650 million years ago, Dolomite was deposited here, though "here" is a rather elastic term on the geological time scale as we shall see.

450 million years ago, Tasmania was at the equator. 250 million years ago it was near the south pole, still as part of a super-continent. 85 million years ago it began to separate from Antarctica and this area underwent a period of uplift helping to expose the dolomite mentioned at the start of our tale. As I said, "here" is an elastic concept.

10 million years ago, rain fell. The rain was mildly acidic due to the absorption of carbon dioxide. This helped create channels in the rock. However the same carbon dioxide which helped make the rain acidic was incorporated into calcite. The results? What you see a small part of here. Newdegate Cave (named after the then-Governor of Tasmania, the only easily accessible dolomite cave in Tasmania running about 1.6km long and descending to 40 metres underground.

Fast forward to 1916. Tree gatherers cut down a tree. The tree falls across an opening in the rock. They had discovered the cave, which was opened to the public as an attraction in 1939, and which we visited in 2012; about 650 million years after the initial rock was laid down.

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