RIPPLE-MARK AND CURRENT-MARK 265 



distances from one cliff to another were irregular, 

 and although there was some approach to trans - 

 versality, yet in this respect, as in that of wave- 

 length, they did not satisfy the ideal of ripples or 

 waves. Two opposing influences seemed to be at 

 work, one trying to make transverse, the other 

 longitudinal cliffs. The surface of the sand was 

 compact and firm. 



In a deeper stream which makes its way through 

 the sandy beach at Mundesley in Norfolk, the 

 velocity where it issues from its culvert was about 

 the same as in the last case, viz., o'54 foot per 

 second, but the depth was greater, viz., 5 to 6 

 inches. In this stream the cliffs were at intervals 

 sufficiently regular to give the impression of ripples 

 or waves, and the average wave-length was 5*5 

 inches. There was a position to leeward of the 

 deepest places from which I could see the sand 

 departing in two directions, backwards towards the 

 foot of the preceding cliff and forwards towards 

 the brow of the next. The approach to each cliff 

 from the up-stream side was by a slope so gentle 

 as to be hardly perceptible. The surfaqe of the 

 stream was perfectly smooth and the water quite 

 clear. No sand could be seen in suspension except 

 a little which was churned up in the pool or trench 

 on the lee of each cliff. 



