glaciers, though possibly there are some in a rudimentary stage. It was not possible to arrive at any sure conclusion as to a former glaciation of this region with far-reaching glacier-arms, which could have scooped out this lake; at all events I failed to discover any traces of it. There were neither striations on the hard rock, nor erratic blocks, nor moraines; not even the smallest flattened rampart that could be regarded as the remains of an ancient moraine. Nevertheless the bare rocks frequently showed a tendency to rounded forms, such as might have been produced by a progressive glacier-stream. As a rule, the mountains in the vicinity of the lake are covered with disintegration products and soft grass-grown earth, and usually the bare rock crops out only at the crests and culminating points in the form
of ridges and steep masses or pinnacles and denticulations, these last showing clearly that they were not formed by ice, but, on the contrary, if the region was glaciated, must have projected above the icy covering like nunataks. Now since, as I shall show in a special chapter lower down, all the lacustrine regions of Tibet occur in close proximity to the loftiest and biggest mountain-ranges, it is impossible to avoid the impression, that the origin of these lakes is in some way or other connected with the snow and ice which gather on those mountains, and since moreover most of these salt lakes are undergoing a process of desiccation, it is a pretty obvious inference, that the rainfall must formerly have been far more abundant than it is now. Those portions of the mountains which ascend above the limit of perpetual snow would then be in a position to give rise to immensely more extensive and more prolific firn-fields than they are now, and consequently to incomparably greater glacier-arms. It is not however necessary to suppose that the entire country was under glaciation. Even to-day it is the rarest thing possible to find a mountain-
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