Editing Port Talbot (section)

===Bedrock geology===
South East of Port Talbot is dominated by [[Pennant sandstone]] which forms this high relief area including Mynydd Margam, Mynydd Dinas and the other mountains. The pennant sandstone is made up of two formations which are the Rhondda Member and Brithdir Member. The sandstone formed in [[Carboniferous]] swamps 300 million years ago. Pennant sandstone is a micacous sandstone which has a brown colouration with areas of red staining where iron from [[pyrite]] in coal has weathered creating a rust colouration.<ref>{{cite web |title=The Geological Society of London - A stroll along the prom – Swansea Bay |url=https://www.geolsoc.org.uk/GowerTour1 |website=www.geolsoc.org.uk |publisher=The Geological Society |access-date=26 October 2022}}</ref>

Lower land areas are predominantly Pennant sandstone within the [[South Wales Coal Measures Group]].{{citation needed|date=December 2016}}