114 



is carried into the lake in the backwash of the waves, thus 

 leaving a mound of sand, thoroughly permeated with J uncus 

 rhizomes and usually having a coat of exposed rhizomes, which 

 become dry under the desiccating action of the wind and sun. 



At first the relic dunes are elliptical in shape, with their major 

 axis parallel with the shore line. By washing away the ends, 

 however, succeeding storms reduce them to an approximately 

 circular outline. In this form they may endure for a couple 

 or more years, depending upon the violence of the storms. 



The relic dune itself is a mound of sand about 2 meters 

 high and about 2.5 meters broad. At the top is a very dense 

 growth of Jiiiiciis balticHS littoralis, whose rhizomes thoroughly 

 permeate the dune. At the outside the exposed rhizomes, which 

 usually form a rather dense matwork, protect the dune from 

 both the desiccating and mechanical effects of the wind. From 

 the attack of the waves the rhizomes are of relatively smaller 

 value. The sides of the dunes are cut out in grooves, especial- 

 ly near the bottom where the wind and wave action is more 

 pronounced. A few secondary species occur on the cap, such 

 as Sporobolus cryptandnis, Coniiis stolonifcra, Calamovilfa 

 longifolia, and Salsola kali toiui folia, but the number of in- 

 dividuals is so small that they are of relatively no importance 



The Juniperus conununis deprcssa relic dune, of which ar 

 the present writing there is only one in the area, is a i>oorly 

 developed dune near the limit of wave action. The roots of this 

 plant have not the sand binding power that those of the Jimciis 

 have. Consequently any exposed sand would be blown away. 

 As the sand is removed by blowing or otherwise, the outer- 

 most branches of the juniper sink down and cover the sides 

 of the mound with vegetation which protects it in quite a fair 

 measure from much further action by the wind. Toward the 

 west or landward side the prevailing westerly winds keep pil- 

 ing up sand faster than the juniper can cover it up. Within the 

 next few years, if the present rate of erosion continues, there will 

 be seven or eight more relic dunes of both species of juniper, at 

 which time a better understanding of this class of relic dunes 

 rvill be possible. 



