Page:Mongolia, the Tangut country, and the solitudes of northern Tibet vol 2 (1876).djvu/94

74 and leaving the bulk of our baggage at Chobsen, on July 22, 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 surrounded on all sides by mountains, forming a continuation 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