Mynydd Myddfai
Encyclopedia
Mynydd Myddfai is a hill 4.5 miles southeast of Llandovery
in the county of Carmarthenshire
, southwest Wales
. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark
. The hill is in the form of a broad ridge aligned southwest to northeast with three or four distinct tops separated by col
s. The northwest side drops steeply away towards the village of Myddfai
whilst the other side is a more shallow slope down towards Glasfynydd Forest
which encircles Usk Reservoir
. The plateau surface of the hill rises to a height of 440m at OS grid ref SN 806297 where a trig point
has been erected.
. The summit ridge is formed from sandstones and mudstones of the Cae'r Mynach Formation. Immediately southeast of these beds is the narrow band of the Tilestones Formation along which are a line of grassed over diggings left after these flaggy micaceous sandstones were extracted for use as roof tiles. Southeast again is the thick sequence of the Raglan Mudstone Formation.These last two formations are considered to be the lowermost of the Old Red Sandstone
sequence though assigned like the rest of the rocks forming Mynydd Myddfai to the Silurian period. Northwest of the summit ridge are the sandstones and siltstones of the Hafod Fawr Formation and beneath them more sandstones, mudstones and siltstones of the Cwm Craig Ddu and Halfway Farm Formations. Northwest to southeast oriented faults cross the ridge in places and can be seen where they offset the line of the Tilestones workings.
s on the hill together with the line of old quarries mentioned above. The age of these workings is unknown though they may well have been active over an extended period. A variety of Roman
remains are located on Mynydd Bach Trecastell
just to the northeast of Mynydd Myddfai. A number of new archaeological finds in 2007/08 were made during the excavation of a deep trench across the northern end of Mynydd Myddfai for the laying of a controversial gas pipeline from Milford Haven
to Tirley in Gloucestershire.
northwest to Cwm yr Olchfa and another runs southeast from this one to meet a minor public road at the west end of the hill.
Llandovery
Llandovery is a market town in Carmarthenshire, Wales, lying on the River Tywi and the A40 road.The town is served by Llandovery railway station, where there is a park and ride to Llanelli and Shrewsbury via the Heart of Wales Line...
in the county of Carmarthenshire
Carmarthenshire
Carmarthenshire is a unitary authority in the south west of Wales and one of thirteen historic counties. It is the 3rd largest in Wales. Its three largest towns are Llanelli, Carmarthen and Ammanford...
, southwest 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...
. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark
Fforest Fawr Geopark
Fforest Fawr Geopark was the first Geopark to be designated 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...
. The hill is in the form of a broad ridge aligned southwest to northeast with three or four distinct tops separated by col
Mountain pass
A mountain pass is a route through a mountain range or over a ridge. If following the lowest possible route, a pass is locally the highest point on that route...
s. The northwest side drops steeply away towards the village of Myddfai
Myddfai
Myddfai is a small village and community in Carmarthenshire, Wales. It is situated south of Llandovery in the Brecon Beacons, and has a population of 415.-Lady of the Lake Legend:...
whilst the other side is a more shallow slope down towards Glasfynydd Forest
Glasfynydd Forest
Glasfynydd Forest is an extensive area of coniferous plantations in the west of the Brecon Beacons National Park in south Wales. It straddles the border between the counties of Powys and Carmarthenshire....
which encircles Usk Reservoir
Usk Reservoir
The Usk Reservoir is located in the upper Usk Valley, at above sea level, in Carmarthenshire, south Wales.The reservoir is situated in part of the Brecon Beacons National Park.Completed in 1955, it now covers some of land...
. The plateau surface of the hill rises to a height of 440m at OS grid ref SN 806297 where 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...
has been erected.
Geology
The hill is composed of a variety of different rock formations all tilted steeply to the southeast in a structure known as the Myddfai Steep BeltMyddfai Steep Belt
The Myddfai Steep Belt is the name given to a geological structure which affects rocks of Silurian and Devonian age in mid Wales. It extends for tens of miles across country from near Carmarthen northeastwards via Mynydd Myddfai, Mynydd Bach Trecastell and Mynydd Epynt to the vicinity of...
. The summit ridge is formed from sandstones and mudstones of the Cae'r Mynach Formation. Immediately southeast of these beds is the narrow band of the Tilestones Formation along which are a line of grassed over diggings left after these flaggy micaceous sandstones were extracted for use as roof tiles. Southeast again is the thick sequence of the Raglan Mudstone Formation.These last two formations are considered to be the lowermost of the Old Red Sandstone
Old Red Sandstone
The Old Red Sandstone is a British rock formation of considerable importance to early paleontology. For convenience the short version of the term, 'ORS' is often used in literature on the subject.-Sedimentology:...
sequence though assigned like the rest of the rocks forming Mynydd Myddfai to the Silurian period. Northwest of the summit ridge are the sandstones and siltstones of the Hafod Fawr Formation and beneath them more sandstones, mudstones and siltstones of the Cwm Craig Ddu and Halfway Farm Formations. Northwest to southeast oriented faults cross the ridge in places and can be seen where they offset the line of the Tilestones workings.
Archaeology
There are several 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 the hill together with the line of old quarries mentioned above. The age of these workings is unknown though they may well have been active over an extended period. A variety of Roman
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....
remains are located on Mynydd Bach Trecastell
Mynydd Bach Trecastell
Mynydd Bach Trecastell is a hill on the border between the counties of Carmarthenshire and Powys in southwest Wales. It lies within the Black Mountain region of the Brecon Beacons National Park and Fforest Fawr Geopark. Its summit is plateau-like and reaches a height of 412m at OS grid ref SN...
just to the northeast of Mynydd Myddfai. A number of new archaeological finds in 2007/08 were made during the excavation of a deep trench across the northern end of Mynydd Myddfai for the laying of a controversial gas pipeline from Milford Haven
Milford Haven
Milford Haven is a town and community in Pembrokeshire, Wales. It is situated on the north side of the Milford Haven Waterway, a natural harbour used as a port since the Middle Ages. The town was founded in 1790 on the north side of the Waterway, from which it takes its name...
to Tirley in Gloucestershire.
Access
The hill is designated as open country and so freely accessible to walkers. A bridleway runs across it from the dam of the Usk ReservoirUsk Reservoir
The Usk Reservoir is located in the upper Usk Valley, at above sea level, in Carmarthenshire, south Wales.The reservoir is situated in part of the Brecon Beacons National Park.Completed in 1955, it now covers some of land...
northwest to Cwm yr Olchfa and another runs southeast from this one to meet a minor public road at the west end of the hill.