Complex sentence: One of the geologically rarities of South Wales is the coastline of Ogmore-by-Sea and Southerndown, as it made of cliffs composed of Sutton stone; a very rare freestone that is a banded mixture of lias limestone which contains large elements of carboniferous limestone.
Split into simpler sentences: One of the geological rarities of south Wales is the coastline of Ogmore-by-Sea and Southerndown. Its cliffs are composed of Sutton stone; a very rare freestone that is a banded mixture of lias limestone which contains large elements of carboniferous limestone.