"Base of mudstone of above type, resting unconformably on shelly glauconitic limestone of the Lower Comley Limestones."@en . . "Not proved."@en . . "499.0"^^ . "Mudstone with subsidiary sandstone and siltstone. Stratified bedrock. Occurs onshore. Deposited during the Merioneth Series (Cambrian Period) (499-486.9 Ma BP)."@en . "Croft Member"@en . "Croft Member"@en . "486.9"^^ . "Black, fissile, mudstone interlaminated with micaceous siltstone and very fine-grained sandstone."@en . . . . . "CRFT"@en . "53.75m"@en . "stable"@en . . .