74 HIGHLANDS OF KAN-SU. 



and leavino- the bulk of our ba^'Sfao'e at Chobsen, on 

 July 2 2, we started with four mules and two horses 

 for the Tatung- valley near Chertinton, 



I must now make a short digression, in order to 

 give a general sketch of the mountains in that part of 

 Kan-su which we visited, viz. north and north-west 

 of Lake Koko-nor. 



The confined basin of this alpine lake is sur- 

 rounded on all sides by mountains, forming a conti- 

 nuation of the ranges covering North-eastern Tibet, 

 and the basin of the upper Hoang-ho. From this 

 point, i.e. from the sources of the river, the system 

 bifurcates, passing north and south of Lake Koko- 

 nor, and continuing a long way to the west ^ forming 

 a peninsula of high land defined on the south by the 

 salt marshes of Tsaidam, and on the north by the 

 vast plains of the Gobi. Towards the latter, as we 

 have seen, the mountains form a rampart supporting 

 the plateau, on which lie Koko-nor and Tsaidam, 

 and separated from the still more elevated uplands 

 of Tibet by the range of Burkhan Buddha. 



Turning to Kan-su Proper, or rather to that part 

 which we explored, we find it to consist of three 

 parallel chains of mountains : one bordering the 

 plateau on the side of Ala-shan, the other two 

 piled upon the table-land, and following the course 

 of the most important of its rivers, the Tatung-gol. 

 On the east, as we approach the Hoang-ho, the 

 mountains diminish in size, while on the west their 



' We were told by the natives that this range continued for up- 

 wards of 300 miles to the west of Lake Koko-nor. 



