 It contains the Donaldson Formation (a marine fan), Savage Dolomite which contains stromatolites; Bernafai Volcanics containing albite epidote actinolite chlorite; Corinna Dolomite, and Tunnelrace Volcanics.Where the dolomite has been dissolved away over million of years it has left layers of very pure silica flour, an important mineral resource.The Dundas Element lowest level starts with the Oonah Formation with greywacke, dolomite and basic volcanics.