"HAP"@en . . . . . "stable"@en . . "Happendon Coal (Douglas)"@en . "Coal."@en . "318.0"^^ . "319.0"^^ . . . . "Happendon Coal (Douglas)"@en . "Coal. Stratified bedrock. Occurs onshore. Deposited during the Langsettian Substage (Carboniferous Period) (319-318 Ma BP)."@en .