Mynydd Marchywel is a 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 ...
in the Neath Port Talbot area 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 ...
. Its summit is marked both by a cairn and a
trig point
A triangulation station, also known as a trigonometrical point, and sometimes informally as a trig, is a fixed surveying station, used in geodetic surveying and other surveying projects in its vicinity. The nomenclature varies regionally: they a ...
. The larger part of the hill is cloaked in modern forestry through which numerous streams fall away westward to the
River Tawe
The River Tawe (; cy, Afon Tawe ) is a long river in South Wales. Its headwaters flow initially east from its source below Llyn y Fan Fawr south of Moel Feity in the Black Mountains, the westernmost range of the Brecon Beacons National Pa ...
, eastward to the
River Dulais
River Dulais ( cy, Afon Dulais) is a river of Wales which has its source at Mynydd y Drum. It joins the River Neath after flowing over Aberdulais Falls
The Aberdulais Falls are found on the River Dulais at Aberdulais, near Neath in the county ...
and southward into the
Clydach, the latter two being tributaries of the
River Neath
River Neath ( cy, Afon Nedd) is a river in south Wales running south west from the point at which its headwaters arising in the Brecon Beacons National Park converge to its mouth at Baglan Bay below Briton Ferry on the east side of Swansea Bay. ...
.
Geology
The hill is formed from multiple layers of
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 ...
with 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. ...
layers and occasional
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. All are tilted to the south and southwest 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 ...
. Parts of its slopes are mantled by
glacial till
image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...
. The coal seams have been worked extensively in the past. One of the last operations was that at
Gleision Colliery The Tarenni Colliery ( cy, Gloddfa Tarenni) and its associated workings, are a series of coal mines and pits located between the villages of Godre'r Graig and Cilybebyll located in the valley of the River Tawe, in Neath Port Talbot county borough, S ...
under the northwestern side of Mynydd Marchywel.
Scheduled monuments
;Mynydd Marchywel summit cairn: This
Round cairn
A bowl barrow is a type of burial mound or tumulus. A barrow is a mound of earth used to cover a tomb. The bowl barrow gets its name from its resemblance to an upturned bowl. Related terms include ''cairn circle'', ''cairn ring'', ''howe'', ''ker ...
dating to 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 ...
is north of the trig pont. The heap of stones, now gradually spreading, has traces of kerbstones amongst the rubble.
;Tirlan medieval house sites: (, OS grid ref:SN762026). The earthwork remains of two medieval platform houses, apart, are beside a track on the south-east flank of Mynnydd Marchywel, near Tyrlan. Cultivation ridges are also in the vicinity.
Access
Mynydd Marchywel is crossed by
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.
...
which locally runs from
Ynysmeudwy to
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 ...
across the northern slopes of the hill, following one of the very few
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 ...
to be found on the hill. There are however numerous forest tracks and most of its western flanks, including the summit area, are designated 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 ...
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 ...
.
[Ordnance Survey Explorer map 165 ''Swansea'']
See also
*
List of Scheduled Monuments in Neath Port Talbot
References
{{reflist
External links
images of Mynydd Marchywel and area on Geograph website
Mountains and hills of Neath Port Talbot
Marilyns of Wales