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Nedd Fechan
The Nedd Fechan is a river almost wholly within the county of Powys, Wales. It rises on the eastern slopes of Fan Gyhirych in the Fforest Fawr section of the Brecon Beacons National Park and flows south for to join with the Afon Mellte at Pontneddfechan, their combined waters continuing as the River Neath ( Welsh Afon Nedd) to the sea near Swansea. The only significant tributary of the Nedd Fechan is the Afon Pyrddin which joins it at Pwll Du ar Byrddin ('the black pool of the Pyrddin'). Downstream of this confluence it forms the boundary between Powys to its east and Neath Port Talbot to its west. Geology The headwaters of the river run over Old Red Sandstone as far as Blaen-nedd-isaf where they encounter the Carboniferous Limestone outcrop. The river then continues through a wooded gorge for the remainder of its course. The section downstream of Pont Rhyd-y-cnau is cut in sandstones and mudstones of the Millstone Grit series. The section between Pont Melin-fach and the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Powys
Powys ( , ) is a Principal areas of Wales, county and Preserved counties of Wales, preserved county in Wales. It borders Gwynedd, Denbighshire, and Wrexham County Borough, Wrexham to the north; the English Ceremonial counties of England, ceremonial counties of Shropshire and Herefordshire to the east; Monmouthshire, Blaenau Gwent, Merthyr Tydfil County Borough, Merthyr Tydfil, Caerphilly County Borough, Caerphilly, Rhondda Cynon Taf, and Neath Port Talbot to the south; and Carmarthenshire and Ceredigion to the west. The largest settlement is Newtown, Powys, Newtown, and the administrative centre is Llandrindod Wells. Powys is the largest and most sparsely populated county in Wales, having an area of and a population of in . While largely rural, its towns include Welshpool in the north-east, Newtown in the north-centre, Llandrindod Wells in the south-centre, Brecon in the south, Ystradgynlais in the far south-west, and Machynlleth in the far west. The Welsh language can be spok ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Old Red Sandstone
Old Red Sandstone, abbreviated ORS, 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 eastern seaboard of North America. It also extends northwards into Greenland and Svalbard. These areas were a part of the paleocontinent of Euramerica (Laurussia). In Britain it is a lithostratigraphic unit (a sequence of rock strata) to which stratigraphers accord supergroup status and which is of considerable importance to early paleontology. The presence of ''Old'' in the name is to distinguish the sequence from the younger New Red Sandstone which also occurs widely throughout Britain. Sedimentology The Old Red Sandstone describes a group of sedimentary rocks deposited in a variety of environments in the late Silurian, through the Devonian and into the earliest part of the Carboniferous. The body of rock, or facies, is dominated by terrigenous deposits and co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rivers Of The Brecon Beacons National Park
A river is a natural stream of fresh water that flows on land or inside caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it runs out of water, or only flow during certain seasons. Rivers are regulated by the water cycle, the processes by which water moves around the Earth. Water first enters rivers through precipitation, whether from rainfall, the runoff of water down a slope, the melting of glaciers or snow, or seepage from aquifers beneath the surface of the Earth. Rivers flow in channeled watercourses and merge in confluences to form drainage basins, or catchments, areas where surface water eventually flows to a common outlet. Rivers have a great effect on the landscape around them. They may regularly overflow their banks and flood the surrounding area, spreading nutrients to the surrounding area. Sediment or alluvium carried by rivers shapes the landscape aro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waggonway
A wagonway (or waggonway; also known as a horse-drawn railway, or horse-drawn railroad) was a method of railway transportation that preceded the steam locomotive and used horses to haul wagons. The terms plateway and tramway were also used. The advantage of wagonways was that far bigger loads could be transported with the same power compared to horse haulage along roads. Ancient systems The earliest evidence is of the long ''Diolkos'' paved trackway, which transported boats across the Isthmus of Corinth in Greece from around 600 BC. Wheeled vehicles pulled by men and animals ran in grooves in limestone, which provided the track element, preventing the wagons from leaving the intended route. The Diolkos was in use for over 650 years, until at least the 1st century AD. Paved trackways were later built in Roman Egypt. Wooden rails Such an operation was illustrated in Germany in 1556 by Georgius Agricola (image left) in his work De re metallica. This line used "Hund" carts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adit
An adit (from Latin ''aditus'', entrance) or stulm is a horizontal or nearly horizontal passage to an underground mine. Miners can use adits for access, drainage, ventilation, and extracting minerals at the lowest convenient level. Adits are also used to explore for mineral veins. Although most strongly associated with mining, the term ''adit'' is sometimes also used in the context of underground excavation for non-mining purposes; for example, to refer to smaller underground passageways excavated for underground metro systems, to provide pedestrian access to stations (pedestrian adits), and for access required during construction (construction adits). Construction Adits are driven into the side of a hill or mountain, and are often used when an ore body is located inside the mountain but above the adjacent valley floor or coastal plain. In cases where the mineral vein outcrops at the surface, the adit may follow the lode or vein until it is worked out, in which case the ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bryophyte
Bryophytes () are a group of embryophyte, land plants (embryophytes), sometimes treated as a taxonomic Division (taxonomy), division referred to as Bryophyta ''Sensu#Common qualifiers, sensu lato'', that contains three groups of non-vascular plant, non-vascular land plants: the Marchantiophyta, liverworts, hornworts, and mosses. In the Sensu#Common qualifiers, strict sense, the division Bryophyta consists of the mosses only. Bryophytes are characteristically limited in size and prefer moist habitats although some species can survive in drier environments. The bryophytes consist of about 20,000 plant species. Bryophytes produce enclosed reproductive structures (gametangia and sporangia), but they do not produce flowers or seeds. They reproduce sexually by spores and asexually by fragmentation or the production of Gemma (botany), gemmae. Though bryophytes were considered a paraphyletic group in recent years, almost all of the most recent phylogenetics, phylogenetic evidence support ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Special Area Of Conservation
A special area of conservation (SAC) is defined in the European Union's Habitats Directive (92/43/EEC), also known as the ''Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora''. They are to protect the 220 habitats and approximately 1,000 species listed in annex I and II of the directive which are considered to be of European interest following criteria given in the directive. They must be chosen from the Site of Community Importance, sites of Community importance by the member states and designated SAC by an act assuring the conservation measures of the natural habitat. SACs complement special protection areas and together form a network of protected sites across the European Union called Natura 2000. This, in turn, is part of the Emerald network of Area of Special Conservation Interest, Areas of Special Conservation Interest (ASCIs) under the Convention on the conservation of European wildlife and natural habitats, Berne Convention. Assessment methodol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Site Of Special Scientific Interest
A Site of Special Scientific Interest (SSSI) in Great Britain, or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland, is a conservation designation denoting a protected area in the United Kingdom and Isle of Man. SSSI/ASSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in the United Kingdom are based upon them, including national nature reserve (United Kingdom), national nature reserves, Ramsar Convention, Ramsar sites, Special Protection Areas, and Special Area of Conservation, Special Areas of Conservation. The acronym "SSSI" is often pronounced "triple-S I". Selection and conservation Sites notified for their Biology, biological interest are known as Biological SSSIs (or ASSIs), and those notified for geological or Physical geography, physiographic interest are Geological SSSIs (or ASSIs). Sites may be divided into management units, with some a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fault (geology)
In geology, a fault is a Fracture (geology), planar fracture or discontinuity in a volume of Rock (geology), rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust (geology), crust result from the action of Plate tectonics, plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction, subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the Plane (geometry), plane that represents the fracture surface of a fault. A ''fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geological maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 whole suite of rocks that encompass the individual limestone beds and the intervening mudstones as the Millstone Grit Group. The term Millstone Grit Series was formerly used to refer to the rocks now included within the Millstone Grit Group together with the underlying Edale Shale Group. The term gritstone describes any sandstone composed of coarse angular grains, and specifically refers to such sandstones within the Pennines and neighbouring areas of Northern England. Geographical occurrence Rocks assigned to the Millstone Grit Group occur over a wide area of Northern England, where they are a hugely important landscape-forming element of the rock succession. They also occur in parts of northeast Wales and northwest Ireland. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neath Port Talbot
Neath Port Talbot () is a Principal areas of Wales, county borough in the South West Wales, south-west of Wales. Its principal towns are Neath, Port Talbot, Briton Ferry and Pontardawe. The county borough borders Bridgend County Borough and Rhondda Cynon Taf to the east, Powys and Carmarthenshire to the north; and Swansea to the west. Neath Port Talbot is the eighth-most List of Welsh principal areas by population, populous local authority area in Wales and the third most populous county borough. The population at the United Kingdom Census 2011, 2011 census was 139,812. The population in the coastal areas is mainly English-speaking, whereas in the valleys in the north of the borough there are many who are Welsh-speaking. Geography The local authority area stretches from the coast to the border of the Brecon Beacons National Park. The majority of the land is upland or semi-upland and 43% is covered by forestry with major conifer plantations in upland areas. Most of the lower-lyi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
