STRAT1GRAPH1CAL FEATURES. 83 



(Chikkim) limestone. Only in the sections in Hundes which lie between 

 the Niti watershed and the Sutlej river did I myself see these strata, 

 but there can be no doubt that they are of wide-spread extent north of 

 the Himalayas, as similar rocks have been mentioned by Stoliczka and 

 later observers as occurring far to the north-west in the valley of the 

 Indus. Few exposures though there are of this nature, they yet are 

 of great importance in the Himalayan sections. Perhaps the best 

 exposure is afforded by the Sirkia stream ; it cuts in succession 

 through Spiti shales, the whole of the cretaceous system, and 

 exposes rocks of a very peculiar nature lower down. Next, 

 after the grey Chikkim limestone with fossils, follows a series 

 of highly altered rocks, which at first sight might be taken to 

 be members of a metamorphic series. Undoubted schists, altered 

 limestones and phyllites they seem to be, associated with igneous 

 rocks ; there is a distinct dip of the series to the north-east, and as 

 far as I could judge, it is conformable to the cretaceous beds further 

 south. Only after a long search did I find sections of distorted Num- 

 mulites in a limestone about halfway through the series. Stoliczka's 

 description of the Indus valley lower tertiary series tallies so com- 

 pletely with what I saw in Hundes, that I have no hesitation in 

 saying that the latter beds must be part of an extensive Nummulitic 

 formation, extending from the North- West Himalayas to the Mana- 

 sarawar lakes, where similar eruptive rocks have played a great role 

 (Strachey). 



I noticed the same series (the limestone often of red colour) 

 beyond the Balchdhura pass north of Milam. 



Marching still further north-east, I came upon a pepper-and-salt 

 coloured grey sandstone, very like some of the lower Siwalik sand- 

 stones, but probably unconformable to the altered Nummulitic 

 formation with a high dip to north-east. In pi. 12. in the view of 

 the Nukchung valley will be seen these lower tertiary beds dipping 

 to north-east, and overlaid quite unconformably by the horizontally 

 bedded younger tertiaries of Hundes. 



( 83 ) 



