The ignimbrite forms escarpments, with the lower-lying land being underlain by tuff. The Deakin Volcanics can be found south of the Deakin Fault between Belconnen and Charnwood and MacGregor. It also is found through Weston Creek north of Chapman and Fisher, through Woden apart from Curtin, and across to Hume, and south through Tuggeranong. The different colours found in the rocks are due to weathering, the red being from hematite, and the green from clay minerals such as celadonite. The pink crystals are potash feldspar.