234 The Last of the Mekong 
throughout, stretching from the river to the base of the foot- 
hills from which the numerous streams debouch. Behind, 
the divide rises steeply, its buttress-like ridges sweeping 
down in grand curves to merge imperceptibly with the 
undulating foot-hills. 
The chief region of cultivation is this alluvial platform, 
though the wide valley mouths are also extensively terraced ; 
the chief region of occupation, the foot-hills, where in each 
little pocket a Shan village is tucked away. The rugged 
mountain range between the Salween and Shweli is densely 
forested except along the immediate crest. On the left bank, 
however, the dry brown mountains dip almost straight down 
into the river, leaving but little room for cultivation, since 
the torrents, far fewer in number, instead of building out 
wide alluvial platforms, have burst through the final range | 
by cutting out deep gorges for themselves. Thus no foot- 
hills have been formed, and it is only here and there in 
favoured localities that the slopes are sufficiently gentle 
to be terraced, villages being few in consequence. It is 
evident, therefore, that though the Salween valley receives 
a far more copious rainfall than does the Mekong gorge, this 
extra precipitation is itself confined almost entirely to the 
Salween-Shweli divide. 
The crest of this range is plainly visible from the 
valley, as far as the eye can reach north and south, being, 
indeed, but a few miles west of the river and within 
a day’s climb; but the summit of the Salween-Mekong 
divide, hanging immediately above the latter river, is not 
visible at all for, owing to the erratic courses of the streams 
flowing to the Salween on that side, a secondary ridge has, 
as already remarked, been blocked out in front of the main 
watershed. The place of the foot-hills is really taken by 
the broad valley intervening between the two ridges, on 
the upper courses of the torrents which, in response to the 
distribution of the rainfall, show the reversed type of valley 
structure already described. That there is only a slight 
rainfall on this side immediately above the Salween is amply 
demonstrated by the comparative poverty and scantiness of 
the vegetation, and still more plainly by the straight-sided 
narrow gorges through which the torrents enter the river. 
The result of these climatic differences between the 
