1885.] SAND-PLAINS OF BELGIUM. 365 



of Denmark. On these the sand lies and increases more and 

 more. 



" To illustrate what tliere takes place, I must go back some way. 



" By great diifereuces in the condition and fixity of forms assumed 

 by the shore, there are places in which these become more prominent 

 and projecting than in others. Those advanced posts moderate, 

 in the intermediate stretches, the dash of the waves occasioned by 

 certain winds, and keep at a certain distance from the shore the 

 coast current, which usually follows a straight course. Both of 

 these results have as their consequences, that the sand and gravel 

 borne onwards upon the coast are deposited on or in front of the 

 bay formed by the said rocky projections ; and a low, flat, and 

 towards the land a somewhat indented and irregular shore is formed, 

 which is called the strand. This strand is generally pretty regular 

 sand 30° [fathoms?] broad, and on long stretches measuring some- 

 times more than two miles almost straight. 



" The movement into which the sea is cast by a storm, and which 

 shows itself on these shores in the dash of waves, has not only this 

 effect on them ; but, in proportion to the strength of the storm on the 

 deep, it takes also another, striking upon the shore perpendicularly, 

 and producing the so-called Grundivellen, or ground waves [ground 

 swell ?]. These Grundwdlcn shake and dig up the bottom of the 

 sea-basin, heave up the loosened material, and bear it onwards ; and 

 this they do not only with the fine sand, but also with the gravel 

 and even larger-sized materials which can be washed along ; the 

 Grundwdlcn with tlieir load breaking through the unresisting ocean- 

 current which has not yet been subjected to a similar upheaval, 

 and by means of these in their flow on the strand, deposit there 

 the material they have brought from the deep. 



"Every wave flowing over the strand contains also more or less 

 material taken from the deep sea-bed, and puts in motion along with 

 this the whole superficial portion of the .shore over which it passes, 

 bearing on with this the uppermost grains of sand. Again, as the 

 wave flows back, it takes also these grains of sand back with it. But 

 as this return of the wave is occasioned only by its own gravity, and 

 works in accordance with the laws of gravity operating on it, and 

 the sand being two and a half times tlie specific gravity of water, a 

 portion of it remains behind the receding wave, and near the spot 

 to which it had been borne ; and the remainder is anew thrown 

 upon the strand by the next return of the wave, but in such a way 

 that a portion must return to the deep sea whence it was brought. 



" In every way the waves tend to bear the sand of the strand 

 outwards, and whenever by a storm the water along the shore is 

 raised to any considerable height above its usual level, the transport 



