CHESIL BEACH. 3 



act, are due to the preponderance of westerly winds. I have 

 already stated that it is to the wind-wave, rather than to tidal 

 currents, that we must look for the main part of beach action ; 

 at least, above low water mark. Now, does any inhabitant of 

 the British Isles doubt the preponderance of westerly winds on 

 an average throughout the year .^ Where groynes are numerous 

 and the distance to be travelled is not far, the effect of gales 

 from alternate quarters may be well studied, as, for instance, on 

 the Sussex coast, where the wind-wave for the time being prevail- 

 ing heads up the shingle against the opposite groyne. But in the 

 case we now have under consideration there is only one gigantic 

 groyne — viz., Portland itself, which also protects the shingle of 

 the Chesil Beach from the effects of easterly gales. Thus not 

 only is there a preponderance of the wind-wave from the west, 

 but the easterly gales are deprived of a portion of their driving 

 power for some distance from the Chesilton end owing to the 

 shape of the West Bay. 



No wonder, then, that the shingle accumulates against 

 Portland, the biggest groyne in the Channel. Still, you will 

 say, the mere fact of accumulation does not seem to account for 

 the marked increase, or grading, in the size of the stones. On 

 this point there may be some slight room for difference of 

 opinion yet. For instance. Sir John Coode, if I remember 

 rightly, argued that powerful wind-waves moved big stones 

 more than little ones. I may, however, be doing him injustice 

 in this respect. At any rate, that author always based his 

 arguments on the eastward movement of the beach material. 

 It remained for Dr. Vaughan Cornish to point out that the 

 grading was effected by the preponderance of the wind-wave 

 from the westward. The same cause which heaps up the 

 shingle at the Portland end also serves to pick it over, because 

 not only is there a balance in favour of west winds, but they are 

 also the most violent. We may grumble at the persistence of 

 the east wind in spring, yet its effects are slight, compared with 

 those of such a hurricane as the one five years ago, which blew 

 from the west. Now, it is just these hurricanes which enable 



