On the physiography of Northeastern Australia. \\ 



proaches the coast, so does the divide. Where the divide retreats 

 from the shoreline, so does the niargin of the shelf. Froin this it is 

 inferred that a broad shelf serves as a buttress to that portion of the 

 continent that lies behind it. Sheltered by this buttress, radial rivers 

 persist as relies from the peneplaia epoch. As an example, attention 

 is directed to the Burdekin and Fitzroy Rivers, the longest rivers of 

 Eastern Australia. which discharge upon the broadest shelf." (Page 37.) 



In a more detailed review preceding to the suinmary we read: 

 (Page 35.) „It is suggested that the last geological cycle culminated 

 at some post-miocene date with the réduction to a peneplain of most 

 of Eastern Australia. Since a marginal river would lack the requisite 

 slope to flow and carve on a peneplain, those were the days of ra- 

 dial drainage." . . . „The coast would hâve extended then for some 

 distance seawards of the présent position. The Thomson and the Car- 

 pe nter Deeps, though already in existence, had not attained their 

 présent depth or breadth and had lapsed into a state of inactivity." 



„A new cycle, the présent, was inaugurated by the development 

 of energy in the Thomson and Carpenter Deeps." ... „A strip of 

 unsunken shelf of Cape Capricorn now lies wedged between the pé- 

 riphéries of the two océan basins. Only at this corner has radial 

 drainage surviverl. Within its range of action each deep has replaced 

 radial by marginal rivers. Undulations pulsating from these abysses 

 are considered to hâve broken back the coast line and ridged up 

 ranges in the coastal districts of New South Wales and Queensland 

 respectively." 



And yet more detailed in respect to the Burdekin and Fitzroy 

 rivers: (Page 19.) „The longest rivers of Eastern Australia. the Fitz- 

 roy and the Burdekin, occur opposite the broadest expanse of the 

 shelf. I suggest that the breadth of the shelf has preserved the length 

 of these rivers and présents it as a submarine buttress maintaining a 

 buttressed area. Probably this part of the shelf continues to exist 

 rather from the avoidance than from the résistance of pressure. Fe- 

 stoons of islands and a dissected coast indicate that subsidence has 

 occurred. So that the escape from pressure, even within this broa- 

 dest shelf has been partial, not complète. The outline of the shelf 

 and the islands that it carries shew that it cannot be an amalgamated 

 delta and thus the conséquence rather than the cause of the rivers." 

 „Protected by their submarine buttress the Fitzroy aud the Burdekin 

 more nearly represent primitive radial drainage than any other, 

 Australian stream flowihg into the Pacific. The plain on which they 



