Twmpa or Lord Hereford's Knob is a mountain in 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 ...

, 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

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 to ...

. To the northeast lies the

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 ...

through which runs a minor road between Hay and the Llanthony Valley. A ridge known as Darren Lwyd tapers away for about to the southeast of the summit.

Geology

In common with neighbouring hills, Twmpa is composed of alternate layers of

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) ...

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 (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...

dating from the

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 ...

period and ascribed to the Lower

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 ...

. Its lower slopes are formed from the mudstone-dominated St Maughans Formation whilst the upper part of the hill is composed of sandstone-dominated Senni Formation rocks. At the junction between the two is a prominent

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, ...

known as the Ffynnon Limestone. Numerous landslips have occurred within the St Maughans Formation around the flanks of the hill.

Access

The entire hill is classed 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 CRoW Act and is therefore available for walkers to roam freely across. It is almost encircled by public bridleways and

restricted byway A byway in the United Kingdom is a track, often rural, which is too minor to be called a road. These routes are often unsurfaced, typically having the appearance of ' green lanes'. Despite this, it is legal (but may not be physically possible) to ...

s. The most well-used track is that running west from Gospel Pass (where car parking is available), over its summit and then southwest towards

Rhos Dirion Rhos Dirion is a top of Waun Fach in the Black Mountains in south-eastern Wales. It is the highest point on the Rhos Dirion - Chwarel y Fan ridge. The summit is marked by a trig point A triangulation station, also known as a trigonometrical ...

. A further track runs the length of the ridge southeastwards to the hamlet of

Capel-y-ffin Capel-y-ffin ('' en, Chapel of the Boundary'') is a hamlet near the English-Welsh border, a couple of miles north of Llanthony in Powys, Wales. It lies within the Black Mountains and within the Brecon Beacons National Park. The nearest town is H ...

In popular culture

Lord Hereford's Knob was the subject of a satirical

folk rock Folk rock is a hybrid music genre that combines the elements of folk and rock music, which arose in the United States, Canada, and the United Kingdom in the mid-1960s. In the U.S., folk rock emerged from the folk music revival. Performers suc ...

song of the same name by

post-punk Post-punk (originally called new musick) is a broad genre of punk music that emerged in the late 1970s as musicians departed from punk's traditional elements and raw simplicity, instead adopting a variety of avant-garde sensibilities and non-roc ...

band Half Man Half Biscuit. It features on their 2008 album '' CSI:Ambleside''. The mountain also appears in the poem ''Wales Visitation'' by

Allen Ginsberg Irwin Allen Ginsberg (; June 3, 1926 – April 5, 1997) was an American poet and writer. As a student at Columbia University in the 1940s, he began friendships with William S. Burroughs and Jack Kerouac, forming the core of the Beat Gener ...

, written under the influence of LSD during a visit to the cottage of his publisher

Tom Maschler Thomas Michael Maschler (16 August 193315 October 2020) was a British publisher and writer. He was noted for instituting the Booker Prize for British, Irish and Commonwealth literature in 1969. He was involved in publishing the works of many no ...

in the summer of 1967.Roberts, Andy. (15 September 2016
No Imperfection in the Budded Mountain: Allen Ginsberg and the writing of Wales VisitationPsychedelic Press UK
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References

External links

Photos of Twmpa on geograph.org.uk
Hewitts of Wales Nuttalls Mountains and hills of Powys Black Mountains, Wales {{Powys-geo-stub