156 OLDHAM: SANDHILLS OF CLIFTON NEAR KARACHI. 



of this method of protection. If, however, this method of fixing 

 the sand were adopted at Clifton, the spacing would have to be closer, 

 at any rate in the case of the sandhills near the road, where it is neces- 

 sary not only to fix the sand already accumulated, but to catch the 

 drifting sand which would otherwise form fresh sandhills further on. 



The material used in Germany is usually pine twigs, from which the 

 thinner parts have been cut away, but reeds are often used. These 

 have not the strength of wood, but are used where it is only desired to 

 fix the sand for a sufficient time to permit of a pine plantation establish- 

 ing itself. They are cheaper than brushwood and have the advantage 

 that, if sand accumulates, they are easily drawn up, and the fence re- 

 established ; owing to their greater weakness they must, however, be 

 more closely planted than twigs. Plate III, fig. 1, shows fencing of 

 this character formed of reeds. 



The method of fixing loose sands has been described in some 

 detail, as it may have a more extended application than merely to the 

 Clifton sandhills, but it must be regarded merely as a means of fixing 

 existing loose sand, not of preventing its accumulation; and even in 

 this aspect it is, or should be, merely a temporary measure, to be 

 followed as soon as possible by the planting of local grasses or other 

 vegetation which will serve to permanently bind the sand. 



The other object, of preventing the accession of sand, is attained 

 by the building up of a continuous dam along the shore. The process 

 is illustrated on Plate XII, taken from the same book as has been 

 freely quoted above. The first step is the building of two parallel 

 fences, of 28 and 36 inches in height, and a couple of yards apart. 

 These fences are of the type represented in fig. 11, without the 

 supporting framework if the material used is strong enough to enable 

 it to be dispensed with. When sand has accumulated over these, 

 another pair of fences is erected on the sand ridges, and when these 

 have been buried the ridge is high enough and fixed enough to allow 

 of grass being established on it. The grass having established itself, 

 catches the drifting sand, and by degrees a broad sand ridge, with 

 gently sloping sides, is built up. It would be possible to build up a 

 sand ridge of this soit on the Clifton shore, which would prevent the 

 ( 24 ) 



