. "Coal. Stratified bedrock. Occurs onshore. Deposited during the Asturian Substage (Carboniferous Period) (310-307.5 Ma BP)."@en . . . . "310.0"^^ . . "307.5"^^ . "Brynwhilach Two-Feet Coal (South Wales)"@en . "stable"@en . . . "BW2F"@en . . "Brynwhilach Two-Feet Coal (South Wales)"@en . "Coal."@en .