[Sidenote: GIAH RAVINE. _September, 1847._]
On the morning of the 28th of September we resumed our journey towards Le. By crossing the Tunglung pass, we had again gained the eastern slope of the ridge dividing the waters of the Zanskar from those of the Indus. The Giah stream flows towards the latter river with a north-easterly course, and two marches of little more than seven miles each, brought us to the banks of the Indus at a village called Upshi. For the first mile after leaving Giah, the valley was somewhat open, with steep banks of alluvial conglomerate; it then contracted rather suddenly into a narrow ravine, with steep rocky walls, composed of highly inclined strata of conglomerate and sandstone. Owing to the diminished elevation, the vegetation was considerably more recognizable than it had been for the last week, and several shrubby plants were seen which had long been absent. _Ephedra_ was common in the crevices of the rocks, and the Tibetan rose and a small shrubby _Lonicera_ grew on the gravelly banks of the little stream.
[Sidenote: REMARKABLE GORGE. _September, 1847._]
At Miru, a considerable village where we encamped, the valley expanded into a little plain, filled as usual with alluvium, and covered with cultivation. A few poplar-trees occurred in the village. The ravine contracted immediately below this place, and was, if possible, more narrow and rocky than the day before, as the little stream had to be crossed not less than four or five times in as many miles, on small wooden bridges of rough planks. A very beautiful Labiate shrub, a species of _Perowskia_, with bright blue flowers, which I afterwards found very abundant in the Indus valley from 12,000 to 8000 feet, was here met with for the first time. Close to its junction with the Indus, the ravine expanded into an open plain, well covered with houses and enclosures, with scattered poplar and willow trees, as well as a few apricots, and traversed by canals of irrigation conducted from the little Giah rivulet. The Indus is here not more than forty feet wide, flowing swiftly over large boulders, and quite unfordable.
Throughout the whole course of this very remarkable gorge by which we descended from Giah, the rock continued to be conglomerate, alternating with strata of sandstone and of a very friable slate. The conglomerate was extremely hard, and generally of a dark brown colour. The matrix, which had often a semi-vitrified appearance, was not less hard than the enclosed stones, which were all rounded and very various in size and composition, jasper rock, granite, and quartz being all seen. The sandstone which accompanied the conglomerate varied much in colour, various shades of red, brown, and green being predominant. It was also extremely hard. These strata, which were highly inclined, often nearly vertical, were in general well marked, in consequence of the beds of hard sandstone and conglomerate being thrown out in relief by the more rapid decay of the soft slates with which they alternated. The dip was everywhere very variable, and several very distinct sections were displayed, where it was evident that the strata were curved and sinuated. The curves observed were convex below; the strike of the strata was nearly perpendicular to the general direction of the ravine, or from north-west to south-east.