"BRSH"@en . "Faulted or unconformity."@en . "Probably 250m - 350m."@en . . . . . "Probably conformable with White-leaved Oak Shale."@en . "stable"@en . "Bronsil Shale Formation"@en . "Bronsil Shales [Obsolete: use BRSH]"@en . . "Mudstone. Stratified bedrock. Occurs onshore. Deposited during the Tremadoc Series (Ordovician Period) (486.5-477.1 Ma BP)."@en . . "486.5"^^ . . "Fissile silver-grey mudstone."@en . . "477.1"^^ . "Bronsil Shale Formation"@en .