"stable"@en . . . . "Coal."@en . . "Jenkin Coal (South Wales)"@en . . "Coal. Stratified bedrock. Occurs onshore. Deposited during the Asturian Substage (Carboniferous Period) (310-307.5 Ma BP)."@en . . . "Jenkin Coal (South Wales)"@en . . "JNKN"@en . "310.0"^^ . "307.5"^^ .