Hirfynydd is a 481-metre-high

hill A hill is a landform that extends above the surrounding terrain. It often has a distinct Summit (topography), summit. Terminology The distinction between a hill and a mountain is unclear and largely subjective, but a hill is universally con ...

Neath Port Talbot Neath Port Talbot ( cy, Castell-nedd Port Talbot) is a Local government in Wales#Principal areas, county borough in the South West Wales, south-west of Wales. Its principal towns are Neath, Port Talbot, Briton Ferry and Pontardawe. The county bor ...

county borough in South

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 ...

. A Roman road,

Sarn Helen Sarn Helen refers to several stretches of Roman road in Wales. The route, which follows a meandering course through central Wales, connects Aberconwy in the north with Carmarthen in the west. Despite its length, academic debate continues as t ...

, runs along its entire northeast–southwest ridge-line, a route followed by a modern-day byway. To its west is Cwm Dulais and to its southeast is the

Vale of Neath The Vale of Neath (or Neath Valley, Welsh: ''Cwm Nedd''), one of the South Wales Valleys, encompasses the upper reaches of the River Neath in southwest Wales. In addition to the River Neath, it is traversed by the Neath Canal and the A465 dual ...

. The northern end of the ridge falls away to a broad upland vale containing the

Afon Pyrddin The Afon Pyrddin is a river forming a short section of the boundary between the counties of Brecknockshire and Glamorgan in Wales, Great Britain. It also forms a part of the boundary of the Brecon Beacons National Park, and the boundary of the unit ...

and beyond which is 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 larger part of the hill is afforested with

conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ...

s. In between the plantations are areas of past or present opencasting for

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dea ...

Geology

The upper parts of the hill are formed from the hard-wearing

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 and intervening

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

Pennant Sandstone The Pennant Measures is the traditional name for a sequence of sedimentary rocks of the South Wales Coalfield. They were also referred to as the Upper Coal Measures and assigned to the Westphalian 'C' and Westphalian 'D' stages of the Carbonifero ...

. Beneath these are the mudstones and

coal seam Coal mining is the process of extracting coal from the ground. Coal is valued for its energy content and since the 1880s has been widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from ...

s of the South Wales Coal Measures. All the strata are tilted in a generally southerly direction towards the axis of the

South Wales Coalfield The South Wales Coalfield ( cy, Maes glo De Cymru) extends across Pembrokeshire, Carmarthenshire, Swansea, Neath Port Talbot, Bridgend, Rhondda Cynon Taf, Merthyr Tydfil, Caerphilly, Blaenau Gwent and Torfaen. It is rich in coal deposits, espec ...

syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimpose ...

though there is significant local variation, due in part to the proximity of the eastern slopes of the hill to the

Neath Disturbance The Neath Disturbance is a geological structure which stretches across south Wales from Swansea Bay northeastwards as far as Hereford in western England. It consists of a series of both faults and associated folds which were active during the mo ...

Burial cairn

The

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 ...

Carn Cornel Round Cairn is on the shoulder of hillside, west of the ridge and Roman road. (Location: , OS grid ref: SN816062.) It is a pile of stones marking a burial, and occupies what appears to be a natural mound. Close by is a boundary stone, suggesting that the site became a historic boundary mark.

Roman Fortlet

On the top of the ridge, at a height of , is a small square earth-banked enclosure, 18x19 metres, with rounded corners. (location: ). This is a Roman fortlet, or

Castellum A ''castellum'' in Latin is usually: * a small Roman fortlet or tower,C. Julius Caesar, Gallic War; 2,30 a diminutive of ('military camp'), often used as a watchtower or signal station like on Hadrian's Wall. It should be distinguished from a ...

, used to both control the Carmarthen to Brecon

Roman road, and provide a signal station with wide visibility to the surrounding area. The enclosure is a

Scheduled Ancient Monument In the United Kingdom, a scheduled monument is a nationally important archaeological site or historic building, given protection against unauthorised change. The various pieces of legislation that legally protect heritage assets from damage and d ...

Medieval settlement

There are a group of medieval house platforms on the edge of a plateau of the Hirfynydd ridge, beside the steep slopes of the Dulais valley, showing where a settlement had been. (Location: , OS grid ref: SN806063). A banked rectangular enclosure has a house platform in the west corner. Two further platforms are west of the enclosure. The site is a Scheduled monument and is also called Coed Ddu and Nant-y-Cafn enclosure.

Access

Parts of the hill are available as

open access Open access (OA) is a set of principles and a range of practices through which research outputs are distributed online, free of access charges or other barriers. With open access strictly defined (according to the 2001 definition), or libre op ...

for walkers under the

Countryside and Rights of Way Act 2000 The Countryside and Rights of Way Act 2000 (c. 37), known informally as the CRoW Act or "Right to Roam" Act is a United Kingdom Act of Parliament affecting England and Wales which came into force on 30 November 2000. Right to roam The Act imp ...

. In addition there are numerous forest tracks which provide access and

public rights of way Right of way is the legal right, established by grant from a landowner or long usage (i.e. by prescription), to pass along a specific route through property belonging to another. A similar ''right of access'' also exists on land held by a gov ...

in some areas.

Saint Illtyd's Walk Saint Illtyd's Walk is a waymarked long-distance footpath in South Wales. It runs from Pembrey Country Park, west of Burry Port, through rural eastern Carmarthenshire and Neath Port Talbot to end at Margam Country Park, south of Port Talbot. ...

, a recreational walking trail follows a public bridleway to pass over Hirfynydd between

Crynant Crynant ( cy, Y Creunant) is a village and community in the Dulais Valley in Wales. It lies 7¾ miles north-east from the town of Neath in Neath Port Talbot, situated between the mountains of Mynydd Marchywel to the west, Hirfynydd to the east a ...

and

Resolven Resolven ( cy, Resolfen) is a small village and community in Neath Port Talbot county borough, Wales. It is located in the Vale of Neath. Location The village is situated in the Vale of Neath, north east of the town of Neath, next to the A465 ...

.Ordnance Survey Explorer map 165 ''Swansea/Abertawe''

References

{{reflist

External links

images of Hirfynydd and area on Geograph website

Hirfynydd Roman Fortlet - Roman Britain
Mountains and hills of Neath Port Talbot Marilyns of Wales