1998 Bicentenary of Bass & Flinders-Bass Strait & Tasmania PNC. The circumnavigation of Van Diemen's Land by George Bass and Matthew Flinders begun in October 1798 and completed in January 1799, proved the existence of Bass Strait and finally established that Tasmania was an island. These findings had significant impact on the sailing time and safety of ships sailing from Europe to Australia. Featuring commemorative 50 cent and two 45c stamps. Please contact Adelaide Exchange Jewellers to find out more on this item.