. . "318.0"^^ . "Coal. Stratified bedrock. Occurs onshore. Deposited during the Duckmantian Substage (Carboniferous Period) (318-314.75 Ma BP)."@en . "314.75"^^ . . "Hams Coal (North Staffordshire)"@en . "HAMC"@en . "Hams Coal (North Staffordshire)"@en . . "Coal."@en . . . . . "stable"@en .