GEOLOGY AND JIIXEKAL RESOURCES OF SIKHIM. fi 1 



underlie the gneiss, the dip of both being north-eastern. So do they 

 also at the western boundary, which passes by Pemiongchi, the first 

 monastery in Sikhim, the dij) there being north-western. At the 

 southern boundary, which is in the Darjeeling district, and which 

 appears to be faulted, the dips of both the groups are southern. 

 Wherever the junction between the two groups is observed, the 

 Dalings appear to underlie the gneiss ; and the fact that the former 

 pass into mica schists at places near the junction makes it appear as 

 if there was a passage from the one to the other group. Indeed, 

 Mr. Mallett considered the gneiss as more recent than the Dalings.* 

 But the former being presumably the older rock, it would be prefer- 

 able to find some other explanation for the apparent underlie of the 

 Dalings. 



The fact that near the junction everywhere the gneiss dips in 

 the same direction as the Dalings, shows that the former was largely 

 affected by the disturbing forces which tilted up the latter. 



2. — The Dalings. 



This name was given by Mr. Mallet to a group of submetamor- 

 phic rocks after a place called Daling in the Darjeeling district. 

 Phyllites form the predominant rocks in this groujD. At the bound- 

 ary between it and the gneissose rocks, they pass into silvery mica 

 schists ; in fact, in this position the passage is sometimes so gradual, 

 that it is difficult to say where the one group begins and the other 

 ends. Dark clay slates with thick quartzite bands prevail near 

 Chakang, Pachikhani (south of Pakyang), &c.; the workable copper 

 ores invariably occur amongst these rocks. Gritstone is sometimes 

 met with as just south of Namchi; but conglomerate never. Impure 

 siliceous limestone is found north-east and north-west of Namchi, and 

 highly carbonaceous shales occur in the Mangpur jhora just south of 

 Namchi, by the Rungeet east of Chakang, and by the Rummam near 

 Gok (south of Chakang). 



Igneous rocks are rare. A rather thick band of gneissose 

 granite was met with between Murtam and Ramtpek which continues 

 for some distance northward as well as southward, forming the ser- 

 rated peaks D : 5 and Maphila. It is probably of intrusive origin. 

 An unquestionably intrusive dioritic-looking rock was encountered 

 penetrating through slates by the road between Song and Tikobu. 



The Sikhim Dalings occur somewhat in the form of a dome- 

 shaped anticlinal. On the south side the dip is southern ; east of the 

 Rungeet it is chiefly E.N.E.; west of that river the inclination is 



* " Memoirs, Geological Survey of India," Vol. XI, pt. 1, p. 42. 



