DESCRIPTIVE GEOLOGY: NUMMULITIC ZONE. I97 



Nummulitic limestone. The road takes us under the Bulkot 

 (6,103 feet) crags, of which we can see nothing owing to their steep 

 angle ; but opposite us their exact counterpart is laid bare on the 

 Kagian side of the ravine in a wonderfully fine section. The strata 

 of the north face of the summit of that hill are dipping normally, 

 but lower down the dip steepens to the vertical and then becomes 

 inverted in a long, straight, steady inversion down into the ravine 

 as far as we can look. In horizontal section No. 3 this structure is 

 seen forming the mass of Bulkot summit. 



Due west of Kagian we pass a bed of brownish pisolitic iron ore 

 (the eauivalent of the coal-bearing sandstone) 6 feet thick ; and 

 beyond this grey unfossiliferous limestone. 



West-south-west of Kagian dark-brown sandstones (Gieumal) are 

 seen in a bad exposure followed by Spiti shales lying inconformably 

 on an undulating Trias platform. Over on the opposite rock face 

 Kagian village lies on the Spiti shales, and the latter are wrapped up 

 in some fine contortions of the Trias platform represented in horizontal 

 section No. 3 at the point marked a. 



The road section is now undefined and uncertain, but a sharply 

 cut-back ravine on the south-east face of Bulkot gives us the key to 

 the rest of the section down to the Hurroh R. This is represented 

 in the horizontal section by the varied folds south of the letter a. 

 Every detail of this pretty bit of folding is made plain. 



The sequence below the u k" of Dukun is as follows :— • 



Grey limestone 200—300 feet. 



Cretaceous (highly fossiliferous) • 8 inches. 



Ditto (less fossiliferous) .... 4 feet. 



Gieumal sandstone 20—30 „ 



Trias limestone (base unexposed). 



We have now reached the "longitudinal" valley of the Hurroh, 

 carrying a small stream (in the dry season) easily crossed on foot. 



( l 97 ) 



