Corn Du is a summit of the twin topped

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 the second highest peak in

South Wales South Wales ( cy, De Cymru) is a loosely defined region of Wales bordered by England to the east and mid Wales to the north. Generally considered to include the historic counties of Glamorgan and Monmouthshire, south Wales extends westwards ...

at 873 m (2,864 ft), situated 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 ...

. The summit itself is marked by a well structured

Bronze Age The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second pri ...

cairn A cairn is a man-made pile (or stack) of stones raised for a purpose, usually as a marker or as a burial mound. The word ''cairn'' comes from the gd, càrn (plural ). Cairns have been and are used for a broad variety of purposes. In prehis ...

with a central burial

cist A cist ( or ; also kist ; from grc-gre, κίστη, Middle Welsh ''Kist'' or Germanic ''Kiste'') is a small stone-built coffin-like box or ossuary used to hold the bodies of the dead. Examples can be found across Europe and in the Middle East ...

like that on nearby Pen y Fan. The two summits are visible from great distances owing to their height above the surrounding

moorland Moorland or moor is a type of habitat found in upland areas in temperate grasslands, savannas, and shrublands and montane grasslands and shrublands biomes, characterised by low-growing vegetation on acidic soils. Moorland, nowadays, generally ...

, and are famous

landmark A landmark is a recognizable natural or artificial feature used for navigation, a feature that stands out from its near environment and is often visible from long distances. In modern use, the term can also be applied to smaller structures or f ...

s. The views from the peaks are also panoramic and very extensive, the Black Mountain and

Fforest Fawr 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 cat ...

being especially obvious to the west.

Mynydd Epynt Mynydd Epynt () is a former community and upland area in Powys, Wales. The Ministry of Defence controversially evicted the community of Mynydd Epynt in 1940, creating what is now the core of the Sennybridge Training Area (SENTA), the largest mil ...

is visible to the north behind the county town of

Brecon Brecon (; cy, Aberhonddu; ), archaically known as Brecknock, is a market town in Powys, mid Wales. In 1841, it had a population of 5,701. The population in 2001 was 7,901, increasing to 8,250 at the 2011 census. Historically it was the coun ...

, and other parts of the escarpment to the east.

Access

The summit is often crossed on the way to Pen y Fan, and forms part of a well-known circuit of the Beacons. It offers good views down into Cwm Llwch and across the Usk valley to

as well as east towards the

Sugar Loaf, Monmouthshire Sugar Loaf, sometimes called The Sugar Loaf ( cy, Mynydd Pen-y-fâl or ), is a hill situated north-west of Abergavenny in Monmouthshire, Wales and sits within the Brecon Beacons National Park. It is the southernmost of the summit peaks of the ...

above

Abergavenny Abergavenny (; cy, Y Fenni , archaically ''Abergafenni'' meaning "mouth of the River Gavenny") is a market town and community in Monmouthshire, Wales. Abergavenny is promoted as a ''Gateway to Wales''; it is approximately from the border wi ...

.Nuttall, John & Anne (1999). The Mountains of England & Wales - Volume 1: Wales (2nd edition ed.). Milnthorpe, Cumbria: Cicerone. . Tommy Jones' Obelisk is found on its western flanks, in between the summit and

Y Gyrn Y Gyrn is a top of Pen y Fan in South Wales, situated in the Brecon Beacons National Park. Tommy Jones' Obelisk is found in between the summit and Corn Du Corn Du is a summit of the twin topped Pen y Fan and the second highest peak in South ...

. All of the surrounding

is open to access, but crossing some parts of the terrain such as

peat bog A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and muskeg; a ...

s is more difficult and the main paths are well-engineered and maintained by the

National Trust The National Trust, formally the National Trust for Places of Historic Interest or Natural Beauty, is a charity and membership organisation for heritage conservation in England, Wales and Northern Ireland. In Scotland, there is a separate and ...

Geology

The summit is very similar to that of Pen y Fan: flat and anvil-shaped. It is similarly formed from the relatively erosion-resistant

Devonian 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, whe ...

age sandstones from the Upper

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 ...

known as the Plateau Beds. 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 ...

are clearly visible at the edge of the escarpment, where they form a resistant edge to the cliff. The same strata are visible all along the escarpment facing north, as well as the rearward edge facing south-east and lying behind the main peaks. The same Plateau Beds recur in the

Black Mountain (range) The Black Mountain ( cy, Y Mynydd Du) is a mountain range in South, Mid and West Wales, straddling the county boundary between Carmarthenshire and Powys (formerly Brecknockshire) and forming the westernmost range of the Brecon Beacons National ...

to the west, and cap the summits of

Picws Du Picws Du is the second highest peak of the Carmarthen Fans (or, in Welsh ''Bannau Sir Gâr'') in the Carmarthenshire section of the Black Mountain in the west of the Brecon Beacons National Park in south Wales. The highest peak is Fan Foel ...

and

Fan Foel Fan commonly refers to: * Fan (machine), a machine for producing airflow, often used for cooling ** Hand fan, an implement held and waved by hand to move air for cooling * Fan (person), short for fanatic; an enthusiast or supporter, especially wit ...

, as well as forming steep cliffs below the peaks. Tommy Jones Obelisk - geograph

Glacial lakes

Corn Du approached from the South - geograph

Nearby is one of the few natural lakes in the park, the small

Llyn Cwm Llwch Llyn Cwm Llwch () is a small lake or pool in the Brecon Beacons National Park in Powys, Wales. It is between 1 and 2 acres: much smaller than the two glacial lakes in the west of the Black Mountain (range): Llyn y Fan Fawr and Llyn y Fan Fach, an ...

. It may be compared with the much larger

glacial lake A glacial lake is a body of water with origins from glacier activity. They are formed when a glacier erodes the land and then melts, filling the depression created by the glacier. Formation Near the end of the last glacial period, roughly 10,0 ...

s of

Llyn y Fan Fach Llyn y Fan Fach (Welsh meaning "little lake (near) the peak") is a lake of approximately on the northern margin of the Black Mountain in Carmarthenshire, South Wales and lying within the Brecon Beacons National Park. The lake lies at an altitud ...

and

Llyn y Fan Fawr Llyn y Fan Fawr (Welsh: 'great lake (near) the peak') is a natural lake in the county of Powys, Wales. It lies at the foot of Fan Brycheiniog, the highest peak of the Black Mountain (Welsh''Y Mynydd Du'') range within the Brecon Beacons National ...

below the main ridge of the Black Mountain about 15 miles west of the central Brecon Beacons

escarpment An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. The terms ''scarp'' and ''scarp face'' are often used interchangeably with ''escar ...

. All three are of glacial origin and were formed 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 ...

by ice scouring out hollows below the peaks, the water being partly dammed by

moraine A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice shee ...

s of rock debris carried down by ice action subsequent to plucking and

frost shattering Frost weathering is a collective term for several mechanical weathering processes induced by stresses created by the freezing of water into ice. The term serves as an umbrella term for a variety of processes such as frost shattering, frost wedg ...

References

External links

Photos of Pen y Fan and surrounding area
{{coord, 51.88328, N, 3.43684, W, region:GB_source:enwiki-osgb36(SO012215), display=title Brecon Beacons Mountains and hills of Powys Tourist attractions in Powys Landmarks in Wales Hewitts of Wales Nuttalls Glyn Tarell