. "314.75"^^ . "Half Yard Coal (Warwickshire)"@en . . . . . "Coal."@en . "HAYD"@en . "318.0"^^ . . . . "Half Yard Coal (Warwickshire)"@en . "Coal. Stratified bedrock. Occurs onshore. Deposited during the Duckmantian Substage (Carboniferous Period) (318-314.75 Ma BP)."@en . "stable"@en .