172 



E. C. ANDREWS. 



the varying degrees of hardness and strength in the material 

 attacked, and that it must tend to carve ravines and valleys 

 in the softer rocks and leave the harder masses as residuals. 

 Furthermore it seems improbable that a wind should blow- 

 steadily over great regions with constant direction and 

 uniform strength during a geological period so as to 

 accomplish peneplanation. 



A B G — Trenches cut by wind. 

 Fig. 2. — Diagram of central portion of Lady Robinson's Beach in 1915. 

 The V-shaped trenches have been cut by wind in the subdued storm profiles 

 of the 1912 storm. 



The terrace beneath the subdued cliff is a growth since July 1912. 



No sooner had the cliff been cut in the sand dunes of 

 Lady Robinson's Beach by the storm waves of July 1912, 

 than the unstable profile was subdued rapidly in great 

 measure. Children in hundreds, attracted by the unac- 

 customed and enticing nature of the sand cliff, tumbled, 

 cascaded, and slid, down the face until the slope was 

 reduced rapidly to an angle less than 50° to the horizontal. 

 The wind also attacked it vigorously, especially on the cliff 

 edge. Many sand binders had fixed the dunes in great 

 measure previously, for example, Spinifex hirsutus,Leptos~ 

 permun Icevigatum, Zoysia pungens, Correct alba, Mes- 

 embryanthemum equilaterale,Xerotes longifolia, Rhacfodia 

 Billiardieri, Imperata arundlnacea, Cynodon dactylon, 



