wherever in eastern Australia two unreduced plateau 

 masses exist side by side at variable altitudes a fault or 

 sharp t'ulil separates them. The irrand.-a rvmiples of fault- 

 in-- appear to have occurred at the edge of the continental 

 shelf. By this action the outer edge of the continent appears 

 to have been carried down to ocean depths. 1 The date of 

 this may be assigned to the close of the Pliocene or the 

 commencement of the Pleistocene. 



It will be seen that this warping action has been most 

 pronounced opposite to those points where the highlands 

 have been raised most abruptly. Thus along the southern 

 portion of New South Wales where the mountains are 

 highest and where their distance is least removed from the 

 ocean, there the opposite condition of affairs is found to that 

 off the central portion of the Queensland coast. The next 

 most important flexing and faulting has resulted in the 

 formation of the continental shelf. 



The origin, however, of this topographical feature has 

 been dealt with at length by Iledley, and only a brief note 

 is made here of it. A warp and Idling appears to have deter- 

 mined this feature. As the result of that movement a por- 

 tion of the old coast was submerged. " Wave base " was 

 formed and the coast was attacked at the same time that 

 the land was deeply dissected by the rejuvenated land 

 streams. The products of such erosion were carried beyond 

 " wave base" to form a plain of sedimentation the while the 

 sea advanced on the land to form a submarine shelf. Later 

 came the subsidence during the Human Period by which 

 action the Pleistocene shelf was deeply drowned and the 

 recent shore line was depressed for several hundreds of 

 feet. By such action the shelf may be seen to be due to 



' For a general discussion of continental borders see the masterly 

 treatment by Chamberlin and Salisbury in their Geology, in, pp. 526, 528. 

 8 Hedley, C. (a). 



