GEOLOGY AND MINERAL RESOXJECES OF SIKHIM. 59 



Valleys to wbich glaciers come down, or whence these have but 

 recently retired, abound in small lakes or tarns which are dammed 

 in at the outlet by moraines. The Eidangcho lake, 3 miles north- 

 east of Gnatong, is the best instance I came across of a glacial lake 

 in a valley whence the glacier has recently retired. It is 1^ mile in 

 length, and its greatest breadth is ^ mile. 



The following hot springs are known in Sikhim : — 



1. Phut SacJm — On the east side of the Rungeet river, 2 miles 

 north-east of Rinchingpong monastery, situated amongst dark 

 coloured massive siliceous limestones. Hot fetid water bubbles up at 

 several spots. Temperature at one spring 100*4°F. The springs are 

 situated in the bed of the river which at the time I visited them 

 (March) was dry. These springs are referred to in Dr. Oldham's 

 "Thermal Springs of India" (Vol. XIX, pt. 21, p. 32) as 

 " Phugsachu." 



2. Ralonq Sachu — On the west bank of the Rungeet river, about 

 2 miles N.N.W. of Ralong monastery. Elevation about 3,100 feet. 

 Situated amongst finely laminated phyllites with abundance of vein 

 quartz, at a height of about 100 feet above the bed of the river. 

 Hot water flows out through fissures at several places. The tempera- 

 ture of the hottest spring close to where it comes out is I31°F. ; in a 

 reservoir constructed for bathing purposes, it is 1 18"4°F. The tempera- 

 ture of another spring close to where the water flows out is 114*8°; in 

 the reservoir it is lOTG". [The temperature of a stream close by was 

 found to be 53-6°.] A whitish deposit, which efPervesces strongly on 

 the application of hydrochloric acid, is formed at the mouths of the 

 springs. It is stained green in places with carbonate of copper, due, no 

 doubt, to the springs passing through cupriferous ores. It is very like- 

 ly these springs that are referred to in Dr. Oldham's list as " Puklaz 

 Sachu, about one day's journey from the monastery of Pemlong " 

 [op. cii, p. 32). Probably " Pemlong " is meant for Ralong. 



I heard of a hot spring about half a mile north of Ralong Sachu, 

 which I had no time to visit. 



3. Ycumtang — On the east bank of the Lachung river, half a 

 mile below Yeumtang. Though I passed the springs 1 could not get 

 at them owing to the bridge over the Lachung not having been 

 constructed at the time of my visit (May). They are described in 

 Dr. Oldham's list {op. cit., p. 32) : — " The discharge amounts to a few 

 gallons per minute ; the temperature at the source is 112^°, and in the 

 bath 106°. I'he water has a slightly saline taste ; it is colourless, but 

 emits bubbles of sulphuretted hydrogen gas, blackening silver."— - 

 [Hooker, Him. Journ., 1855, Vol. II, p. 126.) 



4. Momay. — " Hot springs burst from the ground near soma 

 granite rocks on its floor, about 16,000 feet above the sea, and only a 



