Fan y Big (Welsh: ) is a subsidiary summit of

Waun Rydd Waun Rydd is a mountain in the Brecon Beacons National Park, in southern Powys, Wales. Its height is 769 m (2,523 ft) and it tops a large boggy plateau rising to the east of Pen y Fan.Nuttall, John & Anne (1999). The Mountains of ...

in the

Brecon Beacons National Park The Brecon Beacons National Park ( cy, Parc Cenedlaethol Bannau Brycheiniog) is one of three national parks in Wales, and is centred on the Brecon Beacons range of hills in southern Wales. It includes the Black Mountain (range), Black Mountain ...

, in southern

Powys Powys (; ) is a Local government in Wales#Principal areas, county and Preserved counties of Wales, preserved county in Wales. It is named after the Kingdom of Powys which was a Welsh succession of states, successor state, petty kingdom and princi ...

Wales Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...

. It is high and is often hiked as part of the Horseshoe Walk, a traverse of the four main peaks in the Brecon Beacons.

The hill

At , Fan y Big lies at the western tip of the

Gwaun Cerrig Llwydion Bwlch y Ddwyallt is the name commonly applied to the high point of the plateau of Gwaun Cerrig Llwydion in the eastern part of the Brecon Beacons in south Wales. It is a top of Waun Rydd. The plateau reaches its highest point of 754m above sea ...

plateau. Its name translates as 'point of the peak' - perhaps in allusion to its striking pointed shape, as seen from some directions. The summit is smooth and grassy, but marked by a cairn, which stands on the edge of its precipitous western face. The view of this face from

Cribyn Cribyn is a small village in Ceredigion, Wales, about 7 miles (11 km) north of Lampeter and with the villages of Troed y Rhiw, Mydroilyn and Dihewyd to the north. History and amenities Once a thriving community with two Public house, pubs, ...

is regarded as very striking. Fan y Big has since lost its status as a Hewitt.

Access

The peak is prominent on the north facing escarpment of the central part of the

Brecon Beacons The Brecon Beacons ( cy, Bannau Brycheiniog, ) are a mountain range in South Wales. In a narrow sense, the name refers to the range of Old Red Sandstone peaks which lie to the south of Brecon. Sometimes referred to as "the central Beacons" t ...

and three footpaths meet at the summit. All the surrounding land is open access and so walkers can go where they wish. In poor weather however, the paths are the safest route for access. The peak is often crossed by hikers aiming for

Pen y Fan Pen y Fan () is the highest peak in South Wales, situated in the Brecon Beacons National Park. At above sea-level, it is also the highest British peak south of Cadair Idris in Snowdonia. It is the highest point (county top) of the historic cou ...

and

Corn Du Corn Du is a summit of the twin topped Pen y Fan and the second highest peak in South Wales at 873 m (2,864 ft), situated in the Brecon Beacons National Park. The summit itself is marked by a well structured Bronze Age cairn with a cen ...

, and also forms part of the

Fan dance In the West, a fan dance (i.e., a dance performed with fans) may be an erotic dance performance, traditionally by a woman, but not exclusively. Beyond eroticism it is a form of musical interpretation. The performer, sometimes entirely nude o ...

, or Horseshoe Walk, a circular route that traverses four peaks.

Geology

In common with other peaks of the Brecon Beacons, the upper slopes of Fan y Big are formed from

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

s of the Brownstones Formation of the

Old Red Sandstone The Old Red Sandstone is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the northeastern seaboard of North America. It also exte ...

laid down during the

Devonian period The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, wh ...

. The lower slopes of the hill are formed from sandstones and

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...

s of the underlying Senni Formation. The

rock strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ei ...

tilt gently southwards. The valleys to the northwest and east nurtured small glaciers during the last

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...

. This

glacial erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

resulted in the very steep northern face which the mountain possesses.

References

{{reflist Brecon Beacons Mountains and hills of Powys Nuttalls