Mynydd Bach Trecastell
Encyclopedia
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 827312 at Y Pigwn. The name signifies the 'little hill of castle town'.
. The flaggy micaceous sandstones of the Tilestones Formation immediately overlies these beds and this is followed in turn by the thick sequence of the Raglan Mudstone Formation. These latter two formations are assigned as the oldest parts of the Old Red Sandstone
though date from the Silurian period. To the northwest are the various sandstones, mudstones and siltstones of the Aberedw, Hafod Fawr, Cwm Graig Ddu and Halfway Farm Formations. A series of northwest to southeast aligned faults cut through this succession and give rise to minor features in the landscape.
from CICVCIVM
(Brecon
) to MORIDVNVM
(Carmarthen
) via Llandovery
ran over the hill and evidence of a couple of Roman camps
and a Roman fortlet remains on the hill.
direction.
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...
and Powys
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...
in 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 Black Mountain region of 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...
. Its summit is plateau-like and reaches a height of 412m at OS grid ref SN 827312 at Y Pigwn. The name signifies the 'little hill of castle town'.
Geology
The summit of the hill is formed in sandstones and siltstones of the Cae'r Mynach Formation which like all of the rocks are tilted steeply to the southeast as part of a geological structure called 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 flaggy micaceous sandstones of the Tilestones Formation immediately overlies these beds and this is followed in turn by the thick sequence of the Raglan Mudstone Formation. These latter two formations are assigned as the oldest parts 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:...
though date from the Silurian period. To the northwest are the various sandstones, mudstones and siltstones of the Aberedw, Hafod Fawr, Cwm Graig Ddu and Halfway Farm Formations. A series of northwest to southeast aligned faults cut through this succession and give rise to minor features in the landscape.
Archaeology
There are several ancient cairns and a stone circle on Mynydd Bach Trecastell. The Roman roadRoman road
The Roman roads were a vital part of the development of the Roman state, from about 500 BC through the expansion during the Roman Republic and the Roman Empire. Roman roads enabled the Romans to move armies and trade goods and to communicate. The Roman road system spanned more than 400,000 km...
from CICVCIVM
Y Gaer, Brecon
Y Gaer, Brecon is a Roman fort situated near modern day Brecon in Mid Wales, United Kingdom.Y Gaer is located at .- History :...
(Brecon
Brecon
Brecon is a long-established market town and community in southern Powys, Mid Wales, with a population of 7,901. It was the county town of the historic county of Brecknockshire; although its role as such was eclipsed with the formation of Powys, it remains an important local centre...
) to MORIDVNVM
Moridunum (Carmarthen)
Moridunum was a Roman fort and town in the Roman province of Britannia. Today it is known as Carmarthen, located in the Welsh county of Carmarthenshire .-Fort:...
(Carmarthen
Carmarthen
Carmarthen is a community in, and the county town of, Carmarthenshire, Wales. It is sited on the River Towy north of its mouth at Carmarthen Bay. In 2001, the population was 14,648....
) via Llandovery
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...
ran over the hill and evidence of a couple of Roman camps
Castra
The Latin word castra, with its singular castrum, was used by the ancient Romans to mean buildings or plots of land reserved to or constructed for use as a military defensive position. The word appears in both Oscan and Umbrian as well as in Latin. It may have descended from Indo-European to Italic...
and a Roman fortlet remains on the hill.
Access
Mynydd Bach Trecastell is largely designated as open country and so freely accessible to walkers. The old Roman road provides access onto the hill from the TrecastleTrecastle
Trecastle is a village in Powys, Wales, on the edge of the Brecon Beacons National Park.Trecastle is named after an early 12th century motte-and-bailey fortification , built by Bernard de Neufmarche and designed to protect Brecon from attack from the west...
direction.