352 " ENDEAVOUR " SCIENTIFIC RESULTS. 



Phillip Island, and the deepest 53 fathoms, sounded in many 

 places by the " Endeavour," particularly northwards from 

 the mouth of the Tamar River. From diaL'ram .... it is 

 apparent this southern basin area was very wide and flat, 

 reminding one of low-lying marsh land of great extent, while 

 the channel towards the Victorian border had much steeper 

 grades laterally. 



When also taking into consideration that subsecpxent to the 

 " flood " a much greater amount of erosion has taken place 

 in the northern and western area than in the central area, it 

 may be assumed that the more confined river valley silted 

 up to a much greater extent than the southern basin, and 

 this will to a large extent account for the present disparity 

 in levels. But another factor may also be taken into account, 

 viz., as it is assumed that the general '" dii)])ing " of the 

 Continent has been in a south-east direction with a pivot or 

 hinge somewhere to the north-west, it follows that by such 

 a mode of de]iression the southern or Tasmanian section 

 would sink more than the northern or Victorian area. The 

 distance in a south-east direction from the north-western 

 shallowest bend of the channel to the deeper central area is 

 approxiuiately one hundred and twenty miles, so that the 

 angle of depression in ordei' to equalise the whole dirt'crence 

 W'Ould only amount to approxiuiatelv 5' of arc, or at the rate 

 of 1 in 15.200. 



There is certainly no support for Dr. Xoetling"s suggestion 

 that a barrier appi'oximately one hundred and fifty feet above 

 the level of the central l)asin extended between King Island 

 and Western Port, and consequently there is i\o evidence of 

 his lake. 



l)n the contrary, we find that a ninnber of rivers from North 

 Tasmania would converge tow^ards a centre (as indicated l\v 

 Noetling), l)ut instead of forming a gigantic lake they w^ould 

 join with a magnificent river running to the north, north-west, 

 and west along the present coast of Victoria, and ultimately 

 enter the oceai^i somewhere to the east of Cape Otway. Into 

 this river, which might suitably be named the Tamar Major, 

 would also flow' tributaries from the now extinct eastern and 

 western slopes of the Bass Strait basin, so the approximate 

 catchment area, extending from central Tasmania, in the 

 south and the Victorian Dividing Range (or further) in the 

 north, woixld cover more than 50.(KK) square miles, producing 

 150,000 millions of cubic feet of water for a rainfall of only 

 one inch. 



