Sedimentary rock found in the basin originate from over 14 million years ago, ceasing after this time. The area contains fan-glomerates as a result of fluctuating climatic conditions involving periods of high rainfall and steam discharge alongside calm weather. The region contains coarse ridges as a result of constant erosion. The Mount Lofty Ranges contain sharp slopes, generated due to an uplift in the earth's surface of over 500m along its western segments.