. "A dull red, coarse-grained, pebbly, angular, lithic sandstone with clasts predominantly of fragments of volcanic rocks, and conglomerate."@en . . "At the base of the lowest conglomerate bed within the Whitehouse Conglomerate Formation or at the base of the Crawton Volcanic Formation where the Whitehouse Conglomerate Formation is absent."@en . . . . "Castle Hill Formation [Obsolete: use GNF]"@en . "Up to 300 m thick."@en . . . "Gourdon Formation [Obsolete: use GNF, RCC]"@en . "Sandstone with subsidiary conglomerate and pebbly (gravelly) sandstone. Stratified bedrock. Occurs onshore. Deposited during the Silurian Period - to - Early Devonian Epoch (Devonian Period) (443.1-394.3 Ma BP)."@en . . "443.1"^^ . "GNF"@en . . "stable"@en . "Gourdon Sandstone Formation"@en . "394.3"^^ . "Not exposed, but stratigraphically above the Tremuda Bay Volcanic Formation."@en . . . "Gourdon Sandstone Formation"@en . "Gourdon Harbour Sandstone Member [Obsolete: use GNF]"@en .