. . . "stable"@en . "Overlain by pale green-grey mudstones of the Dolgau Mudstones Formation."@en . . . . . "Laundry Mudstone Formation"@en . "Mudstones and siltstones."@en . "Fron Frys Formation"@en . "Mudstone and siltstone. Stratified bedrock. Occurs onshore. Deposited during the Llandovery Epoch (Silurian Period) (443.1-432.9 Ma BP)."@en . "Fron Frys Formation"@en . "25 m."@en . "443.1"^^ . "Fron Frys Slates [Obsolete: use FFR]"@en . "Overlies mudstones of the Laundry Mudstones Formation."@en . "432.9"^^ . "FFR"@en . . .