INTRODUCTION. 131 



Sangcha on to rolling plateaus, covered with Spiti shales, which 

 extend far to the west and north-west. The southern half circle is 

 shut off to the west by an anticline of triasso-jurassic limestones with a 

 north to south strike. Both half circles are drained by branches of the 

 Kiogarh river, meeting in a ravine that traverses the northern 

 termination of the anticline just mentiond halfway between Talla 

 Sangcha and Laptal E. Gs. From the northern half circle the Balch- 

 dhura Pass, 17,590', leads into Hund6s (road to Chilumkurkur) 

 and the southern one is connected with that country by three practic- 

 able passes, viz., a nameless pass between Kiogarh No. 3 and No. 4 

 approximately 18,000', the Kiogarh-Chaldu pass, 17,440', and the 

 Kiogarh-Chirchun pass, 17,960' (road to Chirchun E. G.). 



The average height of the district is very considerable, the lowest 

 point (near junction between the two main branches of the Kiogarh 

 river) being approximately 13,000', the greatest vertical elevations 

 rising up to more than 19,000'. At no point is the boundary range as 

 low as 17,000'. 



The striking contrast in the configuration of the landscape seen 

 everywhere along the great Himalayan watershed is of course con- 

 spicuous in this area. To the north, speaking generally, the country 

 descends slowly to an undulating high plateau, while the land south of 

 the watershed is deeply eroded into steep bold cliffs and narrow 

 gorges. My work lay on this side of the watershed where there are 

 much better sections than in the Chirchun area, which forms part of 

 the Tibetan high plateau. 



The extent of the whole block-bearing area 



i, P l? ha u\ e e * Unt ° f cannot be deliminated in detail. We know 

 the block-bearing area. 



from the researches of the expedition of 1892 

 that it reaches south as far as Kungribingri, 19,170', and east beyond 

 the Chaldu river. But how far it extends to the north can so far 

 only be guessed at. At any rate it includes the Peaks Ghatimemin, 

 18,700', and Sami, 17,920', of the Indian Trigonometrical Survey map. 

 From the frontier I could see that exotic blocks occur several miles to 

 the north of Balchdhura No. 2. Exotic blocks may also occur to the 



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