The Wonderful Mekong 141 
where it begins to separate from the Yang-tze, we get, first, 
the arid region in the deep gutter itself; secondly, going 
eastwards and ascending, forest; thirdly, grass-land; and 
finally above the Yang-tze, scree; which is exactly the 
sequence in the horizontal plane which we find in vertical 
extension on the Mekong-Yang-tze divide further south. 
That is to say, the grass-land plateau is simply the equiva- 
lent of the alpine grass-land to which we have already 
referred as a prominent feature of that ridge. 
Under the miserable conditions I described before this 
digression we resumed our march after a halt to readjust 
the loads. 
Below the gravel region we came again upon cliffs of 
limestone, and of red sandstone conglomerate with water- 
worn pebbles embedded in a hard siliceous matrix. Ap- 
proaching signs of habitation we presently came upon an 
image of Buddha, extravagant in design and execution, 
painted in crude colours on a smooth limestone cliff: close 
by was the village of La-wu-rah, amidst terraces of barley 
and buckwheat. 
Away to the west, in Tsa-riing on the other side of the 
Mekong, snow mountains appeared, phantom-like amongst 
the clouds. This range, of which I was destined to get a 
much better view later, is known to the Tibetans as Ta-miu, 
and is evidently the northward extension of the K ‘a-gur-pu 
ridge on the main Mekong-Salween watershed, but whether 
it is continuously above the snow-line from K‘a-gur-pu 
onwards is a point I could not decide. 
As we descended, the valley took on more and more 
the character of the now familiar arid region. Granite 
and metamorphic rocks re-appeared, and stunted bushes of 
Sophora vicitfolia took the place of forest. Presently we 
crossed the terracotta-coloured stream, here rather broader 
and shallower than above, but though we could hear the 
boulders grating and rattling against each other as the 
flood swept them along, and the ponies were a little shy of 
entering the water, we had no real difficulty in crossing. 
Later our cavalcade floundered into a quagmire in the 
valley bottom, and further on we found the cliff path 
blocked by two enormous boulders which had rolled down 
the mountain side. Happily the largest of them was nicely 
