Geology nerding...
The whole chunk of Victoria from the middle bit westwards is/was a volcanically active region. It goes across into SA... Whole bunch of dormant/extinct volcanoes. Mt Alexander, Mt Franklin (which my parents can see from their house), Mt Macedon, all that stuff. Nothing's really erupted since about 6,000 years ago, but that's not that long ago, geologically speaking. There's still tectonic deformation taking place across the region, so it's still technically active, and the volcanoes are technically dormant, rather than extinct. The prevailing theory at uni was that a hot spot caused most of them (like Hawaii), and if the hot spot has moved on, it's not likely they'll start erupting again. (My dad does like to joke about watching Mt Franklin blow up from a safe distance, though.
)