From Warrnambool we drove west along the coast some more, but not far. Just a few miles away is Tower Hill, a fascinating environment well worth the stop.

The southern part of the Australian state of Victoria is made of limestone. It's even called the "Limestone Coast." That's how you get cool formations like the sea stacks I described in the previous post. But underneath Victoria there's a plume of hot rock, and it breaks through to the surface here and there. That's why the Deep Blue resort in Warrnambool had a hot spring, and that's how Tower Hill was formed.

Tower Hill is an old volcanic caldera — actually, not an old caldera, a very recent caldera. Archaeologists have found human-made tools buried in ash deposits from its last eruption, and date them from about 5,000 years ago. The main crater seems to have formed about 38,000 years ago, when hot magma pushed up into water-bearing strata and caused a titanic steam explosion. So the Tower Hill caldera isn't what you expect from a volcano, because it's not a mountain. It's a big hole in the ground with a fairly low ridge of ash and debris around the edge.

What's inside the ridge is a small lake, with a couple of islands, and a belt of wetland around the edge. And all of that is a wildlife refuge. It's full of birds and animals — we saw a wallaby and a couple of koalas from the trail, seemingly unafraid of visiting foreigners. 

I had expected our visit to be a brief stop to see the crater, but we would up walking the nature trail for more than an hour, and it was well worth the stop. 

One interesting detail about Tower Hill is that the modern town of Tower Hill starts just on the other side of the crater rim to the north. As we hiked through an isolated paradise of native plants and wildlife, we could still hear dogs barking, leaf blowers, and traffic noise from the town. I'm not sure if I would be so sanguine about building my home literally on top of a volcano — but millions of people in Hawaii, Japan, Italy, Indonesia, and Iceland seem quite comfortable with the idea.

From Tower Hill we took a long drive through cattle country to the town of Mount Gambier, which boasts its own set of natural wonders: they've got their own volcanic caldera (currently in use as a water reservoir) and a limestone sinkhole, what would be called a cenote in Mexico. Both are gorgeous, and from the edge of the reservoir there's a lovely view of the ocean to the south.

In Mount Gambier we lunched at a Hungry Jack restaurant, which is the Australian version of Burger King. It's . . . very much like a Burger King. I happen to rather like Burger King (I like to be able to get onion rings instead of French fries) so it was fine. I don't know if I ever have to go back to a Hungry Jack again, but I'm glad I tried it.

Our course from Mount Gambier led straight north to the town of Penola, which lies in the Coonawarra wine region of Victoria. We walked around and visited one winery that evening, but made an early night of it. The next day (Wednesday May 14) we got up early and drove up to the Narracoorte Cave World Heritage Site. 

Narracoorte is a set of limestone caves carved by groundwater. Nothing special about that, except for two things: these particular caves had vertical shafts opening to the surface, so that animals frequently fell into them. The caves are relatively close to the surface so the creatures weren't shattered by the fall, but there was no way out so they would starve to death and leave their bones in the cave. Thousands of animals, over thousands of years. It's not a "fossil bed" — it's a fossil mine. Paleontologists have been working away down there for decades and still have barely sampled the incredible amount of animal remains. There are dozens of species of extinct kangaroos, lizards, snakes — everything.

Except bats. The caves never had much of a bat population. That's important, because when the first British settlers explored the caves in the 19th Century, they were looking for bat guano to mine as fertilizer. If they had found some, the Narracoorte Guano Company would be a minor footnote in the history of the region, and the caves would be just another dangerous abandoned industrial site. But there were no bats, there was no guano, which meant that the only people interested in digging around the Narracoorte caves were paleontologists.

We spent half the day at Narracoorte, taking the guided cave tour and poking around, then drove back toward Penola and spent the afternoon doing tastings at one winery after another. All the wineries make good stuff, and almost none of them ship to the USA. Alas.

Penola is not what one would call a center of nightlife, so once again we turned in early, preparing for an epic driving day on Thursday.