SAXU-DUNES 25 



The waves having performed their task of bring- 

 ing the sand to the threshold, the tide takes up 

 the work of preparing the sand for the action of 

 the wind, the second transporting agent. The 

 waves maintain their dominion over the sand 

 till the highest spring tide is reached. After 

 that a margin is left along the flat beach, in- 

 creasing daily in width as the limit of high-water 

 mark recedes. Under the influence of the burn- 

 ing sun the surface moisture of this margin soon 

 evaporates, and when dry the sand is caught up 

 by the prevailing sea-breeze and blown in a per- 

 petual drift landwards. 



The density of this sand-cloud varies, of course, 

 with the velocity of the wind, but in a normal 

 summer breeze it is quite considerable, and can 

 be detected to a depth of about three feet from 

 the surface. The imagination, while it cannot 

 span the ages through which this drift has been 

 in progress nor grasp the extent of the mighty 

 monuments it has reared, yet is able to realize 

 what in fact has been taking place and w^hat is 

 now going on. 



Having escaped from the caverns of the deep, 

 the sand is not suffered to go very far in its 

 flight, for it is quickly arrested and imprisoned 

 by the vegetation of the land, which slowly yet 

 persistently reaches out ever farther and farther 



