l88 GRIESBACH : GEOLOGY OF THE CENTRAL HIMALAYAS. 



carboniferous white quartzite (8) is overlaid conformably by the 

 permian black Productus shales (9), which about 2 miles south-east of 

 the Sangchuma camping-ground are cut off by a reversed fault, white 

 quartzite (8) being again pushed over it. This is evidently the same 

 fault as observed five miles off on the north-east slope of the Lebung 



pass. 



Several streams (Birthir G£dh, etc.) rise amongst the high ranges 



which divide Tibet from this part of Kumaun, 



Bithir Gadh. . . , f r 



amongst which points of over 21,000 ieet occur; 



these streams unite, and flow in a deep gorge into the Kuti Yangti ; 

 exhibiting good sections during their course. On entering this 

 gorge I found myself traversing a large reversed synclinal, or 

 rather system of synclinals, of carboniferous rocks, white quartzite 

 (8) which incloses again a good section of the permo-trias. The 

 black Productus shales (9) are less friable and contain more lime- 

 stone partings. The overlying lowest trias {Otoceras stage (10) 

 is a succession of hard limestones of dark-grey colour, with scarce- 

 ly any shales to divide them. About 100 to 150' of very hard 

 light-grey limestone, with sections of Ammonites on the weathered 

 surfaces, represent the middle trias with Muschelkalk types (n), 

 lithologically not different from the same beds elsewhere further 

 north-west. Overlying it I found very hard, dark, almost black lime- 

 stone in thick beds, in which I did not see a trace of fossils. 

 Numerous calcspar veins traverse it and its general aspect is 

 not unlike the devonian limestone (6), but its position in the 

 synclinal overlaying the lower triassic rocks clearly indicates it as 

 the representative of the upper triassic Daonella limestone (12). 

 Proceeding further up the Thumka Gidh gorge, I came upon a suc- 

 cession of palaeozoic beds as indicated in the figured section 2, pi. 9. 

 From the presence of the red Crinoid limestone (7, a), inclosed 

 within a great thickness of white quartzite (8), it seems to me 

 evident that I traversed there two more, and moreover highly 

 compressed, reversed flexures. A descending section from white 

 quartzite (8) down to the bright red quartz shales (3) below which 

 ( 188 ) 



