60 W. R. BROWNE. 



If we accept Andrews' theory that the Shoalhaven as it 

 now exists antedates the Kosciusko uplift and kept its 

 seaward course against the slow uprising of the coastal 

 area, then it seems highly probable that the Kangaroo was 

 brought into being subsequent to, and as a consequence of 

 that uplift. 



It seems nbt unlikely that investigation of the Hunter 

 River and its tributaries would afford illustration of some 

 of the principles enunciated above. Taylor maintains that 

 this river, by reason of the softness of the Permo-Oarbon- 

 iferous sediments through which much of its course lies, 

 has been enabled since Tertiary times to cut through 

 the former divide and capture the head waters of some of 

 the westerly-flowing streams. The theory is based, largely 

 at all events, on the fact that a number of the tributaries 

 of the Hunter form boathook bends with the main stream, 

 and a breached divide is believed to exist near Pokolbin, 

 the Wollombi Brook, Fal Brook, Upper Hunter and other 

 tributaries entering the Hunter "up stream." Apart from 

 the enormous amount of erosion with which this theory 

 would credit the Hunter as compared with other east- 

 flowing streams of similar age, there are a number of con- 

 siderations which may well give us pause before we accept 

 unreservedly the theory that a breached divide is indicated 

 by the peculiar arrangement of the tributaries. If we 

 neglect for the moment the "up stream" direction of 

 certain of the tributaries, the Hunter system is essentially 

 symmetrical, tributaries being developed on both sides, 

 and the main stream (that is the Lower Hunter plus the 

 Goulburn) having a remarkably straight course. If it can 

 be proved that the boathook bends are due to an adjust- 

 ment of the streams to structures, then the evidence for 

 the breached divide breaks down. 



