310 REPORTS OF RESEARCH COMMITTEES. 



The report presented herewith consists of short statements by 

 various writers of the work done in the various States and the 

 Dominion of New Zealand — Sussmilch for New South Wales, 

 Richards and Jensen for Queensland and the Northern Ten-itory, 

 Fenner and Chapman for Victoria, Ward and Fenner for South 

 Australia, Jutson for Western Australia, and C. A. Cotton for 

 New Zealand — these beinor introduced by a very brief note on the 

 Geographical Unity of Australasia and the associated islands. 



GENERAL. 



' Andrews considers that Australia and the outlying island-rings 

 constitute a portion of the greater geographical unit of the Pacific. 

 This Australasian fragment has a fivefold division consisting" of: — 



(i) A low plateau known as Western Australia. 



(ii) A block, relatively sunken, forming South Australia and 

 the Northern Territory. 



(iii) A ring of j^lat^au, plain, and coast, known as Eastern 

 Australia. 



(iv) A complex area of inland seas, comprising the Tasman, 

 Coral, Java, Timor, and Arafura examples. 



(v) A compound ring of islands separated by ocean depths and 

 forming high vclcanie piles and plateaux of ccral and 

 sedimentary rocks in various stages of dissection. 



Of these. Western Australia., according to Jutson, forme a compact 

 plateau, with shattered margins rising from 1,000 feet in the 

 south-west to 2,^000 and 3,000 feet above sea-level in the north- 

 eastern portions. Very few structural gaps are recorded from 

 this great block. No. ii, or the central region, is lowlying in 

 general, but is brolcen by fault blocks arranged in two sets, one 

 north and sovith and the other east and west. 



The eastern side of Australia consists of plains bounded by 

 plateaux arranged parallel to the coast from Thursday Island to 

 the mountains of south-western Victoria. This plateau system is 

 narrower, but much higher than that of Western Australia, and, 

 moreover, it is not so ccnipact as the latter, inasmuch as it is 

 broken by erosional or structural gaps, as at Townsville, Rock- 

 hampton, Toowocmba, Cassilis, and along the BendigO' line. 



The main structural gap may be coiisidered to be that of Bass' 

 Straits. Most of the gaps are arranged radially from South-Wes- 

 tern Australia as a centre. The inland seas represent areas more 

 depressed than that of Central Australia, nevertheless somewhat 

 parallel to it. The outlying island-rings mark plateaux narrower, 

 but higher, than the Eastern Australian types. Neverthe- 

 less, these plateaux are separated from each other by radial de- 

 pi'essions as from a centre in South- Western Australia. The de- 

 pressions are oceanic in depth. 



