Graig Goch is a 586m 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
Gwynedd
Gwynedd (; ) is a county and preserved county (latter with differing boundaries; includes the Isle of Anglesey) in the north-west of Wales. It shares borders with Powys, Conwy County Borough, Denbighshire, Anglesey over the Menai Strait, and C ...
area in
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 ...
and lying within
Snowdonia National Park
Snowdonia or Eryri (), is a mountainous region in northwestern Wales and a national park of in area. It was the first to be designated of the three national parks in Wales, in 1951.
Name and extent
It was a commonly held belief that the nam ...
. The hill falls within the
communities
A community is a Level of analysis, social unit (a group of living things) with commonality such as place (geography), place, Norm (social), norms, religion, values, Convention (norm), customs, or Identity (social science), identity. Communiti ...
of
Llanfihangel-y-Pennant and
Corris
Corris is a village in the county of Gwynedd, Wales, about north of the town of Machynlleth. The village lies on the west bank of the Afon Dulas (which here forms the boundary with Powys), around that river's confluence with the Afon Deri. Its ...
, the summit being located in the former. The hill takes the form of a NE-SW aligned ridge with a broad top which rise to subsidiary tops either side of the main summit. These are the 540m+ top of Mynydd Cedris (OS grid ref SH 707080) and the 504m top of Mynydd Rugog (OS grid ref SH 722092). The hill’s most notable feature is the large cliff which stretches the length of its northwestern face overlooking
Tal-y-llyn, in part a major rock-slope failure.
Geology
The hill is formed from a succession of
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 and
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.Blatt ''et al.'' 1980, p ...
s laid down by
turbidity currents
A turbidity current is most typically an underwater current of usually rapidly moving, sediment-laden water moving down a slope; although current research (2018) indicates that water-saturated sediment may be the primary actor in the process. T ...
during the
Ordovician
The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start ...
Period. The main ridge is developed in rocks of the
Ceiswyn Formation assigned to the
Ogwen Group and dating from around 457 to 454 million years ago. A near vertical
cleavage is developed in the steeply southeasterly dipping strata.
Talus slopes (scree) lie beneath the main cliff, the massive landslip of part of which some time after the last ice age blocked the valley and is responsible for the presence of
Tal-y-llyn Lake
Tal-y-llyn Lake, ( cy, Llyn Mwyngil), also known as Talyllyn Lake and Llyn Myngul, is a large glacial ribbon lake in Gwynedd, North Wales. It is formed by a post-glacial massive landslip damming up the lake within the glaciated valley. The hamle ...
. The lake occupies a deep
glacial trench excavated along the line of the Tal-y-llyn Fault.
Access
Other than the afforested parts of its southern slopes and parts of its lowermost northern slopes, the entire hill is mapped as
open country
"Open Country" is a designation used for some UK access land.
It was first defined under the National Parks and Access to the Countryside Act 1949 (and extended by the Countryside Act 1968), and was land over which an appropriate access agreeme ...
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 ...
thereby giving the public extensive rights to wander at will across it. There are no recorded
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 ...
on the hill.
[Ordnance Survey Explorer map OL23 ''Cadair Idris & Llyn Tegid'']
References
{{reflist
External links
images of Graig Goch and area on Geograph website
Mountains and hills of Snowdonia