310 WAVES OF SAND AND SNOW 



shore at 2.20 p.m. and watched from Beachley 

 Point. The sands were covered by 3.45 p.m., but 

 the English Stones were not covered until nearly 

 an hour later. A local pilot told me that the sands 

 were in an " eddy tide " during the commencement 

 of the flood, and that at high water on this day 

 there would be a depth on them of fully twenty 

 feet. Thu? the tide covers, and, I think, leaves 

 the sands gently , The situation, the depth of water, 

 and the low gradient of the channel are such that 

 there must be fairly strong currents on flood and 

 ebb running over the sands for a considerable time 

 when the water is deep. Thus they are thrown 

 into the larger kind of sand-waves which are not 

 obliterated when the water leaves them. 



The estuary of the River Dovey in North Wales 

 has extensive sandbanks, many of which are 

 covered with the larger kind of sand-waves. I 

 made observations here from May 31 to June 20, 

 1900. The tidal entrance clings to the north 

 shore of the valley, a long spit of sand and shingle 

 having grown out from the southern side. As in 

 the case of the estuaries at Barmouth and Mont- 

 rose, the spit formed by littoral drift has grown 

 from the side exposed to the longest stretch of 

 sea, and behind it the estuary has partially silted 

 up.: These estuaries may be classed as D,-shaped, 



