"Flaggy semipelite and quartzite with subsidiary graphitic pelite. Stratified bedrock. Occurs onshore. Deposited during the Neoproterozoic Era (Precambrian) (1000-541 Ma BP)."@en . . . "Beinn Donn Quartzite Formation"@en . "541.0"^^ . "Beinn Donn Quartzite Formation"@en . . . "BDQU"@en . "Flaggy semipelite and quartzite with subsidiary graphitic pelite."@en . . . . . "1000.0"^^ . "stable"@en .