FIXING OF LOOSE AND MOBILE SANDS. 229 



enough never to be drifted abont by the wind or they may be BO 

 fine that they form perpetually moving waves and hills. 



ARTICLE 1. 

 SANDS UNINFLUENCED BY WINDS. 



Instances of such sands we have along nearly all our low coasts 

 and in the loose deposits left by wandering rivers in northern 

 India. They require fixing only in the sense that in most cases 

 a little cohesion would increase their hygroscopicity and give the 

 necessary foothold to trees grown on them. Where a perennial 

 supply of water is close to the surface, as on those low coasts and 

 in many of the river deposits referred to, sowings of woody species 

 may take place at once without any special preliminary preparation, 

 more particularly as numerous grasses and species of Carex with 

 long creeping rhizomes and rooting stems come up spontaneously 

 therein and help to bind together the loose particles to a certain 

 extent. And indeed, even if such plants were absent, they could, 

 if required, be introduced there without any difficulty. 



ARTICLE 2. 



DRIFTING SANDS. 



It is evident that before any forest operations can be attempted 

 in such areas, the drifting about of the sand must once for all be 

 stopped. Experience of such work in India is limited to the ad- 

 vanced little State of Jeypur. We can, therefore, do little more 

 than place before the student certain general ideas, which may be 

 of some practical utility in suggesting special methods when any 

 occasion or necessity for fixing drifting sands presents itself. 



We will consider separately the two cases of drifting sands on 

 the sea coast (coast dunes) and of those in the interior (inland 

 dunes). 



We have not, for obvious reasons, included here the case of 

 invasive sands brought down in consequence of the denudation of 

 hill ranges at the upper end of a river basin, a striking example 

 of which we have in the hills behind Hoshiarpur in the Punjab. 

 In that case the evil can be stopped only by attacking it at its 

 source, viz., by reboising the hills in question or by putting a stop 

 to their disforestation and carefully conserving the forest growth on 

 them. The consolidation of unstable slopes is treated of in the next 

 Article. 



1. Coast Dunes. 



On many low beaches every high tide leaves behind it quantities 

 of very fine sand, which, drying, is continually drifted inland by 



