I56 GRIESBACH : GEOLOGY OF THE CENTRAL HIMALAYAS. 



North-east of the Balchdhura pass the cretaceous rocks are over- 



Nummulitic beds of laid b y greatly altered strata with masses of 

 the Balchdhura. igneous rock. I believe them to form part of 



the N ummulitic beds of Hundes which I observed north-west of this 

 point. Beyond the rugged belt formed by this series, is seen the 

 gently undulating plateau of Hundes, sloping about 3 to 5 towards 

 the Sutlej. Judging from the horizontal stratification we have here 

 the eastern continuation of the post-tertiaries of Dongpu which I have 

 described above. 



The south-eastern extremity of the permo-trias area of Johcir 



Synclinal of Uttar- f° rm s one of the most instructive sections in 

 dhura pass. this part of the Central Himalayas. The lateral 



pressure which the entire sedimentary belt has suffered resulted in a 

 very complex flexure of the various rock systems composiug them. 

 In the Niti area, this pressure became partially relieved by a system 

 of parallel faults, of which an extended and important one is the 

 great Painkanda fault described already. Through it the younger 

 beds have been pushed partly over the older section, and thus re- 

 lieved the great lateral pressure and consequently left the sections 

 on both sides of the fault to a great extent in normal order, which 

 favoured the detailed examination of it. As I travelled to the south- 

 eastwards it became apparent that the effect of the fault became less 

 visible with each stage, and finally near the Uttardhura there are only 

 some very slight dislocations observable, such as occur in every 

 section in the Himalayas, and if they were not situated in the strike 

 of the great Painkanda fault might pass unrecorded on the map. 

 But the great pressure had to result in some change in the sedi- 

 mentary rocks, and here it has taken the form of extensive folding. 

 This feature begins to show itself clearly east of the Silakank and 

 Marchauk ridge, and increases in importance to the south-east. 

 The flexures grow gradually steeper till east of Girthi they be- 

 come inverted and most complicated. Further on it will be shown 

 that this system of parallel folding and inversion becomes still 

 more complicated, and it seems to extend far towards the easternmost 

 margin of my ground. There faults disappear almost entirely, or are 



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