The Clwyd Limestone Group is a stratigraphic unit (a defined sequence of rock layers) of Chadian to Brigantian age (Lower Carboniferous) found in north Wales. It forms part of the Carboniferous Limestone Supergroup.[1] Its most extensive outcrop is along the length of the Clwydian Range, immediately to the east of its crest, between Llandegla and Prestatyn. A further though more fragmented outcrop extends in an arc along the western margins of the Vale of Clwyd north from Rhyd-y-meudwy, west of Ruthin and then northwest to meet the coast at Llanddulas. It is prominently exposed at the Great Orme and Little Orme near Llandudno and again in three areas of eastern and southern Anglesey, together with a small area to the south of the Menai Strait between Bangor and Y Felinheli. The outcrop also extends southwards from Llandegla to form an impressive scarp at Creigiau Eglwyseg north of Llangollen and south again, to the west of Oswestry to Llanymynech Hill on the Powys/Shropshire border.[2]
In Anglesey, it comprises the Loggerheads Limestone Formation and overlying Cefn Mawr Limestone Formation. These are supplemented at the Great Orme by an underlying Llanarmon Limestone Formation and an overlying Red Wharf Limestone Formation, both of which are dolomitic, at least in part. In the Clwydian Range, a lowermost Foel Formation is succeeded in turn by the Llanarmon Limestone, Leete Limestone, Loggerheads Limestone and Cefn Mawr Limestone formations. These are capped by the limestones and sandstones of the Minera Formation which completes the sequence. The outcrop in the west of the Vale of Clwyd is similar but narrower and lacking the Foel Formation. The outcrop south of Llandegla comprises only the Leete, Cefn Mawr and Minera units. There is a small faulted inlier of the Clwyd Limestone around Ffrith to the northwest of Wrexham and a smaller outlier of the Clwyd Limestone just to the west of Corwen.
^"Clwyd Limestone Group". The BGS Lexicon of Named Rock Units. British Geological Survey. Retrieved 8 November 2020.
^"GeoIndex Onshore". British Geological Survey. Retrieved 8 November 2020.
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The ClwydLimestoneGroup is a stratigraphic unit (a defined sequence of rock layers) of Chadian to Brigantian age (Lower Carboniferous) found in north...
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Cheshire Plain from the east, with the Vale of Clwyd to the west. The range is covered in moorland, limestone outcrops, and hillforts. Distinctive landmarks...
the Clwyd Area, was pioneered by Stuart Cathcart. The crag remains a favourite for group usage, with school parties and military outward-bound groups both...
(Parc Cenedlaethol Eryri) and the Clwydian Range and Dee Valley (Bryniau Clwyd a Dyffryn Dyfrdwy), known for its mountains, waterfalls and trails, wholly...
Statistics". www.nomisweb.co.uk. Retrieved 3 August 2021. Vale of Llangollen, Clwyd-Powys Archaeological Trust Dee Valley, Froncysyllte to Newbridge Archived...
origin to rising sea levels in the post-glacial period. The Severn, Dee and Clwyd estuaries experience tidal bores under certain conditions. Estuaries typically...
(north of Betws-y-Coed) and a part of the Berwyn a Mynyddoedd De Clwyd / Berwyn and South Clwyd Mountains SAC. The Pen Llyn a'r Sarnau / Lleyn Peninsula and...
dating from the Permian period occur in North Wales underlying the Vale of Clwyd and extend into the northeastern fringes of the country from the larger...
Llanfyllin". Retrieved 17 April 2015. "Church of St Myllin,Llanfyllin". The Clwyd-Powys Archaeological Trust. Retrieved 19 April 2015. "St Myllin's Church...
the main range lie the Arenig Group, Cadair Idris and the Berwyn Mountains. In the northeast of Wales, between the Clwyd Valley and the Dee Estuary, lies...
Crossing to the junction with the Vale of Clwyd line just north of Denbigh was lifted in 1963. However, limestone powder traffic continued to originate at...
Kingdom. Originally built under an act of Parliament of 1804 to move limestone from the quarries of Mumbles to Swansea and to the markets beyond, it...
Iron Age settlements over many hundreds of years on the slopes of the limestone headland, known to seafarers as the Great Orme and to landsmen as the...
received approval for limestone extraction in 1950 and developed in subsequent decades to become an important regional producer of limestone by the early 1980s...
Denbighshire and Caernarvonshire, which are covered respectively by the Clwyd-Powys Archaeological Trust (CPAT) and Gwyneth Archaeological Trust. Scheduled...
144–145 "The Clwyd-Powys Archaeological Trust – Projects – Archaeology in the Forest-Prehi". The Clwyd-Powys Archaeological Trust website. The Clwyd-Powys Archaeological...
English as "White Pass", perhaps referring to the white limestone cliffs in the area. These limestone outcrops were more prominent, in the north of the village...
The county of Denbighshire is in north-east Wales, occupying the Vale of Clwyd and the uplands to the west, east and south. There are 168 scheduled monuments...
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