THE MONGOLS OF TSAIDAM 1093 
of a last narrow pass or gorg'e, caused by the stream 
pressing against the rocks on the right-hand side of its 
course, we came upon an unusual sight — the horizon 
forming a perfectly straight line in the far, far distance. 
After that we quitted the stream ; but at the end of an 
hour or so once more got back into its dry channel. It 
was now getting not only broader and leveller, but also 
freer from stones, for it is only in summer that it carries a 
supply of water. We rode along the dry bed for the rest 
of the day. The mountain - spurs which bordered the 
valley of Harato gradually diverged from each other ; 
although their outer ramifications still continued visible in 
both directions, east and west. 
At the end of the valley vegetation ceased nearly 
altogether. The plain sloped away almost imperceptibly 
towards the north, and gradually became more and more 
barren, until finally it passed over into absolute desert, 
with occasional chains of low sand-dunes, which seemed to 
have been blown up by the prevailing westerly winds. It 
was a dreary landscape, utterly destitute of life, with not 
a trackway to be seen. A death - like silence reigned 
throughout the length and breadth of the unbounded 
plain ; which was irksome to the eyes after such a long 
sojourn among the world of mountains in Northern Tibet. 
Turning in my saddle and looking back, the vast mountain- 
chain with its snow-clad summits looked as if it were 
painted on a flat background — the effect of the wonder- 
fully clear atmosphere. I could not even distinguish the 
exit of the glen out of which we last rode. 
The basin of Tsaidam thus possessed many points 
of resemblance with the basin of the Tarim. In both 
the oases are separated from the foot of the mountains 
by a belt of desert ; in both, the streams die away in 
the sand, although in Tsaidam the central parts of the 
basin are occupied by a series of extensive marshes, 
leaving room for only a comparatively narrow strip of 
desert all round them. 
Hour after hour we rode on towards the north, overtak- 
ing the camels hours before the shades of night began to 
