‘Although classified as Newer Volcanics, these volcanoes are of the Pliocene age, and generally are much older than the Newer Volcanics of Western Victoria. Original volcanic features, such as stony rises and crater, have thus been modified by weathering and are less preserved here.’

‘Site Description: Mount Cottrell is a volcanic cone formed by the radial eruption of numerous lava tongues.’ Height is 205metres. ‘ The massive nature of this basalt cone is not readily appreciated when viewed from close quarters, but is readily apparent when seen from distant points such as the You Yangs.’ ‘The slopes are of low angle, apart from those at the summit where a hard dense basalt bluff 5-6 metres high surrounds a shallow crater.’

‘Significance: Regional. There ar two aspects to the significance of this site - the specific nature of the bluff and crater at the summit, and the extent of the radial flows. The cone is the most massive of the Werribee Plains volcanoes and gave rise to a number of distinct lava flows. The basalt rim is of particular interest as it has similarities to the cappings of the volcanoes of the Gisborne area.’

‘Geological Significance: Highly significant geological feature. The Mount is part of the Register of the National Estate, categorized as having State Significance by the National Trust of Australia (Victoria) and the Geological Society of Australia (Victorian Division),
1994. Mount Cottrell is the best example in Victoria of a lava shield with lava cone as summit. Quoted from the Rosengren (1994) in his inventory and evaluation of scientific significance,
The site was rated as having state significance due to its significance’ Rosengren 1994

‘The flows from this point’, this being Mt.Cotterell. ‘may have influenced the course of the Werribee River.’ Reference: Condon M.A. (1950) 

‘The Werribee River downstream of Bacchus Marsh basin has cut a gorge through an extensive lava field.  For the succession of basalt flows and interbedded pyroclastics the name ‘Exford Volcanics’ is proposed’.  Reference M. A. Condon 1950.

Bracketed quotes from:
Sites of Geological and Geomorpholgical Significance in the Western Region of Melbourne N.J. Rosengren 1986 unless stated otherwise.

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