Hay Bluff (

Welsh Welsh may refer to: Related to Wales * Welsh, referring or related to Wales * Welsh language, a Brittonic Celtic language spoken in Wales * Welsh people People * Welsh (surname) * Sometimes used as a synonym for the ancient Britons (Celtic peop ...

: ''Penybegwn'') is a prominent hill at the northern tip of the Black Mountains, an extensive upland massif which straddles the border between south-east

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

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

. The mountain sits at the point where the main northeast-facing

escarpment An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. The terms ''scarp'' and ''scarp face'' are often used interchangeably with ''escar ...

of the Black Mountains meets the northwest facing escarpment, the next peak to the west being

Twmpa Twmpa or Lord Hereford's Knob is a mountain in south-east Wales, forming a part of the great northwest scarp of the Black Mountains. It lies 1.86 miles (3 km) west of the border with England, and around 4.34 miles (7 km) south of Ha ...

. The flat summit of Hay Bluff which is marked by a

triangulation pillar 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 ...

at a height of overlooks the middle

Wye Valley The Wye Valley Area of Outstanding Natural Beauty (AONB; cy, Dyffryn Gwy) is an internationally important protected landscape straddling the border between England and Wales. The River Wye ( cy, Afon Gwy) is the fourth-longest river in th ...

and the

book town A book town is a town or village with many used book or antiquarian bookstores. These stores, as well as literary festivals, attract bibliophile tourists. Some book towns are members of the International Organisation of Book Towns. List of boo ...

Hay-on-Wye Hay-on-Wye ( cy, Y Gelli Gandryll), simply known locally as "Hay" ( cy, Y Gelli), is a market town and community in Powys, Wales; it was historically in the county of Brecknockshire. With over twenty bookshops, it is often described as "the t ...

. The hill is largely within the Welsh county of

Powys Powys (; ) is a Local government in Wales#Principal areas, county and Preserved counties of Wales, preserved county in Wales. It is named after the Kingdom of Powys which was a Welsh succession of states, successor state, petty kingdom and princi ...

though parts of its eastern flanks lie within the English county of

Herefordshire Herefordshire () is a county in the West Midlands of England, governed by Herefordshire Council. It is bordered by Shropshire to the north, Worcestershire to the east, Gloucestershire to the south-east, and the Welsh counties of Monmouthshire ...

Geology

The base and indeed greater part of the hill is formed from

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 of the St Maughans Formation whilst the upper part is formed from the

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

s and mudstones of the Senni Formation (formerly known as the 'Senni Beds'), both of which are assigned to the

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 ...

laid down during the

Devonian period 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, wh ...

. A number of small quarries have been worked on its slopes in the past, not least for the Ffynnon Limestone, a

calcrete Caliche () is a sedimentary rock, a hardened natural cement of calcium carbonate that binds other materials—such as gravel, sand, clay, and silt. It occurs worldwide, in aridisol and mollisol soil orders—generally in arid or semiarid regions, ...

which crops out along the northeastern and northwestern flanks of the hill at the base of the Senni Formation.

Access

The Offa's Dyke national trail makes a steep ascent of the hill's northern slopes and then heads south eastwards along the broad ridge of the Black Mountain and the

Hatterrall Ridge The Hatterrall Ridge (sometimes spelled Hatterall) is a ridge in the Black Mountains forming the border between Powys and Monmouthshire in Wales and Herefordshire in England. The ridge is about long, and is followed by the Offa's Dyke Path. O ...

. A more gentle path to the summit follows the crest of the northwest-facing scarp, known as Ffynnon y Parc, from the road summit about 1 mile / 1.7 km to the southwest at

Gospel Pass The Gospel Pass (Welsh: ''Bwlch yr Efengyl'') is the highest road pass in Wales. It is at the head of the Vale of Ewyas in the Black Mountains of southeast Wales. Starting from Hay-on-Wye the narrow mountain road climbs steeply to a height of ...

. There is also a clear, but unpaved path which passes along the edge of the escarpment to the east with good views over the countryside towards

. It leads to 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 nomenclature varies regionally: they a ...

at the Black Hill (Herefordshire), and continues on to the south-east dropping down the stony knife-edge ridge towards Longtown. There is a small car park where the ridge drops into the Olchon valley, about 2 miles north of Longtown itself. The entire hill is designated as open country thus providing walkers with the

freedom to roam The freedom to roam, or "everyman's right", is the general public's right to access certain public or privately owned land, lakes, and rivers for recreation and exercise. The right is sometimes called the right of public access to the wilderness ...

at will.Ordnance Survey 1:25,000 scale Explorer map sheet OL13 ''Brecon Beacons National Park; eastern area''

References

Black Mountains, Wales Mountains and hills of Powys Hills of Herefordshire {{Powys-geo-stub