"Aran Volcanic Group"@en . . "Up to 2.5km in the Cadair Idris district."@en . . "477.1"^^ . . "449.75"^^ . . "Aran Volcanic Group"@en . . . . "A mixed suite of basalts, rhyolites volcaniclastic and sedimentary rocks."@en . . "Drawn at the conformable upward passage of the Craig Cau Formation (Cadair Idris District) into turbiditic mudstones and siltstones o the Ceiswyn Formation. The top of the group is not seen in the Harlech district, where the highest formation represented is the Aran Fawddwy Formation, comprising felsic ash-flow tuffs."@en . . . "Overlies the Mawddach and Rhobell Volcanic groups, with unconformity in places. The base is drawn at the base of the quartzose sandstones of the Garth Grit Member (Allt Llwyd Formation), where it rests unconformably upon bedded felsic rocks of the Rhobell Volcanic Group."@en . . . "stable"@en . "Basalt, rhyolite, sedimentary rock based on grain size or crystal size and volcaniclastic rocks (both pyroclastic and reworked volcanic rocks). Stratified bedrock. Occurs onshore. Deposited during the Arenig Series - to - Caradoc Series (Ordovician Period) (477.1-449.75 Ma BP)."@en . . . . . . . "AVG"@en . . . .