96 BEACH GRASS 



for the winds are then the strongest and, as a 

 rule, the snow and sand blow about together, 

 forming gray drifts of mingled sand and snow. 

 In the northern blasts, the conical dunes smoke at 

 the top like wigwams, the cirque dunes are 

 rapidly undercut and build up to leeward and 

 the desert dunes deposit their load of snow and 

 sand on the steep southern side. Often the snow 

 and sand are segregated and form alternate 

 layers, wavy lines and concentric circles, alter- 

 nately gray and white, sometimes in patterns of 

 considerable beauty. 



On the leeward side of a dune, the southern 

 side in winter, where the sweep from the north 

 is unobstructed by vegetation, masses of snow 

 sometimes accumulate and are buried in successive 

 layers of sand. One of these, which I called 

 glacier dune, I described in "Sand Dunes and 

 Salt Marshes" and told of finding snow there 

 throughout the month of May. One may easily 

 recognize these caches of snow as the spring comes 

 on by the dampness and therefore darkness of the 

 sand over them, but especially by the cracks in 

 the sand. As the snow m.elts below, the sand 



