AN EXPLORATION OF EASTERN BHUTAN
heads lying about. The natives explained this by saying that in winter wolves attack and kill the males, who in consequence of the weight of their heavy horns cannot get quickly over the ground and out of reach. From the ridge I followed a stream which took me the whole way to the Nyeru Valley, but which is not marked on the map Ryder made at the time of the Lhasa Mission. This may be accounted for by the very narrow gorge through which it passes on entering the valley. The Bhutan boundary runs right up to the head of the Nyeru Valley, and from Nelung the Wagya-la, over which there is a trade route to Bhutan, can be seen. We had a long, weary march across a flat plain in hail and rain before reaching Nelung, where tents had fortunately been pitched by the headman, and very welcome they were, as all our things did not come up till past eight o’clock, and it continued to rain and blow hard nearly all night, though it was fairly fine towards morning.
I discovered that the Nyeru-chhu takes its rise in the high snows not far from the source of the Kuru-chhu. It breaks through the dividing ridge between the lake basin and the Nyeru Valley under the snow, and then takes a right-angle bend to the north and comes down past Nyeru.
All the valleys I have seen to the north of the watershed—viz., from Eastern Bhutan to some distance west of Sikhim—appear to have at some remote period been much more densely populated than at present. At every turn I came on ruins of habitations and remains of old irrigation channels; and overcrowding may possibly account for this migration over the Himalayas into the comparatively hot valleys of Bhutan, in which no Tibetan would willingly settle, though he might be forced by circumstances to do so. This also raises the interesting question of the former climate of these parts. I think there is no doubt that there must have been considerably more rain, and everything appears to support this view—the receding
209
