14- GRIESBACH: GEOLOGY OF THE CENTRAL HIMALAYAS. 



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Chapter II.— -Physical Features. 



If it were possible for us to obtain a bird's-eye view of the high- 

 lands of Central Asia, then we should see a high table-land sur- 

 rounded by a rim, which latter consists of a system of parallel 

 ranges, in which are situated some of the most gigantic mountains of 



the world. 



This is the Tibetan plateau with its fringing rims of the Himalayas 

 and the Kuenlun ranges. On the high table-lands of this region we 

 find the headwaters of several great rivers, which, flowing through 

 gaps in the hill barrier, skirt it along its southern sides and empty 

 themselves into the plains of India, after traversing the entire width 

 of the mountain belt of the Himalayas. 



The geologist, however, sees in the mighty ranges which not 

 only fringe this high plateau, but also traverse it in more than one 

 line, the result of an extensive wrinkling and folding process, which 

 has taken place all over the present continent of Asia, and which 

 caused long lines of gigantic flexures to form, many of them reversed 

 and often pushed one over the other along lines of dislocations, — 

 folds which by degrees lifted the great thicknesses of the palaeozoic, 

 mesozoic, and even tertiary deposits to the stupendous altitudes in 

 which we at present find them. 



Between these lines of flexures the later tertiary and recent 

 deposits have been laid down in horizontal deposits, thus assisting to 

 form the great table-lands of Tibet and the Gobi. Amongst the high- 

 est of these plateaux is that part of Tibet called Gnari-Korsum, or by 

 the Indians, Hundes (land of the Huns). Wide-spread, horizontal 

 beds of younger tertiaries nearly fill the basin-shaped synclinals 

 between the systems of flexures. The latter form the fringing " rim ' ; 

 to which I likened the great parallel ranges of the Himalayas. 



The lowest portion of the elevated plateau of Hundes reaches a 



mean sea level of about 12,000 to 16,000 feet, 



Hundes plateau. 



and is generally a bare, bleak plain, in which 

 the Sutlej with its side drainage has eroded deep gorges, so charac- 



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