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Drefach Group
The Drefach Group is an Ordovician lithostratigraphic group (a sequence of rock strata) in west Wales. The name is derived from the village of Drefach near Meidrim (a.k.a. Mydrim) in Carmarthenshire. The Group comprises the Mydrim Shales Formation, the Mydrim Limestone Formation, the Hendre Shales Formation, Asaphus Ash Formation and at its base, the underlying Felin-wen Formation. Outcrops The rocks are intermittently exposed in a belt of country running east from Fishguard Bay via Crymych then south towards Meidrim thence east via the north of Carmarthen along the Vale of Towy to Llandeilo.British Geological Survey 1:50,000 scale geological map (England & Wales) sheets 210, 211, 212, 228, 229 Lithology and stratigraphy The Group comprises in places more than a 400m thickness of mudstones (Mydrim Shales Formation), turbidite mudstones (Hendre Shales Formation), limestone (Mydrim Limestone Formation), tuffs and tuffite Tuffite is a tuff containing both pyroclastic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group (stratigraphy)
In geology, a group is a lithostratigraphic unit consisting of a series of related formations that have been classified together to form a group. Formations are the fundamental unit of stratigraphy. Groups may sometimes be combined into supergroups. Groups are useful for showing relationships between formations, and they are also useful for small-scale mapping or for studying the stratigraphy of large regions. Geologists exploring a new area have sometimes defined groups when they believe the strata within the groups can be divided into formations during subsequent investigations of the area. It is possible for only some of the strata making up a group to be divided into formations. An example of a group is the Glen Canyon Group, which includes (in ascending order) the Wingate Sandstone, the Moenave Formation, the Kayenta Formation, and the Navajo Sandstone. Each of the formations can be distinguished from its neighbor by its lithology, but all were deposited in the same vast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carmarthenshire
Carmarthenshire ( cy, Sir Gaerfyrddin; or informally ') is a county in the south-west of Wales. The three largest towns are Llanelli, Carmarthen and Ammanford. Carmarthen is the county town and administrative centre. The county is known as the "Garden of Wales" and is also home to the National Botanic Garden of Wales. Carmarthenshire has been inhabited since prehistoric times. The county town was founded by the Romans, and the region was part of the Kingdom of Deheubarth in the High Middle Ages. After invasion by the Normans in the 12th and 13th centuries it was subjugated, along with other parts of Wales, by Edward I of England. There was further unrest in the early 15th century, when the Welsh rebelled under Owain Glyndŵr, and during the English Civil War. Carmarthenshire is mainly an agricultural county, apart from the southeastern part which was once heavily industrialised with coal mining, steel-making and tin-plating. In the north of the county, the woollen industr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician System Of Europe
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cambrian Peri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caradoc
Caradoc Vreichvras (; Modern cy, Caradog Freichfras, ) was a semi-legendary ancestor to the kings of Gwent. He may have lived during the 5th or 6th century. He is remembered in the Matter of Britain as a Knight of the Round Table, under the names King Carados and Carados Briefbras (French for "Carados Shortarm"). Identification and historicity Though the name "Caradoc" and its various forms were by no means uncommon during the Middle Ages, it is probable some of the Caradocs referred to in Welsh genealogies and hagiographies such the ''Life of St. Tatheus'' are the same person. Due to the name's prevalence considerable confusion exists about Caradoc's identity, both historical and literary. He may have become confused with the British hero Caratacus (the Latin form of Caradoc), Cerdic of Wessex and any number of British history's later Caradocs. His parentage varies from text to text; he is called the son of Llŷr Marini (possibly implying Llŷr) several times in the '' Mabin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Llanvirn
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same Rock (geology), rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed Stratum, strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Union of Geological Sciences, International Geological Congress. Life continued to f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Welsh Basin
The Welsh Basin was a northeast-southwest aligned back-arc depositional basin during the Cambrian, Ordovician and Silurian periods during which a considerable thickness of marine sediments was laid down in the area. To the southeast lay the Midland Platform (a part of the micro-continent of Avalonia) and to the northwest, within the Iapetus Ocean, through what is now Ireland and the Lake District, was an island arc; a northeast-southwest aligned Irish Sea landmass which was associated with volcanic activity. Examination of the sediments and associated fossils allows the deeper centre of the basin to be distinguished from shallower 'platform' areas along its southeastern margins. From the middle Silurian onwards, collision of Avalonia with the more northerly continent of Laurentia occurred giving rise to the Caledonian Orogeny. The inversion of the basin occurred at that time i.e. its uplift and deformation. The southeastern limit of the Welsh Basin can be defined as the Welsh Bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuffite
Tuffite is a tuff containing both pyroclastic and detrital materials, but predominantly pyroclasts. According to IUGS definition tuffite contains 75 to 25% volcanic (epiclastic) material. There are several classifications that define tuffite. The classification present in the IUGS recommendation are based on the definition established by Schmid (1981). Shvetsov defined tuffites as rocks containing 50 to 90% of the volcanic fragments. Tuffite should therefore contain more than half of volcanic material. If rock contains more than 75 to 90% of pyroclastic material it is referred to as tuff. Some other, mostly older sources state that tuffite may contain 10 to 50% volcanic material. (in Czech) The adjective ''tuffitic'' is used for sediments containing less than 25% volcanic fragments. A tuffite consists of angular and/or rounded fragments of effusive rocks and their minerals, also may contain volcanic ash, pumice and clay minerals. Nonvolcanic material may consist of terrig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Llandeilo
Llandeilo () is a town and community in Carmarthenshire, Wales, situated at the crossing of the River Towy by the A483 on a 19th-century stone bridge. Its population was 1,795 at the 2011 Census. It is adjacent to the westernmost point of the Brecon Beacons National Park. The town is served by Llandeilo railway station on the Heart of Wales Line. In 2021, ''The Sunday Times'' called the town one of the top six places to live in Wales. The newspaper praised the town as a ‘sophisticated shopping destination and a great showcase for local arts and crafts’. Early history Roman soldiers were active in the area around Llandeilo around AD74, as evidenced by the foundations of two castra discovered on the grounds of the Dinefwr estate. The fortifications measured 3.85 hectares and 1.54 hectares, respectively. Roman roads linked Llandeilo with Llandovery and Carmarthen. A small civil settlement developed outside the gates of the fort and may have continued in use as the embryonic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Towy
The River Towy ( cy, Afon Tywi, ) is one of the longest rivers flowing entirely within Wales. Its total length is . It is noted for its sea trout and salmon fishing. Route The Towy rises within of the source of the River Teifi on the lower slopes of Crug Gynan in the Cambrian Mountains. Flowing through the steep hills of the Tywi Forest, it forms the boundary between Ceredigion and Powys. The river flows generally south-westwards through Carmarthenshire, passing through the towns of Llandovery and Llandeilo. Its total length is . with numerous tributaries that include the Cothi, Gwili, Brân, and Doethie."First Water Resources Survey : Report", South West Wales River Authority (1970), pg. 41; Table 1. In Carmarthen, it is joined by a substantial tributary, the Afon Gwili, at Abergwili. The estuary meets Carmarthen Bay east of the Pendine Sands along with the River Taf and both branches of the River Gwendraeth. The estuary was guarded by Llansteffan Castle, a 12th-century ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carmarthen
Carmarthen (, RP: ; cy, Caerfyrddin , "Merlin's fort" or "Sea-town fort") is the county town of Carmarthenshire and a community in Wales, lying on the River Towy. north of its estuary in Carmarthen Bay. The population was 14,185 in 2011, down from 15,854 in 2001, but gauged at 16,285 in 2019. It has a claim to be the oldest town in Wales – ''Old Carmarthen'' and ''New Carmarthen'' became one borough in 1546. It was the most populous borough in Wales in the 16th–18th centuries, described by William Camden as "chief citie of the country". Growth stagnated by the mid-19th century as new settlements developed in the South Wales Coalfield. History Early history When Britannia was a Roman province, Carmarthen was the civitas capital of the Demetae tribe, known as Moridunum ("Sea Fort"). It is possibly the oldest town in Wales, recorded by Ptolemy and in the Antonine Itinerary. The Roman fort is believed to date from about AD 75. A Roman coin hoard was found nearby in 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crymych
Crymych () is a village of around 800 inhabitants and a community (population 1,739) in the northeast of Pembrokeshire, Wales. It is situated approximately above sea level at the eastern end of the Preseli Mountains, on the old Tenby to Cardigan turnpike road, now the A478. The village developed around the former Crymmych Arms railway station on the now-closed Whitland to Cardigan Railway, nicknamed ''Cardi Bach'' (Little Cardi). Crymych, which is twinned with Plomelin in Brittany, has an elected community council. The village has given its name to an electoral ward of Pembrokeshire that encompasses the villages of Crymych itself and Eglwyswrw. The community includes Hermon, Glandwr, Glogue and Llanfyrnach. History The name Crymych translates into English as ''crooked stream'' referring to the River Taf which rises in the high ground above the village and takes a sharp turn in the valley at the north end of the village. Evidence of prehistoric occupation in the communi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fishguard
Fishguard ( cy, Abergwaun, meaning "Mouth of the River Gwaun") is a coastal town in Pembrokeshire, Wales, with a population of 3,419 in 2011; the community of Fishguard and Goodwick had a population of 5,407. Modern Fishguard consists of two parts, Lower Fishguard and the "Main Town". Fishguard and Goodwick are twin towns with a joint Town Council. Lower Fishguard is believed to be the site of the original hamlet from which modern Fishguard has grown. It is in a deep valley where the River Gwaun meets the sea, hence the Welsh name for Fishguard. It is a typical fishing village with a short tidal quay. The settlement stretches along the north slope of the valley. The main town contains the parish church, the High Street and most of the modern development, and lies upon the hill to the south of Lower Fishguard, to which it is joined by a steep and winding road. The west part of the town that faces Goodwick grew in the first decade of the 20th century with the development of Fish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
