. . . "BWTH"@en . "Blidworth and Top Hard Coal (Vale of Belvoir)"@en . . . "Top Hard Coal (South Yorkshire, Nottingham and Derby)"@en . . "stable"@en . "318.0"^^ . . . . "314.75"^^ . "Coal."@en . "Blidworth and Top Hard Coal (Vale of Belvoir)"@en . "Coal. Stratified bedrock. Occurs onshore. Deposited during the Duckmantian Substage (Carboniferous Period) (318-314.75 Ma BP)."@en .