Note on the isostatic background of Tasmanian physiography.

Tasmanian physiography is so closely connected with the great occurrences of dolerite (diabase) that a correct understanding of the one is essential for the deciphering of the other. Every worker in geology in Tasmania has made some contribution towards the elucidation of the problem, and this paper merely carries our knowledge a little further.<br>The statements here contained are not proved; and await further confirmation.<br>To summarise, then, the physical outline of Tasmania is framed on blocks of country elevated to varying altitudes and consisting of relatively soft sediments with sills of very hard igneous rock intruded at various horizons. Previous to this elevation a definite topography had been eroded, the igneous rock modifying this considerably, and this topography was elevated or not according to its position. In the course of the elevation, again, the igneous rock modified the lines of break, and after elevation it largely controlled the rate of erosion. Subsequent to this elevation, the agents of-erosion, chiefly frost, snow, and ice, on the highlands have moulded the details of the landscape, and some slight faulting has added a few features locally.