1873.] 



DREW — UPPER-INDUS BASIN. 



449 



vines of a uniform character, project fans that have coalesced together, 

 and now make a continuous spread of fan-deposits nearly two miles 

 in width, extending along the foot of the mountains for a distance of 

 30 miles. The fans, although touching, are still distinguishable one 

 from another ; the line of junction in the hollow between any two of 

 them is always marked, as well as the ending of the fan against the 

 main- stream alluvium. In fig. 7 is depicted a somewhat similar 



Fig. 7. — Fans united (five miles south of Pamzalan, Changchenmo, 



Ladakh). 



succession of fans which have met. These are of a greater slope and 

 of a less area ; they occur by the side of a feeder of the Changchenmo 

 river, at a height of between 15,000 and 16,000 feet. 



In Ladakh it is generally upon alluvial fans that cultivated ground 

 occurs. In that country nothing can be grown without irrigation ; 

 and the places are few where the waters of the main rivers, such as 

 the Indus and the Shayok, can be made available for it. The water 

 of the side streams is that which is made use of ; and this is led, for 

 these purposes, over the fan-stuff deposited by itself. Still, of the 

 whole fan-area, a very small proportion is tilled. Going along such 

 a space as was above described (opposite to Leh) we may find every 

 three or four miles a village or a hamlet with a cultivated area of 

 fifty to a hundred acres ; and the rest will be dry, bare, stony ground. 

 The reason varies for different cases. Sometimes it is that, from the 

 occurrence of ravines such as will be described further on, it is dif- 

 ficult to bring the water on to the surface of the fans ; sometimes 

 the quantity of water in the ravine is itself limited, and in summer 

 lessens to far below what would be necessary to irrigate any large 

 proportion of the area of the fan ; sometimes, again, the material is 

 such as to make an intractable surface. 



Another combination of fans is when, projecting from ravines on 

 opposite sides of a large stream, they meet, or nearly meet, and the 

 river flows confined between them. 



In narrow valleys, a fan from one side, even, can reach across the 



