Yol. 56.] THE GEOLOGY OF GILGIT. 345 



Pakt II. — Topographical Description of the Rocks. 



I now pass on to describe the geology of the Gilgit area, as far as 

 the information at my disposal enables me to do so. I think that 

 it will conduce to clearness if I begin at the extreme southern 

 point in the Gilgit section, and thence work my way northward 

 to the high passes leading up into the Pamirs. (Map, p. 344.) 



(1) Nanga Parbat. 



This fine mountain rises to a height of 26,620 feet, and even at a 

 distance of 95 miles, my nearest approach to it, forms a magnificent 

 object. l My son is the first to give us any geological information 

 regarding this giant of the Hindu Kush. He ascended the Rupal 

 Nalah (ravine), which leads out of the Astor Valley and runs 

 along the southern face of Nanga Parbat. It was a little farther 

 up this nalah that the Alpine travellers, Mummery and Hastings, 

 lost their lives in 1896. My son went up the Tashing Glacier 

 and the Biji Glacier He writes: — 



' These two glaciers are fed directly and entirely from the highest 

 peaks of Nanga Parbat, the Biji Glacier being fed by the highest 

 peak itself. Both slope back to the foot of a bare sheer cliff falling 

 straight down from the very tops of the peaks. The debris on each 

 glacier is in each case all composed of one type of rock, as shown 

 by the specimens ; and as this debris comprises the detritus from 

 the very summits of the peaks, one can gather with almost absolute 

 certainty of what the peaks themselves are composed. There 

 is no reason why the specimens have not themselves come from the 

 central peaks ; and if so, they are specimens of rocks from a higher 

 elevation than any ever yet attained. I got them from a good way 

 up each glacier.' 



I have classed all four specimens as the acid variety of the Hatu 

 Pir Granite (see p. 342). These specimens are highly schistose, and 

 the Nanga Parbat rock may be called a granulite. It affords, I 

 think, good examples of a foliated structure superposed on granite 

 by pressure, fluxion, and shearing before final consolidation, and 

 complicated, in the case of these particular rocks, by some local 

 shearing after consolidation. 



The difference in the colour of the bands seen in these specimens 

 is not great, and appears to be due to twb causes : firstly, the segre- 

 gation of the biotite ; and secondly, the drawing-out of porphyritic 

 felspar-crystals into bands. In one specimen the porphyritic 

 felspars, blunted and elongated, can still be made out on an ex- 

 amination of the hand-specimen with a pocket-lens. In another 

 the process has gone further, and the rock has become schistose. 

 A third specimen has evidently suffered severely from pressure and 

 shearing. Not only have the felspar and quartz suffered in this 

 way, but leaves of red brown mica have been drawn out into strings 

 of imperfectly crystallized mineral matter resembling what I termed 



1 I was on a mountain oyer 9000 feet high. 



