"Calcareous mudstone. Stratified bedrock. Occurs onshore. Deposited during the Asbian Substage (Carboniferous Period) (337-330.9 Ma BP)."@en . . . . "Dykebar Marls"@en . "stable"@en . . "337.0"^^ . . . . "DYMR"@en . . "Calcareous mudstone."@en . "Dykebar Marls"@en . "330.9"^^ .