Sarn Badrig, also spelled ''Sarn Padrig'' (

Welsh Welsh may refer to: Related to Wales * Welsh, referring or related to Wales * Welsh language, a Brittonic Celtic language spoken in Wales * Welsh people People * Welsh (surname) * Sometimes used as a synonym for the ancient Britons (Celtic peop ...

for '

St. Patrick ST, St, or St. may refer to: Arts and entertainment * Stanza, in poetry * Suicidal Tendencies, an American heavy metal/hardcore punk band * Star Trek, a science-fiction media franchise * Summa Theologica, a compendium of Catholic philosophy an ...

's causeway'), is one of several more or less parallel shingle reefs extending under the sea in

Cardigan Bay Cardigan Bay ( cy, Bae Ceredigion) is a large inlet of the Irish Sea, indenting the west coast of Wales between Bardsey Island, Gwynedd in the north, and Strumble Head, Pembrokeshire at its southern end. It is the largest bay in Wales. Geograp ...

on the west coast of

Wales Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...

. The causeway is made of

glacial deposits image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...

left by receding ice sheets at the end of the last

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...

. Sarn Badrig is the longest and most northerly of these, and extends south-westwards under the sea from Mochras Point, near

Harlech Harlech () is a seaside resort and community in Gwynedd, north Wales and formerly in the historic county of Merionethshire. It lies on Tremadog Bay in the Snowdonia National Park. Before 1966, it belonged to the Meirionydd District of the 197 ...

, parallel to the

Llŷn Peninsula The Llŷn Peninsula ( cy, Penrhyn Llŷn or , ) extends into the Irish Sea from North West Wales, south west of the Isle of Anglesey. It is part of the historic county of Caernarfonshire, and historic region and local authority area of Gwynedd. Mu ...

for a length of about 20 km, and can be seen at low tide. It is a hazard to shipping. A neighbouring causeway is that of Sarn y Bwch, which is close to

Tywyn Tywyn (Welsh: ; in English often ), formerly spelled Towyn, is a town, community, and seaside resort on the Cardigan Bay coast of southern Gwynedd, Wales. It was previously in the historic county of Merionethshire. It is famous as the loc ...

. Another example can be found at Sarn Gynfelyn, which is north of

Aberystwyth Aberystwyth () is a university and seaside town as well as a community in Ceredigion, Wales. Located in the historic county of Cardiganshire, means "the mouth of the Ystwyth". Aberystwyth University has been a major educational location in ...

. In Welsh legend it is one of the dykes which protected the drowned realm of

Cantre'r Gwaelod , also known as or ( en, The Lowland Hundred), is a legendary ancient sunken kingdom said to have occupied a tract of fertile land lying between Ramsey Island and Bardsey Island in what is now Cardigan Bay to the west of Wales. It has been des ...

Points of interest

External links

Cantre'r Gwaelod (The Lowland Hundred)www.geograph.co.uk : photos of Sarn Badrig
Reefs of Gwynedd Cardigan Bay Reefs of the Atlantic Ocean {{Gwynedd-geo-stub