638 SAND-MOVEMENT ON THE NEW SOUTH WALES COAST, 



present physiographical features of special interest, sufficient to 

 form the subject of another paper. It is enough here to state 

 that there are no indications of sand-movement of more than 

 ordinary interest, until Wollongong is reached in lat.34° 25^ '. 



Below Botany the effect of the littoral current, already much 

 lessened by the sudden change in the direction of the shore-line 

 below Port Stephens, becomes less pronounced. 



The reaction caused by the impact of the powerful north-east 

 current from the Southern Ocean is beginning to be felt; and as 

 we travel southwards, the outline of the coast indicates more and 

 more clearly the absence of sand-movement. The outline of 

 the beaches becomes a flatter curve, which is a sure indication of 

 a sluggish current. Current-observations made at Port Kembla 

 and Wollongong by the author, show a weak northerly beach- 

 current caused by Port Kembla headland; which extends only as 

 far as the entrance to Tom Thumb Lagoon. Here it is met by 

 the southerly current moving the sand southwards from Wollon- 

 gong, and the relative strengths of these two currents determines 

 the position of the lagoon-entrance. 



Lake Illawarka.— The entrance to Lake Illawarra is forced 

 to the south by moving sand until Windang Island and the 

 adjacent high ground are met with. In times of drought this 

 entrance is entirely blocked, and remains so until the welcome 

 rains so raise the level of the enclosed water as to burst the 

 sand-dam, when the old struggle for mastery is renewed. A very 

 similar state of affairs exists at Coila Lake in lat. 36° 03', Burra 

 Lake and Wagonga Inlet, and several other places on the South 

 Coast. At Moruya River the entrance is forced to the south in 

 like manner, and other small rivers and creeks, and lagoon- 

 entrances have their channels sometimes on the north, at other 

 times on the south, and, occasionally, as at Womboyn River, in 

 the middle of a sandy beach. 



The evidence of sand-movement on the coast certainly becomes 

 less as we travel to the south, and below Montague Island it 

 becomes quite insignificant; and this can only be attributed to 



