BEACH FORMATIONS AT BOTANY BAY. 165 



large sand flat which the Northern mail-train passes over 

 near Woy Woy is a case in point. This area lies about 10 

 feet above high tide mark; it is in such a sheltered position 

 that it cannot be explained by the action of wind; it has 

 no sign of dune structure ; and, in company with the 

 numerous similar occurrences around Sydney it is covered 

 with forest growths. At Bondi the combination of the two 

 types may be seen. The low-lying area separating the 

 harbour from the ocean at this point is seen to possess a 

 base consisting of a sand flat, while its eastern or seaward 

 portion may be seen to be buried under high sand dunes of 

 wind origin. 



In all these topographical features it is the " element of 

 horizontality " which is so marked a feature. On the other 

 hand, this element is lacking in the marginal sand hills 

 which are known to be of wind-blown origin. 



Present Beach Features. 



The general sweep of Lady Robinson's Beach is broken 

 by several flat cuspate forms. The longest curve between 

 cusps extends from the mouth of Cook's River to President 

 Avenue, a distance of two and a-half miles. This portion 

 is exposed to the heavy waves pulsing through the heads. 

 Hence traced southwards the succeeding cusp is a mile 

 distant, while the remaining mile, or thereabouts, of beach 

 to Doll's Point is formed by a couple of small cuspate forms. 

 In the experience of the writer, the main outlines of these 

 large curves are preserved even during the heaviest gales. 

 A current generated by the wind and storm waves appears 

 to travel along the beach during heavy storms. 



Frequent features of the beach are the peculiar scalloped 

 forms (Figs. 2 and 7), of variable size and shape, to be seen 

 during periods of changeable weather. No consensus of 

 opinion as to their origin appears to exist among geologists 

 and geographers, and with a view of ascertaining the 



