88 



GRIESBACH : GEOLOGY OF THE CENTRAL HIMALAYAS. 



the different formations of that ground until I reached the higher 

 valleys north and north-east of Niti. Though a very highly elevated 

 area, the ranges in that part of the Himalayas are singularly free from 

 ice and snow, and the slopes being frequently easy of ascent, I 

 obtained some very good sections, which remained for the rest of my 

 work in the Himalayas keys to interpret more difficult ground. I 

 may here remark that not only the succession of the groups, but also 

 the general lithological character of the beds composing them, varies 

 but very little throughout the extent of the Central Himalayas, from 

 the frontiers of Nepal in the south-east to their north-western limits in 

 the Spiti valley. The only considerable difference discernible in the 

 sections occurs in the upper carboniferous system, as will hereafter be 

 shown. Later on, after I had finished the ground south-east of the 

 Niti sections, as far as the Nepal Frontier, I found another oppor- 

 tunity of visiting the sections in the Painkanda area, and so was 

 able not only to correct the results of my first season's work, but also 

 to again compare work already done with the key sections of Niti. 



It may not be out of place to remark here that all the ideal sections 



given with this report, have been constructed 

 on a natural scale, i.e., the scale of the vertical 

 and horizontal dimensions is the same, I mile = I inch. The recorded 

 thickness of each individual bed and group has also been drawn 

 to this scale as far as it was possible to do. 



All the sections in this report are constructed from a base line 

 assumed to be drawn at 10,000 feet above the sea-level, which is 

 about the height of the lowest valley within the area of sedimentary 

 rocks, and the heights given are generally those recorded on the large 

 scale (1 mile = 1 inch) Survey of India maps, supplemented by heights 

 determined by myself with a Newman's standard mercurial baro- 

 meter. 



To obtain an approximately correct outline for such ideal sections 



r* ,. „f;~„ ^f e^ without the help of a map which shows true 

 Construction 01 sec- r r 



contour lines is always difficult, but I believe 

 ( 88 ) 



Scale of section. 



tions. 



