VILLAGES.
October, 1847.
Throughout Nubra, the villages, with scarcely an exception, occupy the surface of the low platforms of alluvium which fill up the funnel-shaped terminations of the ravines. In Tibet the size of the villages, and the extent of cultivation by which they are surrounded, entirely depend on the supply of water and on the facility with which it can be diverted from its bed for purposes of irrigation; and as, in this district, the width and horizontality of the alluvial tracts are very favourable to the industry of man, the villages are in general large and surrounded with much cultivation. Indeed, a super-abundance of water is in general indicated by the swampy banks of the irrigation canals, as the water, oozing through the loose gravel of the platforms, produces a dense jungle of Hippophaë scrub, which makes the cultivated tracts conspicuous, even in winter, when the trees are bare of leaves and the fields of crops.
This copious supply of water no doubt depends on the great elevation of the surrounding mountains, which everywhere rise, if not above, yet almost to the level of perpetual snow, which is about 18,000 feet, so that at the head of each little stream there is either a glacier, or a snow-bed which does not entirely melt till the latter end of autumn, affording therefore a nearly perennial supply of water. Even in the hottest months slight falls of snow are of occasional occurrence at all elevations above 16,000 feet; and as every range rises much above that height, a small addition to the supply is thus obtained.
The villages have generally a few fruit-trees, as well as a good many poplars and willows, which yield almost the only timber the inhabitants can command. The walnut and Elæagnus, both of which trees find their upper limit in Nubra, are so extremely scarce that they are not available for such purposes.
In most parts of Nubra the soil is very generally saline, the dry grassy plains which are common on the banks of the streams being generally covered with a copious efflorescence of carbonate of soda; while the abundance of Salsolæ and other Chenopodiaceous plants on the dry alluvial plains, and even on the rocky hills, seems to prove that the saline matter is not confined to the immediate vicinity of water, or to the lowest levels, but is very generally diffused over the surface.
VALLEY OF NUBRA RIVER.
October, 1847.
The valley of the Nubra river, for upwards of twenty miles, is very similar in general character to that of the Shayuk. The same wide gravelly expanse occupies its centre, forming a plain of one or two miles in width, through which the river runs in many branches. A great part of this gravelly plain, particularly on the right side of the valley, is covered by a dense thicket of Hippophaë, extending continuously for four or five miles, usually impervious, except in certain beaten tracts, and tenanted by vast numbers of hares. The gravel on which this jungle grows is almost on a level with the river, so that it is very generally swampy, and traversed here and there by little streamlets of water. The Hippophaë is here a small tree, attaining a height of fifteen feet, with a short thick trunk and stiff crooked spinous branches.
CHIRASA.
October, 1847.
In several parts of the course of the Nubra river, low hills rise in the valley, isolated, or nearly so, from the mountain ranges behind, and forming, therefore, a remarkable feature. On one of these, on the right bank of the river, is situated the little fort and village of Chirasa, a considerable mass of houses, of a class a little better than those usual in the district, and conspicuous from their elevated position. The rock on which they stand is composed of a hard porphyry, which has been injected from below, and has displaced the black slate, which is the more usual rock in the lower part of this valley.
In the lower part of the ravine behind the town of Chirasa, the alluvium is more extensively developed than usual in this valley, where aqueous action seems in a great measure to have removed the accumulation of detritus, which once, no doubt, occupied the whole valley. Beds of gravelly conglomerate, at times passing into fine clay, may here be seen, at a height of perhaps 1000 feet, on the mountain-sides in isolated patches, generally faced by cliffs, in which a tendency to horizontal stratification is observable.