. . "Higher Two Coal (South Lancashire)"@en . "HTCO"@en . "stable"@en . "Coal. Stratified bedrock. Occurs onshore. Deposited during the Langsettian Substage (Carboniferous Period) (319-318 Ma BP)."@en . . . "318.0"^^ . "Higher Two Coal (South Lancashire)"@en . . . . . "Coal."@en . "319.0"^^ . . "Higher Two Mines Coal [Obsolete: use HTCO]"@en .