196 GRIESBACH: GEOLOGY OF THE CENTRAL HIMALAYAS. 



viewed from between the village of Namgeah, and the south ascent 

 of the Shipki valley. The felspar contained in this granite is 

 represented by white albite, and as accessory minerals I found beryl 

 and kyanite freely disseminated throughout the rock. As far as 

 I could ascertain, this same granite, often inclosing masses of altered 

 sedimentary rocks of greater or lesser extent, forms the hills on both 

 sides of the Sutlej valley near Shipki, extending far to the south 

 and north. Further eastwards on Tibetan ground the sediment- 

 ary series follows in normal order. 



To follow up the intricate and often indistinct boundary of the 

 granite intrusions with the neighbouring strata, would have required 

 a great deal more time than I could devote to the entire work of 

 Himalayan exploration, and I had therefore to content myself with 

 establishing the fact that such granite intrusions do exist near the 

 base of the haimantas, and not only obscure the latter, but penetrat- 

 ing them and convert the shales and phyllites of this system into 

 a more or less metamorphic series. I found it therefore impossible 

 to do more than indicate on the map, partly diagramatically, how 

 this boundary runs, and further I found it more convenient to distin- 

 guish on the map No. 2 with one colour (pink), not only granite, 

 but also the various crystalline rocks which make up the main ranges 

 of the higher Himalayas, amongst which a grey gneiss with horn- 

 blende is the most prominent ("Central gneiss" of Stoliczka) rock. 



The Nilang sections. 

 The Bhagirathi river exposes a good section through the crystal- 

 line rocks of the Central Himalayas of Tihri Garhwdl. South-west 

 of Nilang, practically the only rock traversed is granite, and granitic 

 Granite south-west of gneiss with isolated masses of schists. The 

 ng * dip of the latter and the granitic gneiss, where 



bedding is visible, is almost uniformly to north-east, varying from 

 w . . 45 to 50 . Between Batwari and Jalah, the 



Gneiss of Batwari. 



prevailing rock is a grey gneiss in thick beds, 

 in which occasionally beds of micaceous and chloritic schists are 



( >96 ) 



