Southerndown Coast is a Site of Special Scientific Interest (SSSI) in St Brides Major community, in the Vale of Glamorgan, South Wales.
The SSSI extends over 5 kilometres (3 miles) of south-west facing coastline, with rocky limestone cliffs, broad beaches and deeply fissured wave-cut platforms.
[1] The 153 hectares (380 acres) stretch of shore, cliff, cliff-top, and several short, steep valleys, are designated an SSSI for their geological and botanical value.
[2] The cliffs expose the Jurassic geological strata and some of the underlying Carboniferous Limestone, the latter dating from between 359 to c. 330 million years ago.
[2] A new deposition phase created more sedimentary rocks, including a red Triassic conglomerate, and a creamy white Jurassic limestone known as Sutton Stone, a freestone much sought-after for carved stonework, and so widely quarried where it occurs.