306 WAVES OF SAND AND SNOW 



being moreover in waves. Thus the circum- 

 stances of the flow and ebb of the spring tide over 

 the Waveridge Sand are such as to leave it nearly 

 smooth, although the currents are strong and the 

 waters deep. The circumstances to which atten- 

 tion should be chiefly drawn are the steep gradient 

 of the river, or estuary, and the presence of a side 

 channel into which the flood tide is diverted at 

 its commencement. 



The sand or shingle spits outside the estuaries 

 of the Mawdach, Findhorn, and South Esk prevent 

 the flood tide there from finding an alternative 

 channel. 



Lower down the estuary of the Severn, where 

 the Severn railway tunnel has been made, there 

 is a rocky shoal called English Stones, which com- 

 pels the incoming tide to stem the current of the 

 ebb and follow the principal channel under the 

 right bank. Thiis the reach of the Severn im- 

 mediately above the English Stones resembles the 

 estuaries of the Mawdach and South Esk. The 

 gradient of the channel in this part of the Severn 

 is also much less than at Severn Bridge. A little 

 higher up than English Stones is the shoal called 

 Dun Sands. Hearing that this, unlike the 

 Waveridge, was often in large waves, I went down 

 by boat next day, April 27th. I passed many 



