Sarn y Bwch, (

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 'buck's causeway'), is one of three parallel reefs extending beneath the sea into

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 ...

from 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, probably a

medial moraine A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice shee ...

is made of glacial deposits 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 ...

. It is sometimes called ''Sarn y Bwlch'' ('the causeway of the pass'), but this form is later and less common than ''Sarn y Bwch''. Sarn y Bwch is the central of the three, extending south-westwards from near

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 ...

. To the north is the causeway of

Sarn Badrig Sarn Badrig, also spelled ''Sarn Padrig'' (Welsh for 'St. Patrick's causeway'), is one of several more or less parallel shingle reefs extending under the sea in Cardigan Bay on the west coast of Wales. The causeway is made of glacial deposits le ...

, whilst to the south is Sarn Gynfelyn, which extends from near

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 ...

External links

Cantre'r Gwaelod (The Lowland Hundred)
Reefs of Gwynedd Cardigan Bay Reefs of the Atlantic Ocean {{Gwynedd-geo-stub