yiii] SAND DUNES 139 



and included, besides smaller holdings, some sixteen 

 farms. The disaster which buried the whole estate 

 beneath the sands came suddenly in the autumn of 

 1694. The sea had been encroaching extensively on 

 the land further to the westward, so that a large 

 expanse of sand was exposed at low water. It is 

 stated that a westerly gale carried immense quantities 

 of this sand over the fertile land, covering fields and 

 houses, burying the mansion-house itself, and even 

 diverting the course of the Findhorn river. Ever 

 since the Culbin Sands have been a vast shifting area. 

 If Marram Grass obtains a hold here or there, and 

 Dune-formation proceeds, it is again torn out by the 

 winds. A large part of the area remains as bare 

 Sand-hill, without a trace of vegetation upon it. 

 Here the surface sand is free to move with every 

 wind, and the form is constantly changing. The 

 effect of this is well shown at a point where a wood 

 of Scotch Firs had grown to maturity. The sand 

 advancing in a wreath some 40 feet high is gradually 

 enveloping the trees (Fig. 25). Elsewhere the sandy 

 pall is being removed again, and the dead stumps are 

 all that remains to show the destruction that has 

 been wrought (Fig. 26). The complete obliteration 

 of woods may be seen on even a larger scale else- 

 Avhere : for instance,:on the shores of Lake Michigan. 

 Such effects illustrate to the full the irresistible 

 advance of sand borne as individual grains by a wind 



