. . "Garnkirk Main Fireclay"@en . "320.0"^^ . "Garnkirk Main Fireclay"@en . "319.0"^^ . . . "GKFC"@en . "Bedrock. Occurs onshore. Formed during the Yeadonian Substage (Carboniferous Period) (320-319 Ma BP)."@en . . "stable"@en . . . .