"319.0"^^ . . . . "Coal. Stratified bedrock. Occurs onshore. Deposited during the Langsettian Substage (Carboniferous Period) (319-318 Ma BP)."@en . "BTQ"@en . "stable"@en . . . . "Bottom Three-Quarter Coal (Northumberland And Durham)"@en . . "Bottom Three-Quarter Coal (Northumberland And Durham)"@en . "318.0"^^ . . "Coal."@en .