Sarn y Bwch
Sarn y Bwch,, is one of three parallel reefs extending beneath the sea into Cardigan Bay from the west coast of Wales. The causeway, probably a medial moraine is made of glacial deposits left by receding ice sheets at the end of the last ice age. It is sometimes called Sarn y Bwlch, 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. To the north is the causeway of Sarn Badrig, whilst to the south is Sarn Gynfelyn, which extends from near Aberystwyth.
