Vol. 56.] THE GEOLOGY OE GILGIT. 353 



west of that above described, high above the zone of cultivation in 

 the Hunza Valley. The accompanying diagrammatic sketch (fig. 2, 

 p. 352), kindly made for me by Capt. Eoberts, shows the mode of 

 occurrence of the Altit Beds. The true dip is higher than that 

 shown in the sketch. 



' On the march from Altit to Gulmit,' writes Capt. Eoberts, ' one 

 goes east along the limestone-series, then turns north across the 

 strike and on to the gneiss-series. The hills passed on the right 

 bank are covered with numerous pinnacles and cathedral-rocks, 

 of which the Hunza Feathers 1 are a part. There are some six 

 hot springs (temperature about 90°) issuing from below, or among, 

 the lower beds of the stinkstone in a distance of some 16 miles. 

 This water does not smell of sulphuretted hydrogen, but seems to 

 contain alkaline salts, as in one spring, where it is more abundant 

 than in the others, the incrustation deposited is used by the country 

 jDeople to wash their clothes with.' The sample sent me consisted 

 of magnesium sulphate (Epsom salt). 



I have made a microscopical examination of the schists inter- 

 calated with the stinkstones between Altit and Ata-abad. 

 They are mica-schists composed of quartz, felspar, biotite, mag- 

 netite, garnet, a little sphene, and epidote. In one specimen the 

 felspar is comparatively fresh, and, judging by the extinction- 

 angles, is in part andesine and in part oligoclase. In the second 

 specimen the felspar is so altered as to be almost unrecognizable, 

 and the garnets are flattened and drawn out in the direction of the 

 schistosity. The quartz still contains gaseous and liquid cavities with 

 bubbles. The first specimen contains, in addition to other minerals, 

 hornblende and calcite. 



The two specimens just described represent, I think, sheared 

 granites of the Baltit Hornblende-Granite type. They might 

 belong to a very early eruption, or to an early phase of the Baltit 

 Granite- eruption itself. The Baltit rock is the oldest granite in the 

 district, and it was, as we shall see below, undoubtedly erupted into 

 the stinkstones. These particular sills were, I should imagine, in- 

 truded into the stinkstones during the earliest phase of the eruption. 



I do not regard the alternative hypothesis, that these schists 

 represent sheared arkoses, as probable. It does not seem at all 

 likely that fragments of granite unmixed with other detritus were 

 carried out to sea, and deposited at a spot where very pure limestones 

 were being laid down. 



I now pass on to allude to the granites that invaded the 

 stinkstones at a later phase of the eruption, presumably 

 after the crumpling up of the limestone-beds, and contributed so 

 largely to their metamorphism. ' Another interesting feature of this 

 series ' [the stinkstones], Capt. Eoberts writes, * is that it has been 

 pierced by dykes of granite that pass through the limestone-beds and 

 spread themselves in innumerable veins and dykes in the series of 

 rocks lying above the limestones.' 



The first to be mentioned is the Baltit Hornblende-Granite. It 



1 See Conway's 'Climbing & Exploration in the Karakoram Himalayas' 



