ABSTRACT
The Mount Dandenong Volcanics outcrop over an area of about 150 square kilometres and form the prominent landscape feature known as the Dandenong Ranges, centred some 50 kilometres east of the city of Melbourne. The Mount Dandenong Volcanics rest on a basement of sandstones, siltstones and shales forming the Late Silurian – Early Devonian Melbourne and Humevale Formations. The Dandenong Ranges represent a remnant of the Triassic erosion surface which also includes the high country between Warburton, Healesville and Mount Torbreck. The major volcanic units of the Dandenongs Complex, with the exception of the youngest unit, were emplaced, not as lavas, but as pyroclastic flows. The Coldstream Rhyolite outcrops along the western and northern edges of the Dandenong Ranges and is best seen in quarries at Montrose and Coldstream. Despite the resistance to erosion shown by the Mount Dandenong Volcanics, they are deeply weathered in parts.
