Cefn yr Ystrad is a

mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher t ...

in the

Brecon Beacons The Brecon Beacons (; ) are a mountain range in Wales. The range includes South Wales's highest mountain, Pen y Fan (), its twin summit Corn Du (), and Craig Gwaun Taf (), which are the three highest peaks in the range. The Brecon Beacons ha ...

National Park A national park is a nature park designated for conservation (ethic), conservation purposes because of unparalleled national natural, historic, or cultural significance. It is an area of natural, semi-natural, or developed land that is protecte ...

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 ...

. It is an outlier of the Central Beacons group. The broad northeast - southwest aligned ridge reaches an elevation of . One of the southernmost peaks in the Brecon Beacons, it rises to the east of

Pontsticill Reservoir Pontsticill Reservoir () or Taf Fechan Reservoir is a large reservoir on the Taf Fechan lying partly in the county of Powys and partly within the county borough of Merthyr Tydfil in south Wales. It lies within the Brecon Beacons National Park a ...

. The summit area is a great stretch of wild

moorland Moorland or moor is a type of Habitat (ecology), habitat found in upland (geology), upland areas in temperate grasslands, savannas, and shrublands and the biomes of montane grasslands and shrublands, characterised by low-growing vegetation on So ...

, with the highest point marked by 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 station is usually set up by a map ...

Geology

The hill is formed from successive layers of Carboniferous Limestone and the overlying

Twrch Sandstone The Marros Group is the name given to a suite of rocks of Namurian age laid down during the Carboniferous period (geology), Period in South Wales. These rocks were formerly known as the Millstone Grit, Millstone Grit Series but are now distinguish ...

(formerly known as the ''Basal Grit'' of the

Millstone Grit Millstone Grit is any of a number of coarse-grained sandstones of Carboniferous age which occur in the British Isles. The name derives from its use in earlier times as a source of millstones for use principally in watermills. Geologists refer to ...

). The

rock strata In geology and related fields, a stratum (: strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ...

generally dip to the south but are locally disrupted by foundering of the

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 ...

as the underlying

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

has dissolved away. There are extensive ice-smoothed pavements of the latter and loose rock abounds. The crest and southern slopes of the hill are home to dozens of shakeholes, some of which reach considerable proportions.

Archaeology

The hill is scattered with

archaeological site An archaeological site is a place (or group of physical sites) in which evidence of past activity is preserved (either prehistoric or recorded history, historic or contemporary), and which has been, or may be, investigated using the discipline ...

s from the

Bronze Age The Bronze Age () was a historical period characterised principally by the use of bronze tools and the development of complex urban societies, as well as the adoption of writing in some areas. The Bronze Age is the middle principal period of ...

through to the industrial period. Pre-eminent amongst these are Garn Felen and Carn-y-Bugail; the latter, which translates as ‘cairn of the shepherd’, is a 15m diameter burial cairn southeast of the summit. It stands at 3m high but has been partly disturbed. Numerous nineteenth century boundary stones can traced across the hill bearing the engraved letters ‘D of B, TM’ on the one side and ‘GH’ on the other, marking the boundary between the estates of the

Duke of Beaufort Duke of Beaufort ( ) is a title in the Peerage of England. It was created by Charles II in 1682 for Henry Somerset, 3rd Marquess of Worcester, a descendant of Charles Somerset, 1st Earl of Worcester, legitimised son of Henry Beaufort, 3rd D ...

, Tretower Manor and of the Gwynne Holford’s who were established at Buckland Hall near Bwlch A number of more recent structures and tracks are associated with the now-abandoned limestone quarries of Cwar Blaen-dyffryn, Cwar y Hendre and Cwar yr Ystrad on the northern and northwestern flanks of the hill.

Access

The hill lies entirely within open country and so access on foot is freely available. A bridleway running northeast from

Pontsticill Pontsticill is a village within the County Borough of Merthyr Tydfil in South Wales. It lies within the valley of the Taf Fechan on the southern edge of the Brecon Beacons National Park. The village lies within the community of Vaynor in an area ...

skirts the northwestern edge of the hill bound for Dyffryn Crawnon and the Usk Valley.Ordnance Survey 1:25K Explorer map sheet OL12 & OL13 ''Brecon Beacons National Park: western & eastern areas''

References

External links

www.geograph.co.uk : photos of Cefn yr Ystrad and surrounding area
{{coord, 51.81443, -3.32730, type:landmark_region:GB_source:enwiki-osgb36(SO086137), display=title Brecon Beacons Mountains and hills of Powys Marilyns of Wales Hewitts of Wales Nuttalls