DETAILED DESCRIPTION OF THE AREA. I5 1 



IV- DETAILED DESCRIPTION OF THE AREA. 

 {a) The neighbourhood of the Balchdhura Pass. 1 



The boundary range rises up north of the Balchdhura pass to an in- 

 significant peak, Balchdhura, 18,110/ whence it runs north-west to a 

 second point marked on the Trigonometrical Survey map, Balchdhura 

 No. 2, 18,500'. Between these two points the range describes 

 a curve * wiih its convex side towards Hund6s. Within this are two 

 high peaks, the Balchdhura heights, as I call them ; the eastern 

 measuring 18,900' the western slightly less. 



Structure of Flysch. — To the west of Balchdhura No. 2 the bound- 

 ary range is composed of Gieumal sandstone with remains of the 

 upper flysch series, viz , the red shales and limestones (4a) which 

 alone are preserved. 



About half a mile west of Balchdhura No 2, the upper flysch is 

 faulted against the Gieumal sandstone. On the slopes to the south and 

 south-east of the Balchdhura heights a magnificent flysch section, the 

 best I have seen, is exposed. 



The beds have a constant dip of 10 to 15 to the north-east. 

 Ascending this section we meet with a certain amount of folding in 

 the black shales {4b), but higher up it is almost undisturbed as far as 

 the topmost flysch beds, where there is a very striking feature. 

 Tuffs, almost horizontal, first green, then red, end in a sort of narrow 

 ledge, to which a debris slope descends from a small thickness of red, 

 folded tuffs. This upper, folded tuff band yielding easier to weather- 

 ing than the slightly inclined tuffs below, the formation of a ledge and 

 a debris slope is easily understood, but the question, how the sudden 

 change from unfolded to folded beds can have been brought about, 

 is more difficult to answer. It must of course be due to faulting, 

 but the latter is of an unusual and remarkable character. 



The ledge, with its accompanying features, can be seen following 

 the curve of the boundary range, for at least 2 miles, from Balchdhura 



1 Pis. 1 and 3 ; section 1 on pi. 12. 



2 Not marked on the map. 



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