TRANS-HIMALAYA AND TIBET 39 



the northern is formed by the central lakes discovered by Nain 

 Singh and myself, and the southern by the Indus-Tsangpo 

 valley." 



This zone of numerous lakes to which Dr. Hedin refers 

 varies in level only from 15,100 to 15,700 ft. above the sea and 

 evidently marks the site of a continuous depression, extending 

 from west to east along the southern border of the Tibetan 

 plateau. Starting from the Rartse plain (15,695 ft.) in the west, 

 we find a close and continuous linear succession of the following 

 lakes : Ngang-tsing-tso (15,573 ft.), Shovo-tso (15,696 ft.), Tabie- 

 tsaka, Tarok-tso (15,180 ft.), Terinam-tso (15,637 ft.), Dangra- 

 yum-tso, Ngang-tse-tso (15,417 ft.), Marchar-tso, Kyaring-tso 

 (15,541 ft.), Makiou-tso, Bul-tso, Ring-tso, Shudun-tso and 

 Nam-tso or Tengri-nor (15,190 ft.). This depression, extending 

 mainly along the thirty-first parallel, is indeed so pronounced 

 a feature in the Tibetan plateau as to cause Nain Singh ^ (the 

 original discoverer of this lake-system) to state that " along this 

 line a cart might easily travel eastwards to the Nam-tso lake 

 (Tengri-nor) without meeting a single obstacle cii route and 

 that this plain is as a rule confined between mountains which 

 run parallel to the direction of the road." 



To the north of this zone all the ridges traversing the plateau 

 show a general direction from east to west without imposing 

 any serious impediment to the traveller; and their intermediate 

 troughs, with their rivers and lakes, exhibit the same latitudinal 

 orientation. In fact, Littledale,^ in marching southwards from 

 the Kuen-lun to the Tengri-nor — a distance of six degrees — 

 states that "we never saw a single mountain range till we 

 came to the Nien-chen-tang-la," on the south coast of the 

 Tengri-nor. 



To the south, however, of the lake-zone, especially between 

 the eighty-second and eighty-fifth meridians, these latitudinal 

 ranges have given place abruptly to the Trans-Himalayan 

 system of parallel ranges, running at an acute angle to the 

 Tibetan ranges, viz. from N.N.W. to S.S.E., of which the chief 

 are named successively (from west to east) Surnge-La, Ding-La, 

 Lavar-gangri, Pedang, Sur-la, Kapta and Lunkar. Farther to 

 the eastward, the direction of these ranges curves round so that 



' Captain Trotter's Report on the Trans-Himalayan explorations of 1873-4-5. 

 ^ "A Journey across Tibet," etc. Ccogr. Journ. 1896, vol. vii. p. 463. 

 London, 



