The Black Mountains are a group of hills spread across parts of Powys and Monmouthshire in southeast Wales, and extending across the England–Wales border into Herefordshire. They are the easternmost of the four ranges of hills that comprise the Brecon Beacons National Park, and are frequently confused with the westernmost, which is known as the Black Mountain. The Black Mountains may be roughly defined as those hills contained within a triangle defined by the towns of Abergavenny in the southeast, Hay-on-Wye in the north and the village of Llangors in the west. Other gateway towns to the Black Mountains include Talgarth and Crickhowell. The range of hills is well known to walkers and ramblers for the ease of access and views from the many ridge trails, such as that on the Black Hill (Herefordshire) at the eastern edge of the massif. The range includes the highest public road in Wales at Gospel Pass, and the highest point in southern England at Black Mountain.
Craig Cerrig-gleisiad is a subsidiary summit of Fan Fawr in the Fforest Fawr section of the Brecon Beacons National Park, South Wales. It makes up half of the Craig Cerrig-gleisiad and Fan Frynych National Nature Reserve with its sister peak Fan Frynych.
Henrhyd Falls in the Brecon Beacons National Park, Wales, is the tallest waterfall in southern Wales with a drop of 90 feet (27 m). It lies on National Trust land, in the county of Powys. The nearest settlement to it is Coelbren, on the road between Glynneath and Abercraf. Though not in the core of the area, it is considered by many to constitute a part of Wales' celebrated Waterfall Country.
The geology of Wales is complex and varied; its study has been of considerable historical significance in the development of geology as a science. All geological periods from the Cryogenian to the Jurassic are represented at outcrop, whilst younger sedimentary rocks occur beneath the seas immediately off the Welsh coast. The effects of two mountain-building episodes have left their mark in the faulting and folding of much of the Palaeozoic rock sequence. Superficial deposits and landforms created during the present Quaternary period by water and ice are also plentiful and contribute to a remarkably diverse landscape of mountains, hills and coastal plains.
The Nant Llech is a minor river in Powys, Wales and which lies wholly within the Brecon Beacons National Park. The name means 'slab stream', presumably in reference to the sandstones across which it runs. Its headwater streams, the Nant Llech Pellaf and the Nant Llech Isaf join forces at Blaen Llech and then continue westwards as the Nant Llech for 3 km / 2 mi to a confluence with the River Tawe just east of the village of Abercraf.
Fan Nedd is a mountain in the Fforest Fawr area of the Brecon Beacons National Park in Wales. In common with the rest of the Fforest Fawr uplands it is within the county of Powys.
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.
Fan Bwlch Chwyth is a peak in the Fforest Fawr section of the Brecon Beacons National Park and within the county of Powys.
Fan Hir is a peak at the eastern end of the Black Mountain in the Brecon Beacons National Park in southern Wales. It is a subsidiary summit of Fan Brycheiniog. It falls within the county of Powys and is also a part of the traditional area of Fforest Fawr. Its Welsh name means "long peak", a fitting description, particularly if seen from the east when its steep eastern face is seen to advantage. It is about 2.5 miles or 4 km long and faces east. Its summit is 2490 feet above sea level. Fan Hir is separated from its higher neighbour to the north-west, Fan Brycheiniog by a col known as Bwlch Giedd, where a path rises from Llyn y Fan Fawr via a stone staircase.
Heol Senni is a hamlet in the valley of the Afon Senni just north of the Fforest Fawr section of the Brecon Beacons National Park. It lies within the community of Maescar in the county of Powys, Wales. The Welsh name means the 'road by Senni' and reflects its position near the crossing of the river by the minor road running from the A4067 to the A4215 road. This route was, and to some extent still is, an important link between Brecon and the upper Swansea Valley.
The Grwyne Fawr is a river in the Brecon Beacons National Park in south Wales. A section of it forms the administrative border between Powys and Monmouthshire and also of the historic counties of Brecon and Monmouth. The river and its major tributary the Grwyne Fechan flow into the River Usk at Glangrwyney.
Mynydd Llangynidr is a mountain in the Brecon Beacons National Park largely in the county of Powys, south Wales. Its southern slopes extend into the northernmost parts of the county borough of Blaenau Gwent. It is named from the village of Llangynidr which sits in the valley of the River Usk to the north of it. It is essentially an undulating plateau rising in the west to a height of 557m at Garn Fawr at OS grid ref SO 123151. A secondary high point is achieved at a point marked by a trig point at SO 147159. To the north the hill overlooks the valleys of Dyffryn Crawnon and Cwm Claisfer, themselves tributary valleys of the Usk. The shallow upper valley of the Ebbw River reaches into the plateau in the southeast whilst the upper reaches of the Sirhowy Valley and its tributary the Nant Trefil define its western margins. A further tributary, the Nant Milgatw, reaches in from the south whilst the sharp edge of Rassau Industrial Estate also defines a part of its southern margin. Passing east across the B4560, the hill merges with Mynydd Llangatwg which has a similar character.
Allt yr Esgair is a hill in the Brecon Beacons National Park in Powys, Wales. It is commonly referred to locally as simply 'The Allt'. The Welsh name signifies 'wooded slope of the ridge'. It takes the form of a northwest-southeast aligned ridge which rises to a height of 393m and which overlooks the valley of the River Usk to the west and south. To the northeast are panoramic views across Llangorse Lake to the Black Mountains There is a viewfinder on the summit erected as a monument to Eirene Lloyd White, Baroness White of Rhymney. It is a Marilyn with a prominence of 199 metres.
Cefn Cul is a hill in the Fforest Fawr sector of the Brecon Beacons National Park in Powys, southern Wales. It is a broad north-northeast to south-southwest aligned ridge whose summit reaches a height of 562 m above sea level. The hill is bounded to the west by the upper valley of the River Tawe though which the old Trecastle road runs whilst to the east is the pass of Bwlch Bryn-rhudd over which the A4067 road runs from the Crai valley south to that of the Tawe.
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 that was, until the local government re-organisation of 1974, within the historic county of Brecknockshire.
The geology of Monmouthshire in southeast Wales largely consists of a thick series of sedimentary rocks of different types originating in the Silurian, Devonian, Carboniferous, Triassic and Jurassic periods.
Hay Bluff is a prominent hill at the northern tip of the Black Mountains, an extensive upland massif which straddles the border between south-east Wales and England. The mountain sits at the point where the main northeast-facing escarpment of the Black Mountains meets the northwest facing escarpment, the next peak to the west being Twmpa. The flat summit of Hay Bluff which is marked by a triangulation pillar at a height of 677 metres (2,221 ft) overlooks the middle Wye Valley and the book town of Hay-on-Wye.
Land Grove Quarry, Mitcheldean is a 3.8-hectare (9.4-acre) geological Site of Special Scientific Interest in Gloucestershire, England, notified in 1974. The site is listed in the 'Forest of Dean Local Plan Review' as a Key Wildlife Site (KWS).
Buckland Hill is a low hill in the Brecon Beacons National Park in the county of Powys in Wales. Sitting transversely across the Usk valley between the river and the village of Bwlch, it provides excellent panoramic views down the valley and across to the Black Mountains. The summit at 316m above sea level is marked by an OS trig point though this is now within a dense conifer plantation and so no longer affords any outward views. Buckland Hall sits at the foot of the hill's afforested northwestern side.
This article describes the geology of the Brecon Beacons National Park in mid/south Wales. The area gained national park status in 1957 with the designated area of 1,344 km2 (519 sq mi) including mountain massifs to both the east and west of the Brecon Beacons proper. The geology of the national park consists of a thick succession of sedimentary rocks laid down from the late Ordovician through the Silurian and Devonian to the late Carboniferous period. The rock sequence most closely associated with the park is the Old Red Sandstone from which most of its mountains are formed. The older parts of the succession, in the northwest, were folded and faulted during the Caledonian orogeny. Further faulting and folding, particularly in the south of the park is associated with the Variscan orogeny.
