90 WAVES OF SAND AND SNOW 



August day in dry and breezy weather the wind 

 had covered the loose sand of the beach with 

 ripples 3 inches in length, which extended laterally 

 as much as 27 feet without a break. They 

 had, however, a feature not seen in the ripples of 

 the quartz sand near Bournemouth, each ridge 

 having notches at intervals, where the straight 

 front was interrupted for a space of about 

 3" 5 inches, the apex of the recess being rather 

 more than 1*5 inches behind the general frontage. 

 The trough was deeper in the notches than else- 

 where and the sand coarser in grain. The crest 

 was not, however, any higher at these places. The 

 notches occurred at somewhat irregular intervals of 

 about I 2 inches on each ridge, but were repeated 

 exactly from one ridge to another, being arranged 

 in lines parallel to the wind. Apparently, there- 

 fore, any pit formed in the trough tends to be 

 deepened, but there is no compensating formation 

 of peaks on the crests. The stronger eddy pumps 

 up more sand from the trough, but apparently the 

 flat particles of the shell-sand cannot withstand 

 the ploughing-off action of the direct current. 



