Craig Cerrig-gleisiad is a subsidiary summit of
Fan Fawr
Fan Fawr ( Welsh 'great peak') is a mountain in the Fforest Fawr section of the Brecon Beacons National Park, in Powys, Wales and over 734 m (2,408 ft) high.
The summit overlooks the steep eastern face and is marked by a cairn. Un ...
in the
Fforest Fawr
Fforest Fawr is an extensive upland area in the county of Powys, Wales. Formerly known as the Great Forest of Brecknock in English, it was a royal hunting area for several centuries but is now used primarily for sheep grazing, forestry, water cat ...
section of the
Brecon Beacons National Park
A national park is a nature park, natural park in use for conservation (ethic), conservation purposes, created and protected by national governments. Often it is a reserve of natural, semi-natural, or developed land that a sovereign state dec ...
,
South Wales
South Wales ( cy, De Cymru) is a loosely defined region of Wales bordered by England to the east and mid Wales to the north. Generally considered to include the historic counties of Glamorgan and Monmouthshire, south Wales extends westwards ...
. It makes up half of the
with its sister peak
Fan Frynych
Fan Frynych is the northernmost peak of the Fforest Fawr massif in the Brecon Beacons National Park, South Wales. It is classed as a subsidiary summit of Fan Fawr and makes up half of the Craig Cerrig-gleisiad and Fan Frynych National Nature Re ...
.
The summit is marked by a pile of stones, and sits on the edge of steep north facing cliffs which provide one of the few habitats for
Arctic–alpine
An Arctic–alpine taxon is one whose natural distribution includes the Arctic and more southerly mountain ranges, particularly the Alps. The presence of identical or similar taxa in both the tundra of the far north, and high mountain ranges much f ...
plants this far south in the
British Isles
The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles, ...
. To the south-west is
Fan Llia
Fan Llia is a subsidiary summit of Fan Fawr in the Fforest Fawr section of the Brecon Beacons National Park, Wales. In common with other peaks in the Fforest Fawr uplands it lies within the county of Powys.
The hill has the form of a broad ridg ...
.
Geology
The outstanding feature of the mountain is the L-shaped glacial
cwm which faces to the northeast. Its modern form is considered to be the result of a complex history of both
glacial
A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betw ...
action and rock-slope failure, a portion of the west wall having collapsed after the main part of the last ice age. Some of the debris was re-worked during the
Loch Lomond Stadial and parts stretch as far as the A470 road.
[Richard Shakesby, Classic Landforms of the Brecon Beacons, 2002, Geological Association Landform Guides series no 13] The rocks exposed in the main crag are Senni Beds of
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...
Old Red Sandstone
The Old Red Sandstone is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the northeastern seaboard of North America. It also exte ...
, topped with
Brownstones
Brownstone is a brown Triassic–Jurassic sandstone that was historically a popular building material. The term is also used in the United States and Canada to refer to a townhouse clad in this or any other aesthetically similar material.
Type ...
.
The ledges of the main crag to the south have been a favoured nesting site for
peregrine falcons
The peregrine falcon (''Falco peregrinus''), also known as the peregrine, and historically as the duck hawk in North America, is a cosmopolitan bird of prey (raptor) in the family Falconidae. A large, crow-sized falcon, it has a blue-grey back, ...
.
References
External links
www.geograph.co.uk : photos of Fan Fawr and surrounding area
Fforest Fawr
Mountains and hills of Powys
Hewitts of Wales
Nuttalls
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