368 LIEUT.-GEN. C. A. MCMAHON ON [May I9OO, 



EXPLANATION OF PLATE XXIII. 



[Illustrations of some phases of the partial resolution of quartz and felspar 

 by liquid residual quartz. All the illustrations are reproductions of photographs 

 of slices seen under crossed nicols, made from specimens of Gilgit granite.] 



Fig. 1. The amoeboid structure of residual quartz. (See p. 342.) 



2. Tessellated residual quartz eating into crystals of felspar. (See pp. 366, 



367.) 



3. Tessellated residual quartz eating into a large quartz of first generation. 



The lower dark portion of the figure is felspar. (See pp. 366, 367.) 



4. Residual quartz eating into felspar-crystals. The dark portions on the 



right and on the upper left hand of the figure are allotriomorphic 

 felspars corroded by the quartz. The fingers projecting from the 

 hand-shaped quartz on the upper right hand illustrate the tendency 

 of the corroding quartz to avail itself of the structural planes of the 

 felspar. (See pp. 342, 366.) 



5. Residual quartz eating into a felspar-crystal, and appearing in its interior 



as blebs and irregularly-shaped patches. (See p. 366.) 



6. Residual quartz passing into granophyre. The dark portions of the 



figure are felspar ; the light portions, quartz. The oval and pear- 

 shaped pendants near the centre of the figure exhibit granophyric 

 structure. This is quite distinct when examined under a micro- 

 scope with high powers : a 1-inch objective was used for the 

 illustration. The circular white spot at the lower end of the figure 

 is a bleb of quartz in the felspar. (See pp. 366, 367.) 



Discussion. 



Col. Godwin-Austen said that in 1860 he was deputed by Capt. T. 

 G. Montgomerie, R.E., in charge of the Kashmir Survey party, to 

 survey Baltistan with the plane-table on the4-mile-to-the-inch scale. 

 In that year and the following he completed the area partly shown 

 on the map exhibited, bounded on the west by the longitude of 75°, 

 and extending from the northern edge of the Deosai Plateau to the 

 ranges and great glaciers at the edge of the Shigar River, his limit 

 on the north-west being the Hispar Glacier ; thence eastward along 

 the Mustagh Range, the Baltoro Glacier (until then unknown), 

 the Masherbrum Range, and the Hushe Valley, to the Shay ok River 

 and the Indus. While this work was in progress, he had great oppor- 

 tunities for observation of the geology, and he laid down the 

 boundaries of the stratified series. He had always hoped to get 

 back to that part of the world, and to continue the survey to the 

 westward ; but in 1862, owing to the illness of another officer 

 of the Kashmir party, he was sent to survey the Chang-Chingmo 

 and Pangkong Lake, far to the east of Ladak. The Author had 

 given him undue credit for having penetrated farther than he did. 

 It was the Nushik La, not the Shimshal, to which he had told 

 him that he had penetrated, the pass crossing over to the Hispar 

 Glacier, which was the nearest point that he reached towards 

 Hunza Nagar. Forty years ago all the country to the west was 

 unknown and unsafe : no European officer had yet been in Gilgit. 

 The most powerful chief in Hunza was Gor Rahman, a name dreaded 

 by his neighbours far and near. The Maharajah of Kashmir had 

 barely obtained a footing in Gilgit, and about this period the Dogra 

 garrison had been massacred to the last man. 



