344 " ENDEAVOUR " SCIENTIFIC RESULTS. 



in conjunction with still another factor, in many parts, but 

 particularly southwards from Port Jackson, the two ledges 

 are separated by a fairly abrupt and rocky wall, and the 

 impression is conveyed that the outer ledge is similar to the 

 inner, excepting for the greater depth (and corres|X)nding 

 difference of deposit). It may be conceived, therefore, that 

 the whole of the south-eastern jX)rtion of the Continent has 

 sunk to the extent of presenting the inner ledge as a relatively 

 new feature, Avhile previously the other was shallow enough 

 to be under the influence of the eroding factors, or, in other 

 words, the present deep water ledge formerly constituted the 

 shallow area, and the dry land extended seawards to the 

 present line of demarcation between the two ledges. At 

 present there are indications of slight elevation of the eastern 

 portion of the Continent, but there is also evidence that 

 formerly the south-east portion was much higher than at 

 present. A geologist, Mr. Griffith Taylor, once informed me 

 that in the interior of Australia he had discovered extinct 

 river beds flowing westward as continuations of the existing 

 rivers of the western slope. After descending the mountains 

 these streams have now all been diverted in a southerly 

 direction and ultimately discharge into the IMurray, whilst 

 formerly they evidently reached Lake Eyre and the South 

 Australian Gulf. A '' tilting " or depression of the south- 

 east corner would explain all this. 



