On the following day a long march took us across the watershed of the range and a considerable distance down the valley that gives access to the Turfân basin. A short distance above Pa-no-pea, the route crosses a side stream coming from a snowy peak in the west about 13,400 feet high and then ascends the very narrow bottom of the main valley to the south-west. The solidity of the bridges which cross the stream in two places seemed to attest the importance attached to the route by the Chinese authorities. At an elevation of about 9,000 feet we gained the grassy slopes of a broad spur descending from a wall-like portion of the range which carried perpetual snow and probably rose to close on 14,00o feet. On the western side of the valley the last of the firs were seen at an elevation only a little above the point where the photograph in Fig. 302 was taken from that spur. About four miles from Pa-no-pea the route crossed a stream that was evidently fed by considerable snow-beds, and then led up SSW. towards the pass above another stream, which was hard frozen all over at the time.
From an elevation of about 10,000 feet the ascent lay first over a broad but very steep slope of decomposed slaty rock, overlain by a thin crust of ice. It was the result of fresh snow which the sunshine of the last few days had melted. Then the flat ridge of the pass came into sight, and the track led up to it in zigzags over bare slopes of detritus. We gained the pass after a march of seven miles accomplished in four hours and found its height, as indicated by compensated aneroid record, to be 12,280 feet. The temperature at noon was 30° F. in the sun, and an icy wind was blowing from the south. A boldly serrated ridge (Fig. 300), rising at least a thousand feet higher, overlooks the pass from the west, and apparently carries perpetual snow in its gullies down to an elevation but little above the pass. The view southwards from the pass was very limited, and on the northern side of the range, likewise, no previously intersected point could be recognized.
The descent to the south-south-east lay at first over very steep slopes of detritus. At a distance of about a mile it brought us into a narrow gorge, where a succession of very precipitous rock faces, recalling ` Parris ' in side gorges of the Indus valley between Astar and Gilgit, had to be traversed first on the right and then on the left bank. The bed of the small stream by which this gorge had been carved out was quite impassable in numerous places. Without supporting walls, built up of large boulders and rough slabs, the path leading along the last of these cliffs, at a height of about a hundred feet above the narrow bottom of the gorge, would have been quite impracticable for laden animals, probably even for ponies without loads. The walls supporting this portion of the track looked ancient, and without them the route could never have been used for any but human transport. Below this difficult gorge the valley, still cliff-bound, opened somewhat (Fig. 301). Then, from its junction with another valley coming from the north-west it offered easy progress along its winding bed to the rubble-built hovel which constitutes the roadside station of Hsi-yao-tzû. This is the last place where water can be found before reaching San-shan-k`ou, more than ten miles farther down. But, as no grass or straw was obtainable there for the animals, the march had to be continued down the valley.
From the point of junction, two miles farther down, of the At-oinak-jilga, the valley turned almost due south and became remarkably straight and open at its bottom. But all the more impressive was the contrast presented by the utterly barren slopes of the flanking spurs and the equally bare expanse of the rubble-filled flood-bed at the bottom with the fine meadows and forests that we had passed through on the northern side of the range. The great difference in climatic conditions between the regions comprised in Dzungaria, on the one hand, and the arid basin of Turfân and the vast desert area to the south of it, on the other, could not have been more strikingly illustrated than by this day's passage across the Tien-shan watershed. Even hardy scrub was scanty in the dry flood-bed that occupied almost the whole bottom of the valley ; yet the very width