1862.] Notes of a trip from Simla to the Spiti Valley. 515 



to Jake Chomoriri, which a restoration of a more humid climate, 

 such as formerly existed, would very speedily once more obliterate. 



How far the theory which I have formed regarding lake Chomo- 

 riri is applicable to any of the other lakes of Ladak, I cannot say ; 

 but a glance at the map suggests such a possibility, as some of them 

 seem to be, what I take this lake to be, a river valley dammed up, in 

 consequence of changed climatal condition and a diminished rain-fall. 

 In two important points, this lake differs from those which at present 

 constitute the remnants of the old lake system of Ladak. 



1st, — It nowhere affords any indication of having ever obtained 

 larger dimensions than it at present occupies. 



2nd. — Its waters, though they abound in animalculse (entomostraca), 

 do not yield a single mollusk ; nor are any shells to be found in the 

 sand and shingle along its banks, which is merely such an accumula- 

 tion (often a thick one) as the mountain torrents pouring clown from 

 the neighbouring hills have spread out along its shore. 



The diagram in the annexed plate will help to explain better 

 than description how a river valley has been converted into a lake, 

 and the peculiar configuration of the ground which has aided such 

 a result. By this sketch it will be seen that the valley in which 

 Chomoriri lake is situated, is, not far above where it opens into the 

 valley of the Para river, much narrowed and constricted by hills 

 which approach within less than a mile of each other, the valley ex- 

 panding to a breadth of several miles higher up. Not far above this 

 narrow part of the valley a large stream, which when I crossed it 

 had two channels with water rising above the knees, enters and 

 turning round abruptly runs into the Para river. This large stream 

 sweeps down a large quantity of boulders and gravel which it spreads 

 over the valley in the form of a huge bank, on the summit of which it 

 scores ever changing channels, and which entirely shuts out all view 

 of the lake to any person ascending from the Para river, till he has 

 attained its summit and crossed the stream which has caused the 

 obstruction. The rise over this bar from the Para river seemed much 

 steeper than the descent towards the lake, which it will be seen is 

 nothing more than the drainage of the main valley dammed up by a 

 barrier raised by a powerful affluent stream, favoured somewhat by the 

 configuration of the ground, but also by the inability of the recipient 

 stream to remove that shingle swept into it by one of its feeders and 



3x2 



