"c. 700 m: Lower unit: c. 0-165 m; Upper Unit c. 500 m (minimum)."@en . "Unconformable upon Lewisian Gneiss inlier (L); unconformity locally sheared."@en . . "Iona Group"@en . . . . . . . . . "720.0"^^ . "Torridonian [Obsolete: use T]"@en . "1000.0"^^ . "stable"@en . "Lower Unit: very coarse cobble-boulder conglomerate, interbedded with, and grading upwards a pebble conglomerate. Followed by a pink to grey coarse, arkosic sandstone, interbedded with thin mudstone. Upper Unit: interbedded fine-grained grey sandstone and thin dark mudstone beds with ripple laminations."@en . "Iona Group"@en . . "IONA"@en . "Colonsay Group"@en . "Not exposed - eroded."@en . "Metasandstone and metasiltstone and trace hornfelsed metasandstone, hornfelsed metasiltstone, hornfelsed mylonitic semipelite, metaconglomerate and mylonitic semipelite. Stratified bedrock. Occurs onshore. Deposited during the Tonian Period (Precambrian) (1000-720 Ma BP)."@en .