SHORELINE STUDIES AT BOTANY BAY. 173 



Leueopogon lanceolatus, Sccevola suaveolens, and Acacia 

 longifolia var. sophora. Many of these, however, had been 

 removed from the sand dunes for purposes of park-making 

 prior to the 1912 storm, and the chief sand binders at that 

 time were Spinifex hirsutus, Leueopogon lanceolatus, 

 Xerotes longifolia (Liliacese), and Zoysia pungens. The 

 storm waves of 1912 undercut the long trailing stems of 

 the Spinifex, and exposed the long, broad, and deeply-set, 

 tufts of the roots of Xerotes in the sand cliff. Within a 

 year from July 1912, the wind had cut gullies or gutters 

 in the cliffs (Fig. 2 and Plate VI). The mouths of such 

 gullies or deep trenches opened out at the beach level and 

 the gutters of the trenches rose steeply to the crests of the 

 dunes in which they had been cut by the wind. The sand 

 moved in cutting the trenches may be seen piled behind 

 the heads of the trenches so formed where it was fixed 

 quickly by Cynodon dactylon, Zoysia pungens, and other 

 sand binders. The longer axes of these trenches point, in 

 the main, to the north-west or west-north-west, indicating 

 the southerly gales as their originators. 



The erosive action of the wind is thus seen to be decidedly 

 differential. As a rule the wind corroded an unprotected 

 sand area lying between a mass of Xerotes and a grass 

 patch. The wind removed the unbound sand while the 

 grass-covered patch of the Xerotes mass remained un- 

 scathed. Unless a great storm in the meantime, should 

 arise to modify the beach profiles profoundly, the later 

 history of the wind action would be to build the lower 

 terrace up to the tops of the dunes and to fill the gullies in 

 the dunes formed by the wind acting on the sandcliff front. 



Certain Observations on other Beaches around Sydney. 



As throwing light on the reason for the existence of the 

 present beach at Lady Robinson's, Botany Bay, it may be 

 advisable to mention certain features connected with other 



