619 



SAND MOVEMENT ON THE NEW SOUTH WALES 



COAST. 



By G. H. Halligan, F.G.S. 



(Plates lii.-liii.) 



The coast of New South Wales is 600 miles long, extending 

 from Point Danger, in South latitute 28° 09' and East longitude 

 150° 341', to Cape Howe in S. lat. 37° 30' and E. long. 150° 00'; 

 and as it closely approximates to a straight line, its general direc- 

 tion is about N.N.E. and S.S. W. 



There is undoubted evidence of the coastal strip having, within 

 very recent geological time, been submerged, either by a positive 

 movement of the ocean or a negative movement of the land, and 

 it is probable that this movement was to the extent of between 

 200 and 300 feet.* 



This fact makes the movement of sand and shingle on our coast 

 more complicated, and for that reason perhaps more interesting. 

 Subaerial denudation produces inequalities in the land surface, 

 and when the land is afterwards submerged the hollows thus 

 formed give rise to indentations in the coast, and these indenta- 

 tions exist for a considerable time before they are filled up by 

 sand and shingle drifting along the shore. 



When a coast is subjected to marine denudation during a period 

 of elevation or of negative movements of the ocean, a much more 

 simple class of coast will appear. The shore-line being largely 

 composed of sediment, the denudation curve will be quickly 



• David, T. W. E., B.A., F.R.S., "Anniversary Address to the Royal 

 Society of New South Wales, May, 1896," Journ. Proc. xxx., 1896, p. 57. 



