Mynydd Eglwysilan is a 355-metre-high
hill
A hill is a landform that extends above the surrounding terrain. It often has a distinct summit, and is usually applied to peaks which are above elevation compared to the relative landmass, though not as prominent as Mountain, mountains. Hills ...
in the
Caerphilly
Caerphilly (, ; , ) is a town and community (Wales), community in Wales. It is situated at the southern end of the Rhymney Valley and separated from the Cardiff suburbs of Lisvane and Rhiwbina by Caerphilly Mountain.
It is north of Cardiff an ...
county borough in South
Wales
Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic ...
3 km to the south of
Nelson
Nelson may refer to:
Arts and entertainment
* ''Nelson'' (1918 film), a historical film directed by Maurice Elvey
* ''Nelson'' (1926 film), a historical film directed by Walter Summers
* ''Nelson'' (opera), an opera by Lennox Berkeley to a lib ...
and a similar distance southwest of
Ystrad Mynach
Ystrad Mynach is a town in the Rhymney Valley in the Caerphilly County Borough, within the ancient county of Glamorgan, Wales, and is north of the town of Caerphilly. The urban area had a population of 19,204 in 2011. Before the Industrial Revo ...
. To its south is
Senghenydd
Senghenydd (, ) is a former mining village in the community of Aber Valley in South Wales, approximately four miles northwest of the town of Caerphilly. Historically within the county of Glamorgan, it is now situated in the county borough of Cae ...
at the head of the
Aber Valley
Aber Valley is a valley community in Caerphilly county borough, South Wales. It has two main communities, Abertridwr and Senghenydd, which grew around the mining industry in the late 19th and early 20th centuries. Senghenydd has a longer histor ...
. Like neighbouring
Cefn Eglwysilan, the hill is named after the hamlet of
Eglwysilan Eglwysilan is an ecclesiastical parish and Hamlet (place), hamlet in Wales, within the Community (Wales), community of Aber Valley in the unitary authority of Caerphilly County Borough.
History of the parish
During the 12th-century Norman inva ...
4 km to the southwest, the church here being dedicated to an obscure Saint Ilan. Remains of a linear
earthwork known as
Senghenydd Dyke stretch across the southern side of the hill. It is considered to mark the edge of an extensive
13th-century deer park associated with nearby
Caerphilly Castle
Caerphilly Castle () is a medieval castle, fortification in Caerphilly in South Wales. The castle was constructed by Gilbert de Clare, 7th Earl of Gloucester, Gilbert de Clare in the 13th century as part of his campaign to maintain control of ...
.
Geology
The hill is formed from the Hughes
Sandstone
Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
(formally the ‘Hughes Member’ and formerly the ‘Hughes Beds’) of the
Pennant Sandstone Formation laid down late in the
Carboniferous
The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...
Period (c. 309–306 million years ago).
Siltstone
Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.
Although its permeabil ...
s and
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.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...
s appear beneath the main upper bed of sandstone.
Access
The summit area of the hill is mapped as
open access
Open access (OA) is a set of principles and a range of practices through which nominally copyrightable publications are delivered to readers free of access charges or other barriers. With open access strictly defined (according to the 2001 de ...
under the
Countryside and Rights of Way Act 2000
The Countryside and Rights of Way Act 2000 (c. 37), also known as the CRoW Act and "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 impleme ...
thereby giving walkers freedom to explore it on foot. There are additionally a couple of
byways which traverse the eastern and southern margins of the summit plateau. The unfenced minor public road from Nelson to Senghenydd runs along the northwestern margin of the hill. A rough track passes by the
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 station is usually set up by a map ...
which marks the summit.
[Ordnance Survey Explorer map 166 '' Rhondda & Merthyr Tydfil/Merthyr Tudful'']
References
{{reflist
External links
images of Mynydd Eglwysilan and area on Geograph website
Mountains and hills of Caerphilly County Borough