Ardvreck Group

Ardvreck Group
Stratigraphic range: Lower Cambrian
Quartz arenite with skolithos burrows, the Pipe Rock of the upper Eriboll Formation, viewed on a bedding surface
Type	Group
Sub-units	Eriboll Formation, An-t-Sron Formation
Underlies	Durness Group
Overlies	Lewisian complex or Torridonian Supergroup
Thickness	up to 142 m
Lithology
Primary	quartzite, quartz arenite
Location
Region	Hebridean Terrane
Country	Scotland
Extent	Northwest Highlands
Type section
Named for	Ardvreck Castle

The Ardvreck Group is a stratigraphic group of early Cambrian age found in the Northwest Highlands of Scotland. It lies unconformably on gneisses of the Lewisian complex or sandstones of the Torridonian Supergroup. It consists of two formations, the basal quartzites and quartz arenites of the Eriboll Formation and the overlying dolomitic siltstones and sandstones and quartz arenites of the An-t-Sron Formation. It is overlain conformably by the Ghrudaidh Formation of the Durness Group. The Ardvreck Group was at one time known as the "Eriboll Group".