activities supervened and wide valleys or plains were 

 formed both in the basaltic masses and in the associated 

 geological complexes. 



The Tertiary closed with a vigorous uplift. Forces appear 

 to have been directed both from Central Australia radi- 

 ally outwards, and from the southern oceanic regions 

 toward Australia. In this way the continental edges 

 were upwarped until incoherence was established. At 

 this stage relief of the marginal strain on the continent 

 was obtained by faulting and Hexing in arcs parallel to the 

 oceanic depths. Tasmania acted as a horst, and against 

 it and the suboceanic creep the Victorian mountains and 

 the mountain knot at the south-eastern angle of Australia 

 were formed. In this region the faulting and flexing were 

 most pronounced. For this period of plateau formation 

 the name "Kosciusko" or "Plateau" Period is suggested. 

 It may be mentioned here in passing, that this southern 

 portion of the continent has had muclimore vigorous oscil- 

 latory movements in a vertical direction since early Tertiary 

 time than have other portions of the eastern continent. 



The rate of movement vertically was not rapid. The 

 Lower Hawkeshury appears to have kept pace with the 

 uplift, but at a distance from the shoreline area the 

 streams failed signally to do so. The plateaus indeed are 

 still undissected, excepting on their western and eastern 

 margins. The great fault blocks also have been only parti- 

 ally dissected by head ward working streams. 



Toward the close of the " Kosciusko" Period the upward 

 movement was rejuvenated and "valley in valley" forms 

 now characterise the valley bases. 



After the great faulting Period great basaltic displays 

 appear to have taken place in Victoria, Tasmania, Queens- 

 land, and probably also in New South Wales. 



