"Sapropelite. Stratified bedrock. Occurs onshore. Deposited during the Brigantian Substage (Carboniferous Period) (330.9-330.3 Ma BP)."@en . . "DOSH"@en . "Doupster Oil Shale"@en . "330.3"^^ . . . . . "Sapropelite."@en . . . "stable"@en . . "330.9"^^ . "Doupster Oil Shale"@en .