Mynydd Llangynidr
Encyclopedia
Mynydd Llangynidr is a hill in the Brecon Beacons National Park largely in the county of Powys
, south Wales
. Its southern slopes extend into the northernmost parts of the county borough
of Caerphilly
. It is named from the village of Llangynidr
which sits in the valley of the River Usk
to the north of it. It is essentially an undulating plateau rising in the west to a height of 557m at Garn Fawr at OS grid ref SO 123151. A secondary high point is achieved at a point marked by a trig point
at SO 147159. To the north the hill overlooks the valleys of Dyffryn Crawnon and Cwm Claisfer, themselves tributary valleys of the Usk. The shallow upper valley of the Ebbw River
reaches into the plateau in the south whilst the upper reaches of the Sirhowy Valley
and its tributary the Nant Trefil define its western margins. Passing east across the B4560, the hill merges with Mynydd Llangatwg
which has a similar character.
of Palaeozoic era sandstone
s and limestones which dip gently southwards into the South Wales Coalfield
basin. Broken cliffs of Carboniferous Limestone
occur along the northern edges and this rock underlies the entire hill. The plateau is formed from coarse sandstones ('gritstones') also dating from the Carboniferous period and which have foundered in many places as the underlying limestone has dissolved over millennia. The larger part of the hill has a pock-marked appearance due to the hundreds of shakeholes in its surface arising from the presence of the limestone beneath the sandstone cover. The most celebrated cave on Mynydd Llangynidr is Ogof Fawr or Chartist's Cave (so named as it was reputed to be a hiding place for the Chartist
s of South Wales), situated 500m to the east of the top of Garn Fawr.
whilst that at Blaen Onneu in the northeast has not been worked since the 1980s. There are also a few small quarries for limestone which predate the larger workings.
s on this tract of moorland, the most notable of which are Garn Fawr ('big cairn') and Carn Caws ('cheese cairn'). Other prehistoric cairns and a stone row together with evidence of house platform
s occur towards its northern edge.
to roam at will. There are few defined paths though two public footpaths cross from north to south from Llangynidr towards Tredegar
. The B4560 road from Garnllydan to Llangynidr cuts across the high moorland to the east of the hill and offers the easiest access to both Mynydd Llangynidr and to Mynydd Llangatwg to its east. To the west a minor road heads north from the A465 Heads of the Valleys Road through the small village of Trefil
and continues north as a bridleway, also offering easy access to the hill.
Powys
Powys is a local-government county and preserved county in Wales.-Geography:Powys covers the historic counties of Montgomeryshire and Radnorshire, most of Brecknockshire , and a small part of Denbighshire — an area of 5,179 km², making it the largest county in Wales by land area.It is...
, south Wales
Wales
Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...
. Its southern slopes extend into the northernmost parts of the county borough
County borough
County borough is a term introduced in 1889 in the United Kingdom of Great Britain and Ireland , to refer to a borough or a city independent of county council control. They were abolished by the Local Government Act 1972 in England and Wales, but continue in use for lieutenancy and shrievalty in...
of Caerphilly
Caerphilly
Caerphilly is a town in the county borough of Caerphilly, south Wales, located at the southern end of the Rhymney Valley, with a population of approximately 31,000. It is a commuter town of Cardiff and Newport, which are located some 7.5 miles and 12 miles away, respectively...
. It is named from the village of Llangynidr
Llangynidr
Llangynidr is a village in Powys, Wales, about west of Crickhowell and south-east of Brecon. The River Usk flows through the village as does the Monmouthshire and Brecon Canal on which there are four locks....
which sits in the valley of the River Usk
River Usk
The River Usk rises on the northern slopes of the Black Mountain of mid-Wales, in the easternmost part of the Brecon Beacons National Park. Initially it flows north into Usk Reservoir, then east by Sennybridge to Brecon before turning southeast to flow by Talybont-on-Usk, Crickhowell and...
to the north of it. It is essentially an undulating plateau rising in the west to a height of 557m at Garn Fawr at OS grid ref SO 123151. A secondary high point is achieved at a point marked by a trig point
Trig point
A triangulation station, also known as a triangulation pillar, trigonometrical station, trigonometrical point, trig station, trig beacon or trig point, and sometimes informally as a trig, is a fixed surveying station, used in geodetic surveying and other surveying projects in its vicinity...
at SO 147159. To the north the hill overlooks the valleys of Dyffryn Crawnon and Cwm Claisfer, themselves tributary valleys of the Usk. The shallow upper valley of the Ebbw River
Ebbw River
The Ebbw River is a river in South Wales.The main Ebbw River is formed by the confluence of the two minor Ebbw rivers, Ebbw Fach, and Ebbw Fawr ....
reaches into the plateau in the south whilst the upper reaches of the Sirhowy Valley
Sirhowy Valley
The Sirhowy Valley is an industrialised valley in the eastern part of the Valleys region of South Wales. It is named from the Sirhowy River which runs through it. Its upper reaches are occupied by the town of Tredegar within the unitary area of Blaenau Gwent...
and its tributary the Nant Trefil define its western margins. Passing east across the B4560, the hill merges with Mynydd Llangatwg
Mynydd Llangatwg
Mynydd Llangatwg or Llangattock Mountain is a hill in the Brecon Beacons National Park in the county of Powys, south Wales. It is named from the village of Llangatwg which sits in the valley of the River Usk to the north of it...
which has a similar character.
Geology
Mynydd Llangynidr is formed from a layer cakeGeology of South Wales
South Wales is an area with many features of outstanding interest to geologists, who have for long used the area for University field trips.This varied and accessible region has provided a written record of geological interest going back to the 1100s when Giraldus Cambrensis noted pyritous shales...
of Palaeozoic era sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
s and limestones which dip gently southwards into the South Wales Coalfield
South Wales Coalfield
The South Wales Coalfield is a large region of south Wales that is rich with coal deposits, especially the South Wales Valleys.-The coalfield area:...
basin. Broken cliffs of Carboniferous Limestone
Carboniferous limestone
Carboniferous Limestone is a term used to describe a variety of different types of limestone occurring widely across Great Britain and Ireland which were deposited during the Dinantian epoch of the Carboniferous period. They were formed between 363 and 325 million years ago...
occur along the northern edges and this rock underlies the entire hill. The plateau is formed from coarse sandstones ('gritstones') also dating from the Carboniferous period and which have foundered in many places as the underlying limestone has dissolved over millennia. The larger part of the hill has a pock-marked appearance due to the hundreds of shakeholes in its surface arising from the presence of the limestone beneath the sandstone cover. The most celebrated cave on Mynydd Llangynidr is Ogof Fawr or Chartist's Cave (so named as it was reputed to be a hiding place for the Chartist
Chartism
Chartism was a movement for political and social reform in the United Kingdom during the mid-19th century, between 1838 and 1859. It takes its name from the People's Charter of 1838. Chartism was possibly the first mass working class labour movement in the world...
s of South Wales), situated 500m to the east of the top of Garn Fawr.
Quarrying
A couple of major limestone quarries intrude upon the hill. There is an active quarry at TrefilTrefil
Trefil is a small village in the county borough of Blaenau Gwent, south Wales. It lies at the top of the Sirhowy Valley, three miles northwest of Tredegar...
whilst that at Blaen Onneu in the northeast has not been worked since the 1980s. There are also a few small quarries for limestone which predate the larger workings.
Archaeology
There are numerous ancient cairnCairn
Cairn is a term used mainly in the English-speaking world for a man-made pile of stones. It comes from the or . Cairns are found all over the world in uplands, on moorland, on mountaintops, near waterways and on sea cliffs, and also in barren desert and tundra areas...
s on this tract of moorland, the most notable of which are Garn Fawr ('big cairn') and Carn Caws ('cheese cairn'). Other prehistoric cairns and a stone row together with evidence of house platform
Earthworks (archaeology)
In archaeology, earthwork is a general term to describe artificial changes in land level. Earthworks are often known colloquially as 'lumps and bumps'. Earthworks can themselves be archaeological features or they can show features beneath the surface...
s occur towards its northern edge.
Access
The hill is mapped as open country and therefore freely available for walkersHillwalking
In the British Isles, the terms hillwalking or fellwalking are commonly used to describe the recreational outdoor activity of walking on hills and mountains, often with the intention of visiting their summits...
to roam at will. There are few defined paths though two public footpaths cross from north to south from Llangynidr towards Tredegar
Tredegar
Tredegar is a town situated on the Sirhowy River in the county borough of Blaenau Gwent, in south-east Wales. Located within the historic boundaries of Monmouthshire, it became an early centre of the Industrial Revolution in South Wales...
. The B4560 road from Garnllydan to Llangynidr cuts across the high moorland to the east of the hill and offers the easiest access to both Mynydd Llangynidr and to Mynydd Llangatwg to its east. To the west a minor road heads north from the A465 Heads of the Valleys Road through the small village of Trefil
Trefil
Trefil is a small village in the county borough of Blaenau Gwent, south Wales. It lies at the top of the Sirhowy Valley, three miles northwest of Tredegar...
and continues north as a bridleway, also offering easy access to the hill.