HomeAreasMt Cotterell

Mt Cotterell: Geological History

Western Region of Melbourne

‘The surface geology of much of the region is dominated by the remnants of Cainozoic volcanism, and there are numerous eruption points, and broad, moderately thick lava flows in the northern, central and western sectors.’ ‘The major lava-free areas are those such as the You Yangs, which had sufficient elevation to escape burial’

‘The most widespread geological material outcropping in the area is the basalt of the Newer Volcanics, ranging from 2.5 million to 5 million years ago. Individual flow thickness varies from 2 metres to over 10 metres, and the entire sequence is in places almost 100 metres thick.’ The flows originated from Mt. Cotterell (lava cone), Mt. Kororoit (scoria capped by lava), Greek Hill (mixture of basalt and scoria), Black Hill (Cowies Hill), Green Hill and Mt. Mary (lava and scoria cone) and Spring Hill (lava dome). Some of the tongue lava -flows from Mt. Cotterell were up to 10 kilometres long. ‘The bulk of the volcanic material is tough, dark, strongly olivine basalt. Scoria and and tuff (fragmental lava) is less common and is associated with higher and steeper volcanic hills such as’… ‘Mt. Bullengarook’.


Mt Cotterell

Mt. Cotterell at 205 metres in height ‘is the most massive of the Werribee Plains volcanoes and one of the largest ‘shield’ volcanoes inVictoria.’ Rosengren 1994

It’s commanding bulk is readily seen when viewed from a distance. Several major watercourses are sourced from it’s slopes. Two tributaries of Dry Creek arise from the southern and eastern slopes, and two of Davis Creek also from the southern slopes.  In the north the drainage extends to Kororoit Creek, and to the west, the Werribee River.