SNOW-WAVES AND SNOW-RIPPLES 175 



Fig. 6, p. 114). The concentration, in the centre 

 of the eddies from the right and left hand, however, 

 sweeps the snow back more rapidly there, so that 

 the line becomes crescentic with the extremities 

 advanced to leeward. The plan of the crescentic 

 mound is not always the same in either material. 

 In some cases the cusps are short compared to the 

 fore and aft length of main mass, and sometimes 

 long. In the latter case the plan somewhat re- 

 sembled that of the elongated horseshoe -shaped 

 bank of snow formed around clumps of bushes or 

 around houses on the prairie. Owing, however, to 

 the retreat of the mound the lines of the weather 

 end remain finer, both in plan and profile, than 



Fig. 26 



HolIbwCLCtby wind. From left, around alieap of manure 

 en a. field , from a. photograph. 



those of a bank which occupies the eddy-space 

 of a fixed obstruction, but I think the whole space 

 occupied by the mound itself and the eddying wind 

 to leeward has generally, perhaps always, the bluff 

 head and fine tail arrangement, so that if it were 



8 



