GEOLOGY AND MINERAL RESOURCES OP SIKHIM. 71 



ores in slaty shales with segregated quartz. The ore-bearing band was 

 found only 6 inches in thickness at one place. The ore is found in 

 traces on both sides of the river. The dip here is NW about 65°. 



16. RatJioJthani. — Close to the village of Chakang, The mines 

 here are the oldest in Sikhim, and were in working at the time of 

 Mr. Mallet's survey of the Darjeeling district.* The ore (copper 

 pyrites) occurs in slaty shales as well as in lenticular bands of segre- 

 gated quartz, especially in the latter. Mr. Mallet found 91 per cent, 

 of copper in a carefully selected average sample; it is not, therefore, 

 nearly so rich as that of Pachikhani. The ore is confined to the east 

 side of a ravine which apparently marks the position of a fault: 

 east of it the strata are inclined south-east to north-north-east, whereas 

 west of it the strata exhibit the normal dip of these parts, viz., north- 

 west. The workings extend for about 100 yards on the east side of 

 the strike of the strata. The main drifts run parallel to the bedding ; 

 but meandering passages across it in all directions also exist. The ore 

 here appears to occur in segregated veins parallel to bedding, and there 

 did not appear to be any indication of a true__ lode. Still the oriferout 

 beds may, I think, be advantageously followed deeper down. The 

 difficulty of drainage has led to their abandonment ; and at present 

 the miners burrow here and there on a small scale. 



Masses of quartz rock containing copper pyrites are found in 

 the bed of the Ratho, a short distance below the mine. An average 

 sample yielded on analysis 6'38 per cent, of copper. 



3. — Summary and concluding observations. 



The following is a summary of the copper localities mentioned 

 above : — 



(4). — In the Dalings. 



(1) Mines now worked ... ... Pachikhani, Rathokhani 



(on a very small scale). 



(2) Mines recently abandoned ... Old Pachikhani, Bhotang. 

 Mines abandoned and wholly choked up Tukkhani. 



Localities where trial openings have Dajong, Rinchinpong, 



been made and abandoned. Temi. 



Localities not yet tried ... ... Rhenock, Bam, Mongbru, 



Barmiak, Namphak, Mik. 



{B). — In the Gneissic rocks. 

 Localities not yet tried ... Lindok, Lingui, Ronglichu. 



The Nepalese miners have a very keen eye for copper ores ; and 

 the localities where they have been mining or rather burrowing — 



* Op. cie., p. 75. 



