Precambrian rocks which crop out only on southernmost parts of the area are described. They consist of poorly outcropping ?Umberatana Group and Willyama Complex. The latter includes late stage doleritic pegmatoid and granitoid intrusives and well defined metasedimentary sequence. This amphibolite grade sequence contains remarkable group of albitic, albite calc silicate, and albite quartz iron formation rocks, for which evaporite and modified volcaniclastic related origins are proposed; and argillites and lesser arenites deposited under shallow water, marine and / or nonmarine, partially anoxic conditions. Syngenetic sulphide minerals occur in various units, but most significantly in a single or multiple horizon which crops out as regional stratiform sulphide gossan hosting copper cobalt mineralization at Mount Howden and Dome Rock, and copper at Waukaloo.