PRESIDENT’S ADDRESS. 739 
and in places almost suddenly, to the 100-fathom line, especially on 
the western and southern side of Tasmania. Beyond this there 
are few soundings, but from those given the following statements 
may be noted. 
The 50-fathom line is distant about 40 miles in a south-westerly 
direction from Cape Otway; at 10 miles further off is the 
100-fathom line ; at 20 miles further the depth is over 900 fathoms ; 
finally, at 150 miles from Cape Otway,-in the same direction, 
there is a sounding of over 2,300 fathoms. 
Similarly, in a south-easterly direction from the Ninety-mile 
Beach in Gippsland, the 50-fathom and 100-fathom lines are 
distant 50 and 70 miles respectively. 
South-easterly from Cape Pillar, in the extreme south of 
Tasmania, the soundings of 50, 100, and 1,000 fathoms are distant 
respectively about 5, 8, and 50 miles. 
The lines of 50 and 100 fathoms soundings off the Murray mouth 
are distant therefrom about 100 miles, the two lines being 
apparently no more than 5 miles apart. At 100 miles further 
south there is a sounding of 2,840 fathoms. 
The general conclusions derivable from a study of these charts 
are that the 50-fathom line represents a submerged plateau con- 
necting Victoria approximately from Cape Howe to Cape Otway 
with Tasmania. From it there is a more rapid slope to the 
100-fathom line, and thence a still greater slope into ocean depths. 
An elevation of 300 feet would therefore lay dry a tract of com- 
paratively level country between Victoria and Tasmania, rising 
to a central ridge on the eastern side. The plateau would mainly 
lie not more than 100 to 200 feet above sea-level, but in places 
rising up to 3,000 feet. On the western side a deep bend to the 
north-east indicates the former channel of a river conveying the 
combined waters of all streams and rivers which now debouch 
between Cape Otway and Wilson’s Promontory, whose deposits 
probably account for the unusual distance between the 50 and 
100 fathom line, from the embouchure down to Cape Sorrell. 
The plateau of low-lying land thus indicated flanking the 
eastern side of the chain of denuded and eroded mountains, where 
peaks are now islands in Bass Strait, would probably resemble the 
sandy and swampy country covered with dwarf scrub and coarse 
sedges which border Corner Inlet and separate Wilson’s Pro- 
montory from the Gippsland coast ranges. 
A great delta is indicated by these soundings, extending between 
Kangaroo Island and Cape Jaffa, a hundred miles beyond the 
present Murray mouth. 
The former elevation of the land surface in the newer volcanic 
era may not unreasonably be held to be connected with the 
conditions shown by the soundings in Bass Strait. If so, the 
