PRESIDENTIAL ADDRESS. 39 



scarps of all may be more nearly parallel with the coast, 

 but this point yet awaits investigation. Mr. Andrews has 

 well shown that in this latest epeirogenic uplift the maxi- 

 mum effect was produced at the mountain knot of the S.E. 

 corner of Australia where the meridional direction of flexing 

 met the cross flexing of the Bassian lines (op. eit., pp. 431-2). 



The recent epeirogenic uplift which has produced the 

 present Main Divide and coast line and accentuated the 

 continental shelf has the form of a gentle wave with its 

 steeper side directed to the Pacific, a fact emphasized by 

 Hedley. Hence for some time past the tendency has been 

 for the Divide to be forced inland, that is westwards, 

 through the steeper eastern rivers capturing the upper 

 portions of the watersheds of their more sluggish western 

 neighbours. Quite recently a downward joggle has taken 

 place for a considerable distance along the coast, especially 

 marked along the seaward edge of the great coal basin. 

 This depression has amounted to about 200 feet. A very 

 recent negative movement of the strand-line to the extent 

 of about 15 feet is so general around Australia as to suggest 

 that it may have been due to a eustatic negative move- 

 ment of the whole ocean surface in the Southern Hemi- 

 sphere, due to some such cause as a locking up of sea water 

 in the snowfields and glaciers of the Antarctic following 

 on after extreme deglaciation during an interglacial epoch. 



We thus see in New South Wales a marked example of 

 development of two sets of tectonic lines, the older an 

 orogenic set of strong folds with numerous normal and some 

 overthrust faults in each case directed inwards towards 

 that master warp the great central coal-field, the newer 

 set, of an epeirogenic nature, is a gentle flex, the hinge 

 parallel to the continental shelf, coast line, and present 

 Main Divide; but the normal faults with downthrows away 

 from the main axis of upheaval in many cases show T by their 



