Mount Clay

This information has been obtained from the report: Eruption Points of the Newer Volcanic Province of Victoria by Neville Rosengren. This report was published in 1994 and was prepared for the National Trust of Australia (Victoria) and the Geological Society of Australia (Victorian Division). The review of eruption points was based on an earlier unpublished manuscript Catalogue of the post-Miocene volcanoes of Victoria compiled by O P Singleton and E B Joyce (Geology Department, University of Melbourne 1970).

Location:	38 12 59S 141 43 00E (external link); 7221-4-2 (Fitzroy River) 614698. 20 km NE of Portland. Tower Road.
	Heywood
Land Tenure/Use:	Private land at summit. Crown land on lower slopes. Grazing on degraded and bare summit. Telecommunications tower repeater station. Forest on public land. Little outcrop.
Type 10:	Other (composite scoria and tuff volcano, with lava flow).
	Mount Clay is a single volcano of scoria and tuff, with lava flows to the north-east and south of the summit. The summit and slopes are gullied, especially the southern face. The volcano rests on a basement of limestone which appears to have been uplifted along an east-west axis and tilted towards the north. The south-facing slope (south of Mount Clay) is a prominent east-west escarpment covered by lava flows and tuff.
	186 m; 175 m.
Regional:	This is a major example of a complex eruption point producing abundant tuff but not related to a maar crater. The relationship between volcanic activity and the tectonics of the faulted limestone block is of interest. This may be one of only two known localities in Victoria where volcanicity was accompanied by (and may have caused?) uplift of a limestone basement block (the other is Staughton Hill). The complexity of the site is a combination of several geological and geomorphological processes including volcanicity, faulting and marine and sub-aerial erosion.
Class 3:	This is a large site and there are no sensitive areas that are threatened by present land use. Continuation of present land use will retain the site values.
References:	Coulson, A. 1941. The volcanoes of the Portland district. Proceedings of the Royal Society of Victoria 53, pp. 394-402. Boutakoff, N. 1963. The geology and geomorphology of the Portland area. Geological Survey of Victoria Memoir 22. Ollier, C.D. & Joyce, E.B. 1964. Volcanic physiography of the Western Plains of Victoria. Proceedings of the Royal Society of Victoria 77. Pp 357-376.

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