Tasmania is the tiny little island in the lower right corner (usually omitted when the map of Australia is shown):
This is not fair, because it is probably the most beautiful and diverse bit. In January we had the opportunity to visit this remote place and do some diving and a lot of driving.
Collecting shells is difficult as the water is cold and good places are hard to access. We were using 7 mm wetsuits and heaps of weights to stay down because there always is quite a bit of surf. My main target was to find out more about the elusive Notocypraea subcarnea, whose identity was only recently revealed. The real subcarnea is missing in almost all collections.
what you probably have: 
Notocypraea comptonii var. casta (3 shells on left) or pale forms of angustata (on right)
The true subcarnea differs by its large marginal spots, a faint narrow interrupted middorsal band and the posterior end of the columellar side which is denticulate instead of ridge-like as in angustata and comptonii:
The true subcarnea is a rare species whose validity has been confirmed by DNA studies, it seems to be endemic to Tasmania where two variations occur: the callused southern form (top) and the large and inflated northern form (bottom):
Notocypraea subcarnea. Top: South of Hobart, at 15 m. Bottom: Stanley, northern Tasmania, beached.
The other species of Notocypraea from Tasmania are quite spectacular:
From left to right: angustata, declivis, piperita, comptonii var. mayi and typical comptonii.
Another interesting thing about Tasmania is the history of its indigenous Aborigines, whose culture was far less developed than that of Australian mainland tribes. A summary may be found here: http://www.cwo.com/~lucumi/tasmania.html, and also here: http://jmm.aaa.net.au/articles/9639.htm
Facts in a nutshell: the Tasmanian Aborigines were basically still living in a neolithic age. They did not know how to make fire, but could use it when they found it. They made primitive stone tools. When the first Europeans came to Tasmania a genocide started which resulted in the extinction of the last full-blood Tasmanian Aborigine (a woman known as Truganini) in 1876. Today, there are descendants of women that were abducted to the islands north of Tasmania by sailors. I wanted to learn more about this sad story, see stone tools and other artefacts and was told that the Hobart Museum had a fabulous department for Aboriginal history. It is not allowed to take pictures at the Hobart Museum, but I have a drawing of the museum and a reconstruction of its Aboriginal display:
left: the Hobart Museum, right: the Aboriginal display.
At the Museum I asked where the famous Aboriginal displays had gone. I was told that the community of Tasmanians with Aboriginal heritage has objected against the way things were being displayed with the result that the whole department was closed for an uncertain period of time ("till things are being sorted out with them"). All I want to comment is that something only becomes extinct once it is erased from people's memories. Sadly, I could find nothing to remember about the indigenous people of Tasmania.