Castell Mawr is a large limestone rock that dominates the western shore of Red Wharf Bay in Anglesey, north Wales. It was probably once the site of an Iron Age fort, but today the rock is a protected refuge for nesting seabirds. [1]
It is located between the village of Red Wharf Bay and the promontory where St. David's Holiday Park is sited. The closest large villages are Pentraeth and Benllech.
The site is notable for being the only location on Anglesey displaying genuine karst development in a series of small caves and solutional cavities.
Castell Mawr was selected by the Countryside Council for Wales because of its geological interest, as it provides exposures of carboniferous limestone strata. The rock consists of limestone and sandstone layers, part of the Benllech Limestone formed during the Brigantian Stage of the lower Carboniferous period. The limestone was once mined and exported to other centres in the UK and Ireland. [2]
Benllech is a large village on the Isle of Anglesey in Wales. It is in the community of Llanfair-Mathafarn-Eithaf, which has a population of 3,382, making it the fourth largest settlement on the island of Anglesey. The name of Benllech village had been removed by the time of the 2011 census with the community being listed under Llanfair-Mathafarn-Eithaf with the electoral ward being listed under Llanddyfnan. The built-up area has a population of 2,236.
Ogmore-by-Sea is a seaside village in St Brides Major community in the Vale of Glamorgan, Wales. It lies on the western limit of the Glamorgan Heritage Coast of south Wales. The population in 2011 was 878.
Red Wharf Bay, also known as Traeth Coch, is a village and a wide sandy bay in the Anglesey Area of Outstanding Natural Beauty on the east coast of the island of Anglesey in Wales. The bay lies between the villages of Pentraeth and Benllech. It is also close to Castell Mawr Rock, thought to be the site of an Iron Age fort.
Carboniferous Limestone is a collective term for the succession of limestones occurring widely throughout Great Britain and Ireland that were deposited during the Dinantian Epoch of the Carboniferous Period. These rocks formed between 363 and 325 million years ago. Within England and Wales, the entire limestone succession, which includes subordinate mudstones and some thin sandstones, is known as the Carboniferous Limestone Supergroup.
Southerndown is a village in the Vale of Glamorgan, in south Wales. It is southwest of Bridgend, and within the St Brides Major community, close to Llantwit Major and Ogmore-by-Sea. It is mostly known for its beach which backs Dunraven Bay, which is a popular tourist destination during the summer months and since 1972 has been part of a Heritage Coast and is part of the Southerndown Coast SSSI. When the tide is out there is an expanse of sand and pools. The cliffs are an obvious example of sedimentary rock.
Dulas Bay is a small bay on the north east coast of Anglesey, north Wales, forming the boundary between Llaneilian and Moelfre communities. The bay is bordered by three beaches.
Ynys Dulas is a small island located off the north-east coast of Anglesey, Wales. It marks the most eastern part of the parish of Llaneilian.
The Red Wharf Bay branch line was a standard gauge railway line in Anglesey, Wales, a branch off the Anglesey Central Railway. It opened fully in 1909, but closed to passengers in September 1930. Freight operations continued until 3 April 1950, and the tracks were lifted during the summer of 1953.
The Isle of Anglesey is a county off the north-west coast of Wales. It is named after the island of Anglesey, which makes up 94% of its area, but also includes Holy Island and some islets and skerries. The county borders Gwynedd across the Menai Strait to the southeast, and is otherwise surrounded by the Irish Sea. Holyhead is the largest town, and the administrative centre is Llangefni. The county is part of the preserved county of Gwynedd.
Red Wharf Bay and Benllech railway station was the terminus station of the Red Wharf Bay branch line, which ran between Holland Arms and Benllech, off the Anglesey Central Railway.
Cors Erddreiniog National Nature Reserve is the largest of the Anglesey fens and was described by the former Countryside Council for Wales as the "Jewel in the crown of the Anglesey fens"
The Anglesey Coalfield is a minor British coalfield. Although it is situated in north-west Wales, this isolated coalfield on Anglesey is not usually considered to form a part of the North Wales Coalfield which lies in Flintshire and Denbighshire in north-east Wales although both measures were formed during the Carboniferous period. Stretching from Nant and Hirdrefaig in the Pentre Berw area along Cors Ddyga and under the sea at Malltraeth village which was called 'yr Iard' or 'Iard Malltraeth'. On the western side of the Afon Cefni lies Cors Malltraeth. It was named after Cwmwd Malltraeth (Commote) which was the old Welsh way of dividing the Isle of Mona by the Welsh Princes and the Church. Both coalfields measure around 9 miles long.
Southerndown Coast is a Site of Special Scientific Interest (SSSI) in St Brides Major community, in the Vale of Glamorgan, South Wales. It forms part of the Glamorgan Heritage Coast, bordered by the Monknash Coast to the southeast. The nearby villages are Southerndown and Ogmore-by-Sea. The SSSI extends over 5 kilometres of south-west facing coastline, with rocky limestone cliffs, broad beaches and deeply fissured wave-cut platforms.
Marian-glas or Marianglas is a small village and post town in Anglesey, north-west Wales. It lies between the larger villages of Moelfre and Benllech and just off the A5025. There is a large caravan park on the edge of the village and several camp sites. There is a church and pub but no shop. It has a memorial to those killed in the two world wars, including a list of 17 seamen from the Merchant Navy.
Llanbedrgoch is a hamlet and post town, a mile south of the town of Benllech and west of Red Wharf Bay, on the island of Anglesey, north Wales. The parish church is St Peter's Church, Llanbedrgoch, a Grade II* listed building that dates back to the 15th century.
Bwrdd Arthur, also known as Din Sylwy, is a 164-metre (538 ft) flat-topped limestone hill on the island of Anglesey, in Wales. Located on the eastern end of Red Wharf Bay, some 3 kilometres north west of Llangoed, it is noteworthy from the evidence of pre-historic occupation and as a Site of Special Scientific Interest designated for its botanical interest.
Llanfair-Mathafarn-Eithaf is a parish and community in Anglesey, Wales including the small seaside town of Benllech. The community population taken at the 2011 census was 3,382.
The Clwyd Limestone Group is a stratigraphic unit of Chadian to Brigantian age found in north Wales. It forms part of the Carboniferous Limestone Supergroup. 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.
The geology of Anglesey, the largest (714 km2) island in Wales is some of the most complex in the country. Anglesey has relatively low relief, the 'grain' of which runs northeast–southwest, i.e. ridge and valley features extend in that direction reflecting not only the trend of the late Precambrian and Palaeozoic age bedrock geology but also the direction in which glacial ice traversed and scoured the island during the last ice age. It was realised in the 1980s that the island is composed of multiple terranes, recognition of which is key to understanding its Precambrian and lower Palaeozoic evolution. The interpretation of the island's geological complexity has been debated amongst geologists for decades and recent research continues in that vein.