Llanddwyn Island has the best exposures of Precambrian
rocks in the southern block of Anglesey. This wall of sharp and jagged
rocks is on the north edge of the Island. Probably the most dramatic and
well known of the rocks on Llanddwyn are on the shoreline at the
entrance to the island. They are a kilometre north along the shore from
the car park in Newborough Warren. The rocks are basalt pillow lava of
the Gwna Group, which erupted beneath the late Precambrian to early
Erupting lava chilled quickly against the water with
the blobs of lava expanding like a balloon to form the shape we know as
pillow lava. In combination with the limestones and lavas, Llanddwyn
Island is one of the most spectacular field localities in the UK. The
rocks can explain the history and origin of the Earth.
Review Anglesey Geopark Llanddwyn Island.