A few Palaeozoic outcrops and associated colluvium occur within the Western Plains where they were generally both islands in the Pliocene sea and elevated above the subsequent basalt flows. The inliers are predominantly granitic plutons that rise above the plain surface rather than those exposed by drainage line dissection. Aprons of colluvium often surround these inliers such as at Mount Kinross, and the western slopes of the You Yangs. West of Wallinduc, the low granitic hills of Mt Kinross (276 m) rise approximately 40 m above the surrounding plain. On the western flank they are covered by a thin veneer of sandy colluvium which merges with the Pliocene sands. On the Werribee Plains Granite Rock and the You Yangs form prominent granite hills above the plain. Flinders Peak (348 m) rises steeply to form the highest point of the You Yangs, nearly 300 m above the surrounding plain. The western flank is draped with sandy sediments comprising a complex mix of colluvium, Pliocene sands and alluvium. These sediments extend from almost the crest of the You Yangs to Hovell Creek along the edge of the volcanic plain. |