462 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 28, 



At one part I reckoned the river to be 80 yards wide, while 

 flowing at the rate of 2| miles an hour • elsewhere it had divided and 

 flowed in more than one channel. Near the end of our distance the 

 width of the flat had increased to 4 miles ; and just below this the 

 river-channel was between 200 and 300 yards across, but with this 

 width was shallow, as it was here fordable at a depth not over 

 3 feet. The surface of the alluvium is thinly covered with grass. 



The alluvial substance is for the most part clay — sometimes a 

 dark-coloured clay and sometimes drab clay — while at some parts not 

 lately washed by the river it was sandy. I was there in August of 

 1869, and for a time the water of the river was perfectly clear ; but 

 one day we found it had become muddy ; this had no doubt been 

 caused by an increased melting of the snow in the still higher parts 

 of the river-basin, within the Chinese territory. A very little more 

 increase of volume would have brought the water over the banks, 

 and caused a deposit of silt and an addition to the alluvium. For 

 this reason I do not see the necessity of supposing that this 

 alluvial flat was deposited in a lake ; it does not differ from the 

 river-alluviums of our own country, which are made by the overflow 

 of the water at flood times. The flat, though level to the eye, 

 really slopes with the valley at a gradient corresponding to the fall 

 ef the water. At the same time I think it very probable that the 

 low slope of the river and its alluvium was due to obstacles that 

 came across the valley just below, which first probably caused a 

 lake, and then a rearrangement of the bed to its present angle. 



Along that flat down to the first villages that occur in the valley, 

 called JSTimu and Mad, one does not see alluvium at a higher level 

 than that recently formed. Below, at the place called Maiya, is a 

 section showing beds of felspathic and micaceous sand and light- 

 drab clay, the deposit of the river, at a height of 30 feet above the 

 stream. From this point onwards, for some 60 miles, the Indus 

 flows through the narrow rocky region called " Rong." Here I 

 have not followed it*. 



* I will put down here in a note a short account of certain deposits in and 

 near this part which I have not been able satisfactorily to account for or to 

 classify. Near that uppermost flat of the Indus, in the tract called Kokzhung, 

 where "sand-hills" is marked on the eight-miles-to-an-inch map of the G-. T. 

 Survey, is a line of low hills or mounds connected, occupying on the right bank 

 of the river, between its alluvium and the fans from the mountains, a space 

 about 4 miles in length and 300 to 400 yards in width, and rising to a height 

 of 300 or 400 feet. Again, 3 or 4 miles further to the south-west is an isolated 

 mound, a few hundred yards long, about 100 yards wide, and 60 feet high, of 

 like character. There is no flat top or terrace. The surface is undulating or, 

 rather, moundy. The substance of the hills is mixed : there is small granite, 

 gravel, and even sand ; there are stones of shale, chert, sandstone, and green- 

 stone ; and there are larger boulders of granite : for the most part it is either 

 angular or only partly rounded. I should have no difficulty in considering the 

 hills to be merely an old moraine left by some glacier, but that I observed at 

 one part of them, near the north-west end, strata of clay, sand, and pebbles, 

 dipping towards the hills (north-east) at an angle of 40°. I estimated a 

 thickness of 60 to 80 feet of these beds ; and there may have been more. 



Again, behind the village of Chushal, in the basin of the Pangkong Lake, 

 are mounds 200 feet and more high, which are composed partly of irre- 



