Rocks belonging to the upper part of the Adelaide System and the overlying Cambrian, outcrop in the eastern part of the Beltana area in the Nuccaleena Dome, and form the basement underlying the more recent sediments to the west. In the central and western areas they have been block faulted to form two partly connected basins in which Tertiary deposits accumulated. These are now completely masked by Recent sand and scree. Willouran rocks are exposed in the Beltana Diapir, and in faults radiating from the centre of the Nuccaleena Dome. Diapiric movement, during late Marinoan times, locally influenced sedimentation. Syngenetic lead and copper deposits are present at Ediacara. Elsewhere in the area copper is present both as stratiform and cross-cutting lodes which may be related to diapirism.