The COPLEY 1:250 000 map area includes the northern Flinders Ranges and the southern part of the Willouran Ranges. It is bounded to the west by the Lake Torrens Sunkland and, to the east, by the Lake Frome Plains. A thick sequence of older Precambrian metasediments intruded by Carpentarian alkali granites is exposed in the Mount Painter Province in the north-east of the area. The crystalline basement is overlain by a complete succession of folded Adelaidean and Cambrian sediments. Diapirs originating from the Lower Callanna Beds intruded this sequence during sedimentation. Palaeozoic granites intruded Lower Adelaidean units in the Mount Painter Province. Coal deposited in the Late Triassic is now exploited as a source of power. Thin fresh water sequences of Jurassic sands and clays were locally deposited. Transgressive marine Lower Cretaceous sandstones were deposited in the Frome Embayment. Marginal faulting in Tertiary times resulted in the accumulation of thick sequences of sands and clays in the Pirie Torrens Basin and Frome Embayment. Piedmont gravels were deposited during uplift of the ranges in Pleistocene times. Increasing aridity resulted in the development of the Recent erosion cycle and the formation of aeolian sand dunes.