. "c.16m (24m in Ascog Borehole)."@en . . "BID"@en . "Mudstone, sandstone and siltstone and trace coal, conglomerate and seat-earth sandstone. Stratified bedrock. Occurs onshore. Deposited during the Visean Age (Carboniferous Period) (346.7-330.3 Ma BP)."@en . "Base sharp, probably erosional, on the Clyde Sandstone Formation (top of Inverclyde Group), which is characterised by presence of pedogenic limestone and lack of coal seams."@en . "Top is marked by the overlying Clyde Plateau Volcanic Formation. May be transitional, with interbedding of sedimentary rocks with lava flows."@en . . "Birgidale Formation"@en . . "stable"@en . . "346.7"^^ . . . . "Birgidale Formation"@en . "Grey mudstones, sandstones and seatearths with coal seams; non-marine."@en . "330.3"^^ .