South Stack ( cy, Ynys Lawd) is an island situated just off Holy Island on the northwest coast of

Anglesey Anglesey (; cy, (Ynys) Môn ) is an island off the north-west coast of Wales. It forms a principal area known as the Isle of Anglesey, that includes Holy Island across the narrow Cymyran Strait and some islets and skerries. Anglesey island ...

, Wales.

Geology

South Stack is an island known as a

sea stack A stack or sea stack is a geology, geological landform consisting of a steep and often vertical column or columns of rock in the sea near a coast, formed by Coastal_erosion#Wave_action, wave erosion. Stacks are formed over time by wind and wate ...

. It was formed by the

wave erosion Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms. The landward ...

of sedimentary rocks that once connected the island to the mainland. The area is known geologically as the

South Stack Formation The South Stack Formation is a sequence of Cambrian, Cambro-Ordovician (Furongian to Tremadocian) metasedimentary rocks exposed in northwestern Anglesey, North Wales. The outcrop of this formation at South Stack was chosen as one of the top 100 g ...

. Its strata includes

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

s and interbedded shales which have been contorted by large folds and crumples. The folds can be seen in the

seacliff Seacliff comprises a beach, an estate and a harbour. It lies east of North Berwick, East Lothian, Scotland. History The beach and estate command a strategic position at the mouth of the Firth of Forth, and control of the area has been con ...

s (best viewed from the steps leading down to the lighthouse). Thick beds of pure Holyhead

Quartzite Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tec ...

, which forms the bulk of

Holyhead Mountain Holyhead Mountain (''Mynydd Twr'' in Welsh: from ''(pen)twr'', meaning "tower") is the highest mountain on Holy Island, Anglesey, and the highest in the county of Anglesey, north Wales. It lies about two miles west of the town of Holyhead, and s ...

, lie above these folded

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

s. Recent studies suggests the rocks appearance was caused by large scale earth movements which is not a part of the normal sedimentary process; however, this theory remains controversial. Similar evidence of upthrusts can be seen in the cliffs to the south of South Stack. The fascinating geology of South Stack has been chosen as one of the top 100 geosites in the United Kingdom by

Geological Society of London The Geological Society of London, known commonly as the Geological Society, is a learned society based in the United Kingdom. It is the oldest national geological society in the world and the largest in Europe with more than 12,000 Fellows. Fe ...

, for its display of small-scale folding.

Lighthouse

South Stack Lighthouse The South Stack Lighthouse is built on the summit of a small island off the north-west coast of Holy Island, Anglesey, Wales. It was built in 1809 to warn ships of the dangerous rocks below. History The lighthouse has warned passing ships of t ...

, which was completed in 1809, is sited above the sea on South Stack. Its lamp tower is -tall and the lighthouse complex covers . There are over 390 stone steps and 10 metal steps down to the footbridge. Originally the only way to cross to the island was in a basket suspended from a hemp cable. In 1828 an iron suspension bridge was built, it was replaced in 1964 with a steel cable truss bridge. However, in 1983 it had to be closed to the public due to safety concerns. After a new aluminium bridge was built, the lighthouse was reopened to the public in 1997. It is now a popular destination, attracting thousands of visitors every year.

Nature reserve

The island's cliffs are part of the South Stack Cliffs RSPB reserve which are home to an estimated 8,000 nesting birds during the breeding season. An RSPB visitor centre (with

bird hide A bird hide (blind or bird blind in North America) is a shelter, often camouflaged, that is used to observe wildlife, especially birds, at close quarters. Although hides or hunting blinds were once built chiefly as hunting aids, they are now commo ...

) is located at Elin's Tower on the mainland. Birds and marine life seen from the centre include choughs, peregrine falcons, and

kestrels The term kestrel (from french: crécerelle, derivative from , i.e. ratchet) is the common name given to several species of predatory birds from the falcon genus ''Falco''. Kestrels are most easily distinguished by their typical hunting behaviou ...

as well as

harbour porpoise The harbour porpoise (''Phocoena phocoena'') is one of eight extant species of porpoise. It is one of the smallest species of cetacean. As its name implies, it stays close to coastal areas or river estuaries, and as such, is the most familiar ...

grey seal The grey seal (''Halichoerus grypus'') is found on both shores of the North Atlantic Ocean. In Latin Halichoerus grypus means "hook-nosed sea pig". It is a large seal of the family Phocidae, which are commonly referred to as "true seals" or " ...

Risso's dolphin Risso's dolphin (''Grampus griseus'') is a dolphin, the only species of the genus ''Grampus''. Some of the closest related species to these dolphins include: pilot whales (''Globicephala'' spp.), pygmy killer whales (''Feresa attenuata''), melon ...

s and bottlenose dolphins.

Tidal wave project

In 2019, proposals to develop a 'West Anglesey Demonstration Zone' tidal energy project at South Stack were submitted under the

Transport and Works Act 1992 The Transport and Works Act 1992 (TWA) was established by the Parliament of the United Kingdom to provide a system by which the construction of rail transport, tramway, inland waterway and harbour infrastructure could proceed in the UK by or ...

to the

Welsh Government , image = , caption = , date_established = , country = Wales , address = , leader_title = First Minister () , appointed = First Minister approved by the Senedd, ceremonially appointed ...

for planning consent. As the development will come within 500 metres of the South Stack SSSI, concerns have been expressed about the visual impact on the Anglesey

Area of Outstanding Natural Beauty An Area of Outstanding Natural Beauty (AONB; , AHNE) is an area of countryside in England, Wales, and Northern Ireland, that has been designated for conservation due to its significant landscape value. Areas are designated in recognition of ...

and the Holyhead Mountain Heritage Coast along with the resultant impact on the tourism, recreation and fishing sectors. The developers have identified that seabird and mammal populations would be affected within the Holy Island Coast

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 a ...

and

Special Protection Area A Special Protection Area (SPA) is a designation under the European Union Directive on the Conservation of Wild Birds. Under the Directive, Member States of the European Union (EU) have a duty to safeguard the habitats of migratory birds and certa ...

along with the North Anglesey Marine Special Area of Conservation. Most notably bottlenose dolphin and

would likely be affected, whilst

razorbill The razorbill, razor-billed auk, or lesser auk (''Alca torda'') is a colonial seabird and the only extant member of the genus '' Alca'' of the family Alcidae, the auks. It is the closest living relative of the extinct great auk (''Pinguinis im ...

and

common guillemot The common murre or common guillemot (''Uria aalge'') is a large auk. It has a circumpolar distribution, occurring in low-Arctic and boreal waters in the North Atlantic and North Pacific. It spends most of its time at sea, only coming to land to ...

will be severely impacted. The RSPB is concerned that the

colony on South Stack could be wiped out.

Walking trails

Part of the Anglesey Coastal Path, which is a

long-distance footpath A long-distance trail (or long-distance footpath, track, way, greenway (landscape), greenway) is a longer recreational trail mainly through rural areas used for hiking, backpacking (wilderness), backpacking, cycling, horse riding or cross-cou ...

around the island of

, passes South Stack. The Cybi Circular Walk around

has long and short variants; the short walk is long and takes around two hours to complete. Travelling from the Breakwater Country Park, other sites along the way are the North Stack Fog Signal station, Caer y Tŵr, and Tŷ Mawr

Hut Circle In archaeology, a hut circle is a circular or oval depression in the ground which may or may not have a low stone wall around it that used to be the foundation of a round house. The superstructure of such a house would have been made of timber an ...

Media

South Stack's natural beauty has been used in photography and literature. The cover photo for

Roxy Music Roxy Music are an English rock band formed in 1970 by Bryan Ferry—who became the band's lead vocalist and principal songwriter—and bassist Graham Simpson. The other longtime members are Phil Manzanera (guitar), Andy Mackay (saxophone ...

's ''

Siren Siren or sirens may refer to: Common meanings * Siren (alarm), a loud acoustic alarm used to alert people to emergencies * Siren (mythology), an enchanting but dangerous monster in Greek mythology Places * Siren (town), Wisconsin * Siren, Wisc ...

'' album was taken directly below the central span of the bridge on a slope on the south side, by Graham Hughes in August 1975. In 2010 a French comic entitled ''Les Gardiens des Enfers'' ("The Guardians of Hell") was published. Its story is mainly set in South Stack lighthouse in 1859. The cover and the first pages can be seen on the publisher's website.''Les Gardiens des Enfers''
/ref>

References

{{Islands of Anglesey Islands of Anglesey Tourist attractions in Anglesey Trearddur