8 MALLET: GEOLOGY OF DARJILING AND WESTERN DUARS. 



delta formed a part of the lake, and from what I have seen of the 

 transporting- power of the hill streams, I can well believe that the 

 present delta could have been formed in this time, especially as the 

 upper Ramthi flows entirely through brittle, easily broken up, slates. 

 The first lateral torrent above the lake on the west side contributes 

 an immense amount of debris from a naked precipice at its source. 

 Of course the commencement of the delta must have been synchronous 

 with the earliest existence of the lake, and although the Lepchas' account 

 may not be strictly true, the delta is certainly not of high antiquity. 



As for the mode of formation of this sheet of water, its recent 

 origin puts glacial action in any form out of count, even if the low 

 altitude, about 1,000 feet above the sea, does not do so. The stream for 

 a mile below the exit has a much greater fall (400 feet) than either further 

 down, or above, the lake ; and the bed is there filled with huge blocks of 

 Tertiary sandstone, amongst and under which the water flows. I have 

 nowhere, except here and below the Dohir Tal, — a similar but much 

 smaller lakelet, about half a mile to the eastward,— seen an accumulation 

 of this kind ; and it seems most probable that both lakes and blocks are 

 due to one or more landslips from the hills above, which have dammed 

 up the original bed of the stream. The blocks are all of Tertiary sand- 

 stone, and hence cannot have been washed down stream, as the rocks 

 above the lake are Damudas and slates. For the same reason, besides 

 those given above, they cannot be the remains of a moraine. 



Hot springs are known to exist in Independent Sikkim, but the only 



indication of such in the Darjiling district that I 



could hear of, was at the Mangphu copper mines 



on the Tista. About 600 feet above the river there are two or three 



small clefts in the slate, the air in which feels warm and moist to the 



hand when inserted, and l clouds ' are said to issue from them morning 



and evening, when no doubt the vapour is condensed by the coldness of 



the air. The clefts are incrusted here and there with sulphate of copper 



( § ) 



