Pen Cerrig-Calch
Encyclopedia
Pen Cerrig-calch is a subsidiary summit
of Waun Fach
in the Black Mountains
in the Brecon Beacons National Park in southern Powys
, Wales
. Its summit, at a height of 701m (2,300 ft), is marked by a trig point
. The peak sits high above the River Usk
valley as it narrows above the small town of Crickhowell
.The views from here are wide ranging and extend as far as the Beacons themselves to the west. A ridge runs off to the northwest and the shoulder of Pen Gloch-y-pibwr then turns north to the secondary top of Pen Allt-mawr
whose peak at 719m is also crowned by a trig point.
laid down during the Devonian period but it is unusual in having a band of Carboniferous Limestone
outcropping around the summit and giving rise to a few shakeholes. A classic example of an inlier
, the name of the hill reflects this situation; it means 'top of the limestone rock' in Welsh
. The actual summit itself is formed from pebbly sandstone of the Marros Group
(formerly the Millstone Grit
Series), which also dates from the Carboniferous period.
The rounded southwestern shoulder of the hill ends abruptly at a cliff by the name of Darren (Welsh
'edge') which was formed by a sizeable landslip which most probably occurred in the early post-glacial period. A large area of hummocky ground abounding with boulders of Old Red Sandstone lies across the slopes below Darren.
, a presumed Iron Age
hillfort sitting atop a tilted mass of gritstone on the hill's southeastern spur and otherwise known as Table Mountain. However there are also ancient cairns on each of the main tops. Small disused quarries once worked for the Old Red Sandstone are scattered across the hill's lower slopes.
Valley and from the valley of the Grwyne Fechan to the east. The Beacons Way skirts the hill's southern and western slopes. The most popular route to the summit is the approach up the southeastern spur from Crug Hywel
(Table Mountain).
Spur (mountain)
A spur is a subsidiary summit of a hill or mountain. By definition, spurs have low topographic prominence, as they are lower than their parent summit and are closely connected to them on the same ridgeline...
of Waun Fach
Waun Fach
Waun Fach is the highest mountain in the Black Mountains in south-eastern Wales. It is one of the three Marilyns over 600m that make up the range, the others being Black Mountain and Mynydd Troed. To the north Rhos Fawr and the Radnor Forest can be seen.It is situated at the head of the Grwyne...
in the Black Mountains
Black Mountains, Wales
The Black Mountains are a group of hills spread across parts of Powys and Monmouthshire in southeast Wales, and extending across the national border into Herefordshire, England. They are the easternmost of the four ranges of hills that comprise the Brecon Beacons National Park, and are frequently...
in the Brecon Beacons National Park in southern Powys
Powys
Powys is a local-government county and preserved county in Wales.-Geography:Powys covers the historic counties of Montgomeryshire and Radnorshire, most of Brecknockshire , and a small part of Denbighshire — an area of 5,179 km², making it the largest county in Wales by land area.It is...
, Wales
Wales
Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...
. Its summit, at a height of 701m (2,300 ft), is marked by a trig point
Trig point
A triangulation station, also known as a triangulation pillar, trigonometrical station, trigonometrical point, trig station, trig beacon or trig point, and sometimes informally as a trig, is a fixed surveying station, used in geodetic surveying and other surveying projects in its vicinity...
. The peak sits high above the River Usk
River Usk
The River Usk rises on the northern slopes of the Black Mountain of mid-Wales, in the easternmost part of the Brecon Beacons National Park. Initially it flows north into Usk Reservoir, then east by Sennybridge to Brecon before turning southeast to flow by Talybont-on-Usk, Crickhowell and...
valley as it narrows above the small town of Crickhowell
Crickhowell
Crickhowell is a small town in Powys, Mid Wales.-Location:The name Crickhowell is taken from that of the nearby Iron Age hill fort of Crug Hywel above the town, the Welsh language name being anglicised by map-makers and local English-speaking people...
.The views from here are wide ranging and extend as far as the Beacons themselves to the west. A ridge runs off to the northwest and the shoulder of Pen Gloch-y-pibwr then turns north to the secondary top of Pen Allt-mawr
Pen Allt-mawr
Pen Allt-mawr is subsidiary summit of Waun Fach and the third highest peak in the Black Mountains in south-eastern Wales. It lies near the end of the westernmost of Waun Fach's south ridges. It is a very recognisable and prominent peak of the Black Mountains.It summit is stony and has a large...
whose peak at 719m is also crowned by a trig point.
Geology
Like all of the hills in the Black Mountains, Pen Cerrig-calch is formed from mudstones and sandstones of the Old Red SandstoneOld Red Sandstone
The Old Red Sandstone is a British rock formation of considerable importance to early paleontology. For convenience the short version of the term, 'ORS' is often used in literature on the subject.-Sedimentology:...
laid down during the Devonian period but it is unusual in having a band of Carboniferous Limestone
Carboniferous limestone
Carboniferous Limestone is a term used to describe a variety of different types of limestone occurring widely across Great Britain and Ireland which were deposited during the Dinantian epoch of the Carboniferous period. They were formed between 363 and 325 million years ago...
outcropping around the summit and giving rise to a few shakeholes. A classic example of an inlier
Inliers and outliers (geology)
An inlier is an area of older rocks surrounded by younger rocks. Inliers are typically formed by the erosion of overlying younger rocks to reveal a limited exposure of the older underlying rocks. Faulting or folding may also contribute to the observed outcrop pattern...
, the name of the hill reflects this situation; it means 'top of the limestone rock' in Welsh
Welsh language
Welsh is a member of the Brythonic branch of the Celtic languages spoken natively in Wales, by some along the Welsh border in England, and in Y Wladfa...
. The actual summit itself is formed from pebbly sandstone of the Marros Group
Marros Group
The Marros Group is the name given to a suite of rocks of Namurian age laid down during the Carboniferous period in South Wales. These rocks were formerly known as the Millstone Grit Series but are now distinguished from the similar but geographically separate rock sequences of the Pennines and...
(formerly the Millstone Grit
Millstone Grit
Millstone Grit is the name given to any of a number of coarse-grained sandstones of Carboniferous age which occur in the Northern England. The name derives from its use in earlier times as a source of millstones for use principally in watermills...
Series), which also dates from the Carboniferous period.
The rounded southwestern shoulder of the hill ends abruptly at a cliff by the name of Darren (Welsh
Welsh language
Welsh is a member of the Brythonic branch of the Celtic languages spoken natively in Wales, by some along the Welsh border in England, and in Y Wladfa...
'edge') which was formed by a sizeable landslip which most probably occurred in the early post-glacial period. A large area of hummocky ground abounding with boulders of Old Red Sandstone lies across the slopes below Darren.
Archaeology
The most celebrated feature of the hill is the fortification of Crug HywelCrug Hywel
Crug Hywel is a flat-topped hill at the southern edge of the Black Mountains in south-east Wales.It rises to 451 m above sea level, from the southern flank of Pen Cerrig-calch , and overlooks the town of Crickhowell , to which it gives its name.The summit of the hill is entirely taken up by...
, a presumed Iron Age
Iron Age
The Iron Age is the archaeological period generally occurring after the Bronze Age, marked by the prevalent use of iron. The early period of the age is characterized by the widespread use of iron or steel. The adoption of such material coincided with other changes in society, including differing...
hillfort sitting atop a tilted mass of gritstone on the hill's southeastern spur and otherwise known as Table Mountain. However there are also ancient cairns on each of the main tops. Small disused quarries once worked for the Old Red Sandstone are scattered across the hill's lower slopes.
Access
The upper parts of the hill are mapped as open country so walkers can wander at will over it. Various footpaths approach the open access land from the UskUsk
Usk is a small town in Monmouthshire, Wales, situated 10 miles northeast of Newport.The River Usk flows through the town and is spanned by an ancient, arched stone bridge at the western entrance to the town. A castle above the town overlooks the ancient Anglo-Welsh border crossing - the river can...
Valley and from the valley of the Grwyne Fechan to the east. The Beacons Way skirts the hill's southern and western slopes. The most popular route to the summit is the approach up the southeastern spur from Crug Hywel
Crug Hywel
Crug Hywel is a flat-topped hill at the southern edge of the Black Mountains in south-east Wales.It rises to 451 m above sea level, from the southern flank of Pen Cerrig-calch , and overlooks the town of Crickhowell , to which it gives its name.The summit of the hill is entirely taken up by...
(Table Mountain).