mountains that is confusingly also called Black Mountain. In his description of a Blak Montayne, the antiquarian John Leland refers to a massif extending between Carmarthen and Monmouth i.e. what is now considered to be the Brecon Beacons in the wider modern sense of that term, thus also including the Black Mountains and the intervening high ground of Fforest Fawr.The term "Carmarthen Fans" is sometimes used inaccurately to describe the whole of this massif, whereas it should be restricted to the peaks along the northern escarpment within Carmarthenshire. The "Carmarthen Fans" thus includes Fan Foel, Picws Du and Waun Lefrith. The highest point of the "Carmarthen Fans" and the county top of Carmarthenshire is thus the minor summit of Fan Foel, height.
Geology
The range stretches approximately from Ammanford in the south-west to Sennybridge in the north-east. The larger part of these hills is formed from Old Red Sandstone, though bands of Carboniferous Limestone and of Twrch Sandstone are important landscape-forming rocks in the south and west of the range owing to their greater resistance to erosion. The most resistant of all are the Plateau beds, which form a protective cap over most of the range. They also form steep cliffs just below the edge of the escarpment. The rocks are of the Devonian, in common with their companion peaks of the Brecon Beacons to the east. The area was glaciated during the ice ages and a number of fresh moraines are to be found beneath the spectacular north and east facing sandstone scarps in the north-east of the range, especially below Fan Hir. There are smaller moraines lying immediately below the cliffs of Waun Lefrith and Picws Du., below Fan Brycheiniog in the Black Mountain
The lakes below the escarpment of Llyn y Fan Fawr and Llyn y Fan Fach are also remnants of glacial action, having been created by other moraines blocking drainage by forming deep hollows below the cliffs.
Archaeology
There are many surviving remains, especially prehistoric and Roman, in the area. They include the castras at Mynydd Bach Trecastell and a Roman road crossing Fforest Fawr as Sarn Helen. There are numerous menhirs, round barrows and several small stone circles. An especially famous circle occurs on the banks of the River Tawe below Fan Hir, and is known as Cerrig Duon, or "black stones". There is a standing stone outside the circle nearby, known as Maen Mawr, with two smaller stones forming a small avenue. There is also evidence of human settlements, hut circles and agriculture. Recent excavation of a cairn or round barrow on Fan Foel showed it to be of early Bronze Age in date and there is a very similar unexcavated round barrow on Picws Du. The excavation at Fan Foel indicated that the moorland was well-wooded in Bronze Age Britain owing to a warmer climate than at present, with much of the present moorland covered by hazel scrub with oak at lower heights. Most current moorland elsewhere in Britain was in a similar condition, and extensive Bronze Age remains have been found there too. Examples include Dartmoor, Exmoor, Bodmin Moor, much of the upland Pennines and upland Welsh moorland in the centre and north of the country. All such moorlands are tree-less in their upper parts, in their current sub-arctic state.Drainage
The massif is drained by a number of rivers which flow down the southern dip-slopes of the massif from its main ridge. In contrast the northerly directed streams tend to be shorter and steeper. The upper parts of the range are largely moorland and covered with peat bog, some of which is degrading judging by the partly destroyed sections of peat bank near Llyn y Fan Fawr. The rivers Usk and Tawe have their sources on the northern and eastern flanks of the range whilst the smaller Loughor arises at the western end of the range. Significant right bank tributaries of the Tawe such as the River Giedd and the Afon Twrch, as well as the River Amman, a tributary of the Loughor, are the principal southerly-directed watercourses. Two left-bank tributaries of the River Towy, the River Cennen and the Afon Sawdde, drain the northwestern slopes of the Black Mountain.The range is noted for its two large glacial lakes which sit directly below the main escarpment, being much larger than the small lake of similar origin which occurs below Pen y Fan.
Llyn y Fan Fach
is the smaller and more westerly of two natural lakes within the Black Mountain. It is enclosed within a rock hollow formed as a result of glacial action during the ice ages. It is about 500 yards long and 200 yards wide, and roughly oriented east-west. It is drained by the Afon Sawdde which cuts through a glacial moraine which in part forms a natural dam. A small artificial dam was constructed in the 1930s to divert some of its waters to boost Llanelli's water supply. Llyn y Fan Fach is associated with the Lady of the Lake legend.The lake can easily be reached by foot from the car park on the water board access road near Llanddeusant, although the road to the car park is poorly signposted, and in very poor condition for car travel.
Llyn y Fan Fawr
The lake Llyn y Fan Fawr or lake of the large peak, which lies below Fan Brycheiniog towards the eastern end of the mountain. It is of similar glacial origin to its westerly neighbour, but is slightly larger. It is about 600 yards long and 200 yards wide, being roughly oriented north south. It is drained by a stream known as Nant y Llyn, whose waters flow into the River Tawe. The surface of Llyn y Fan Fawr lies at about 1980 feet or 605 m above sea level.The lake can be reached on foot by an approximately 1.7 mile walk across the moor from the minor Trecastle to Abercraf road, where there is a small space for cars to park. There is another small car park a short distance away to the south and next to the same road at the end of another footpath to the lake.
Access
Parts of the massif are over 5 km or over 3 miles from the nearest public road. Indeed, those roads are mostly very minor single track roads with a few passing places, making the centre of the range even more inaccessible. There are several small car parks on the minor roads crossing the range, and a larger car park on the minor road from Llanddeusant village to the base of the access road to Llyn y Fan Fach. Virtually the entire massif consists of land mapped as open country and hence legally accessible to the public on foot under the provisions of the Countryside and Rights of Way Act 2000.In addition the range is crossed from north to south by a number of long bridleways which may be used by mountain bikers and horseriders though long sections of them are very rough and indistinct. The Beacons Way traverses the range roughly from east to west. Increased use of certain sections of path by walkers in recent years has resulted in accelerated erosion, a problem exacerbated by the sometimes thin, gravelly soils and the high rainfall, and has prompted repairs by the Brecon Beacons National Park Authority. There are numerous peat bogs on the high and middle ground, although some are bridged by stone pavements. There is a well graded stone staircase which carries the Beacons Way path from Llyn y Fan Fawr up the escarpment to Fan Brycheiniog in the centre of the range.