"314.75"^^ . "Coal. Stratified bedrock. Occurs onshore. Deposited during the Duckmantian Substage (Carboniferous Period) (318-314.75 Ma BP)."@en . "Frog Lane Coal (South Wales)"@en . "Frog Lane Coal (South Wales)"@en . . "Coal."@en . . . . . "stable"@en . "318.0"^^ . . . . "FRGL"@en .