In Welsh the island is named after Saint David (Dewi Sant), the patron saint of Wales. It was the home of his confessor, Saint Justinian. The nearest large settlement is the city of St David's.
The island has a diverse geology for a relatively small area; it comprises sedimentary, volcanic and intrusive igneous rocks dating from the early Palaeozoic Era. The larger part of the north of the island is formed from mudstones of the Tetragraptus Mudstone Formation (also known as the 'Penmaen Dewi Shale Formation' and again as the 'Road Uchaf Formation' (sic) after the Rhod Uchaf locality on the island's east coast). However Carnysgubor stands proud to their west as it is formed from a more resistant microtonalite intrusion. In contrast the coastal cliffs between Trwyn-drain-du and Trwyn-Sion-Owen and also between Trwyn Ogof Hen and Rhod Uchaf are formed by sedimentary rocks, the mica-rich Lingula Flags and the sandstones and mudstones of the Ogof Hen Formation. The rock strata are typically steeply tilted and commonly faulted.
Southern end of Ramsey Island
Running NW–SE across the centre of the island from Aber Mawr to the vicinity of The Bitches is a band of late Arenig age tuffs and 'pencil slates' assigned to the Aber Mawr Formation. Its boundary with the sediments to the north is a fault.
The south of the island is dominated by a rhyolite intrusion as are the islets off its southern coast. To the west of the Ramsey Fault which runs from Aber Mawr to Porth Lleuog, is Carnllundain which is formed from the tough rhyolitic tuffs of the Carn Llundain Formation. These tuffs arose as volcanic ash falls, ash flows and turbidite deposits. Smaller areas of dark grey mudstones interbedded with debris flows grouped together as the Porth Llauog Formation occur around the margins of the rhyolite. Part of the southern margin of the inlet of Aber Mawr is characterised by the mudstones and sandstones of the Trwyn Llundain Formation, a part of the Solva Group of Cambrian rocks.[3][4]
Archaeology
Surveys in the 1990s and more recently discovered evidence of prehistoric cairns, field systems, barrows and other anomalies which suggest human activity on the island dates back up to 5,000 years.[5] Mediaeval sites include a holy well and cemetery from the 9th century.[6]
Recorded history
From 1082, the island was part of the cantref of Dewisland under the control of the bishops of St David's. In the 12th century, it was a place of pilgrimage; St Tyfanog's Chapel existed up to the 1600s, when it was described as "decayed", and there may also have been a chapel to St Justinian.[7]
In the 13th century, the island was reported to be fertile, producing beef, sheep, goats, wheat, barley and oats. In the 14th century, 100 acres (40 hectares) of the island supported horses, cattle and sheep. Rabbits, rushes, heath and birds' eggs were harvested. A farmhouse, corn mill and lime kiln were recorded in the 16th century, but the farm building was a ruin by the early 19th century. The mill and kiln were in operation until the early 20th century, and in 1905 the island was sold into private hands and ceased being an ecclesiastical holding.[6] A new farmhouse was built early in the 19th century, and was Grade II listed by Cadw in 1992.[8]
Ramsey has the most important grey seal breeding colony in southern Britain, with over 400 seal pups born each autumn.[9] In October 2017 the remnants of Hurricane Ophelia were responsible for some 90 seal pup deaths.[10]
With a permanent population of just two human residents, the RSPB Warden and Assistant Warden who live in a farmhouse there, the island is otherwise uninhabited. Tourist boats sail around the island and a ferry service run by Thousand Islands Expeditions operates from Easter to 31 October from St Davids Lifeboat Station on the mainland.[11]
Ramsey Sound
The Bitches in Ramsey Sound, with the farmhouse on RamseyYnys Cantwr seen from Ramsey IslandYnys Eilun (r) and Pont yr Eilun (just visible, l), from Ynys CantwrYnys Gwelltog, viewed from the sea
The waters around the island have significant tidal effects, and tidal waterfalls occur between The Bitches.[12][13] The asymmetrical underwater flow can be 3.8m/s (12ft/s) northward (flood) and 1.9m/s (6.2ft/s) southward (ebb), with some turbulence. The sound reaches some 66 metres (217 feet; 36 fathoms) deep, although a tidal island called Horse Rock protrudes from the water at low tide;[14] the name of the rock was recorded as early as 1583, on an Elizabethan map.[15]
A 400kW tidal power turbine project was planned from 2014[16][17][18][19] and the first turbine of three was installed in December 2015.[20] Unfortunately the turbine developed faults shortly after installation, and the developer Tidal Energy Ltd was placed into administration in October 2016.[21]
Ramsey Island is surrounded by a number of smaller islands, islets and rock clusters, including:
Meini Duon (Black Rocks) is the name given to three sea rocks approximately 5⁄8 mile (1.0 kilometre) south of Ramsey Island,[22] not far from the Bishops and Clerks. They are made of acid intrusive rock,[23] and are the furthest south-west of the group of small islets and rocks off this coast.[24]
Ynys Cantwr (Precentor's Island; formerly owned by the precentors of St David's.[25]), a small tidal island south of Ramsey Island. Its highest point is 54 metres.[26]
Ynys Eilun (5 acres (2 hectares),[27] length 850 feet (260 metres)[28]) and Pont yr Eilun are two islets about 1⁄4 mile (400 metres) east of Ynys Bery.[29] Visiting the island is not easy because of its difficult landing.[30] The surrounding waters are swept by a northeast current caused by Ynys Eilun itself.[31]
Ynys Gwelltog (Grassy Island; 56 metres, 184 feet),[32] a tidal island, in the past considered suitable for pasturing two sheep.[33]
Grassholm or Grassholm Island is a small uninhabited island situated 13 kilometres (8 mi) off the southwestern Pembrokeshire coast in Wales, lying west of Skomer, in the community of Marloes and St Brides. It is the westernmost point in Wales other than the isolated rocks on which the Smalls Lighthouse stands. Grassholm is known for its huge colony of northern gannets; the island has been owned since 1947 by the Royal Society for the Protection of Birds, and is one of its oldest reserves. It reaches 42 metres (138 ft).
The Preseli Mountains, also known as the Preseli Hills, or just the Preselis, is a range of hills in western Wales, mostly within the Pembrokeshire Coast National Park and entirely within the county of Pembrokeshire.
A tidal island is a raised area of land within a waterbody, which is connected to the larger mainland by a natural isthmus or man-made causeway that is exposed at low tide and submerged at high tide, causing the land to switch between being a promontory/peninsula and an island depending on tidal conditions.
Strumble Head is a rocky headland in the community of Pencaer in Pembrokeshire, Wales, within the Pembrokeshire Coast National Park. It marks the southern limit of Cardigan Bay. Three islands lie off the head: Ynys Meicel – 112 feet (34 m) – Ynys Onnen and Carreg Onnen.
South Stack is an island situated just off Holy Island on the northwest coast of Anglesey, Wales.
Ynys Llanddwyn is a small tidal island off the west coast of Anglesey, northwest Wales. The nearest settlement is the village of Newborough.
Ynys Bery is a small island south of Ramsey Island, Pembrokeshire, Wales, in the community of St David's and the Cathedral Close.
The Bishops and Clerks are a group of rocks and islets, approximately 1+1⁄2 miles (2.4 km) west of Ramsey Island, Pembrokeshire, Wales.
The Marros Group is the name given to a suite of rocks of Namurian age laid down during the Carboniferous Period in South Wales. These rocks were formerly known as the Millstone Grit Series but are now distinguished from the similar but geographically separate rock sequences of the Pennines and Peak District of northern England and northeast Wales by this new name.
The Caerfai Group is a Cambrian lithostratigraphic group in west Wales. The name is derived from Caerfai Bay on the north coast of St Brides Bay on the Pembrokeshire coast where the strata are well exposed in coastal cliffs. This rock succession has previously been known variously as the Caerfai Series, Caerfai Formation and Caerfai Beds and largely ascribed to the British regional stratigraphic unit Comley Epoch, though these terms are now obsolete.
St Davids and the Cathedral Close is a community in western Pembrokeshire, Wales. It comprises the city of St Davids and its surrounding rural area. It was established in 1987.
The Hells Mouth Grits, formally defined and renamed the Hells Mouth Formation by Young et al., is a geological formation composed of Cambrian Greywackes in the south west part of St. Tudwal's Peninsula. Equivalent to the Rhinog Formation in the Harlech Dome, the grit beds exposed at St Tudwal's are very uniform in lithology and thickness when traced along the outcrops, with a gradual thinning southwards. They exhibit the characteristic textures and structures of greywackes but differ from the normal type in being relatively well sorted and commonly laminated. Intercalated mudstones are more variable both in thickness and in lithology and contain laminated mudstones rich in sponge remains. The sandstones have sharply defined bases, often bearing sole structures and occasionally loaded. Sandstone dykes cut down from the bases of some beds and extend through up to 0.6 m of underlying siltstones. The sandstones may form sheets up to 4 m thick, although a bed thickness of up to 1m is more usual, and have been interpreted as turbidites deposited by currents from the northeast.
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.
The coastline of Wales extends from the English border at Chepstow westwards to Pembrokeshire then north to Anglesey and back eastwards to the English border once again near Flint. Its character is determined by multiple factors, including the local geology and geological processes active during and subsequent to the last ice age, its relative exposure to or shelter from waves, tidal variation and the history of human settlement and development which varies considerably from one place to another. The majority of the coast east of Cardiff in the south, and of Llandudno in the north, is flat whilst that to the west is more typically backed by cliffs. The cliffs are a mix of sandstones, shales and limestones, the erosion of which provides material for beach deposits. Of the twenty-two principal areas which deliver local government in Wales, sixteen have a coastline, though that of Powys consists only of a short section of tidal river some distance from the open sea. Its length has been estimated at 1,680 miles (2,700 km).
The geology of Pembrokeshire in Wales inevitably includes the geology of the Pembrokeshire Coast National Park which extends around the larger part of the county's coastline and where the majority of rock outcrops are to be seen. Pembrokeshire's bedrock geology is largely formed from a sequence of sedimentary and igneous rocks originating during the late Precambrian and the Palaeozoic era, namely the Ediacaran, Cambrian, Ordovician, Silurian, Devonian and Carboniferous periods, i.e. between 635 and 299 Ma. The older rocks in the north of the county display patterns of faulting and folding associated with the Caledonian Orogeny. On the other hand, the late Palaeozoic rocks to the south owe their fold patterns and deformation to the later Variscan Orogeny.
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