"Bettws Mill Tuff Member"@en . "Stratified bedrock. Occurs onshore. Deposited during the Abereiddian Stage (Ordovician Period) (468-461.25 Ma BP)."@en . "Bettws Mill Tuff Member"@en . "468.0"^^ . . . . . . "461.25"^^ . . "stable"@en . . "BEMI"@en . .