. . . "Middle Old Red Sandstone [Obsolete: use BKI, INS]"@en . "Black Isle Sandstone Group"@en . "394.3"^^ . . "stable"@en . . "Red sandstone sequence incorporating the Den Siltstone, Kilmuir Conglomerate and Raddery Sandstone Formations."@en . "BKI"@en . . . "Unconformable base of Old Red Sandstone sequence."@en . "+ 2000m."@en . "Sandstone with subsidiary conglomerate and siltstone. Stratified bedrock. Occurs onshore. Deposited during the Mid Devonian Epoch (Devonian Period) (394.3-378.9 Ma BP)."@en . "378.9"^^ . . . . "Black Isle Sandstone Group"@en . "Unconformable base of the Balnagown Sandstone Group."@en .