. . "Calcareous mudstone with subsidiary calcareous tuff and calcilutite. Stratified bedrock. Occurs onshore. Deposited during the Caradoc Series (Ordovician Period) (458.2-449.75 Ma BP)."@en . "Craig-Y-Glyn Group [Obsolete: use CGYG]"@en . . "CGYG"@en . "stable"@en . . . . "Calcareous mudstones. (Well stratified rhyolitic and calcareous ash, and pale blue bedded limestone; with calcareous shale and calcareous, blue mudstone and shale)."@en . "Craig-Y-Glyn Formation"@en . "449.75"^^ . "458.2"^^ . . . "Craig-Y-Glyn Formation"@en . "Greater than 300m in the Lwrch inlier."@en . "In faulted contact with mudstones of Llangynog Formation of Carodocian age."@en . "Not seen."@en .