On the way down to Port Arthur last week I took a small detour to see the tesselated pavement at Eaglehawk Neck. It's a very beautiful spot and really does look like tiles rather than a natural phenomenon. You can read about how it was formed in this post on the Exploring The Earth blog.
On the way out of Port Arthur I stopped at several other coastal formations: Tasman Arch, Devil's Kitchen, the blowhole and Remarkable Cave. I have to admit I was underwhelmed, but I'm sure that was only because I'd been spoiled by what I'd seen on the Three Capes Track. They would be pretty spectacular in the right sea conditions. Or maybe there's only so much dolerite you can look at in a week.