500 NEW ZEALAND SOUND (AND LAKE) BASINS, 



contours of shore lines and river mouths are explained by terrific 

 streams of rare occurrence, the action of prevailing currents 

 carried on during the long years of inter-storm occurrences being 

 almost negligible in this great work. 



For the readier understanding of the present note a brief 

 summary of the late-geographical history of Eastern New South 

 Wales (also E. Australia) and South-Western New Zealand, as 

 understood by the author, is here furnished. 



i. Eastern New South Wales (also Eastern Australia). 



(a) Eastern New South Wales — as also doubtless the eastern 

 strip of Australia generally — has formed a geographical unit 

 since Cretaceous time. 



(b) Upper Cretaceous time appears to have been marked by 

 the development of a great plain of erosion. Monadnocks, how- 

 ever, attest to the existence of a still earlier plain of erosion. 



(c) An epeirogenic movement interrupted the final touches 

 which were being bestowed on the peneplain and carried the 

 plain to a considerable height above sea-level. 



(d) Valleys retreated headwards into the central plateau, 

 but, prior to their mature development, a gentle subsidence of 

 the central areas of former elevations supervened and the torrent 

 tracks were replaced by lakelets. In these were deposited many 

 plant remains to which various ages* such as Eocene, Miocene — 

 and even Pliocene in certain cases — have been assigned by eminent 

 palaeontologists and palseobotanists. 



(e) Subsidence still progressing, great fissuref eruptions of basalt 

 again and again inundated the sunken area and buried the 

 "leads." 



(f) A period of comparatively stable equilibrium ensued and a 

 gigantic plain of erosion was carved out of basalts, Tertiary 

 "leads" and the associated geologic complex alike. From its 



* Baron von Ettingshausen; Sir Frederick McCoy; Baron von Mueller; 

 Beginald A. F. Murray, pp.86-92. 



t T. W. E. David, (b) pp. 108-109; E. C. Andrews, (g) pp. 16-17. 



