In the forested far south beyond the Huon, Newdegate Cave is the largest dolomite cave open to visitors in Australia - a rarity, for most show caves form in limestone. Guided tours climb through its cathedral chambers past columns, shawls and the delicate straws that give the cave its character, all lit to show the warm colour of the stone. Nearby, a thermal springs pool holds warm water at a constant 28 degrees among the tree ferns, a welcome soak after the cool of underground. The drive south through tall wet forest is half the pleasure.