tation is at all events very sparse — has, under the incessant filing of the wind, given place to a relative depression; but Basch-toghrak itself has been preserved by the binding force of the roots of the toghraks. At the same time the drift-dust which has dropped upon the oasis has been retained there by the trees and their roots; whereas upon the circumjacent bare soil this æolian deposit has been unable to maintain its footing, but has always been swept on farther by the wind.
Our path continued to wind on through a belt of especially numerous tamarisk-mounds, unusually big and lofty, and crowned by living bushes. This conformation, again, bears witness to the influence of the wind. Let us suppose that these tamarisks originally took root on the perfectly level ground (a—a in fig. 13), then the points where the bushes are growing become protected against the erosive force of the wind, and it is only the intervening spaces (indicated by arrows) that are exposed to it. Consequently these intervening spaces are gradually hollowed out to the successive positions b—b, c—c, d—d, e—e, the elevation of the tamarisk-mounds growing at the same time relatively higher with each successive downward step of the surrounding soil. Hence, when one rides amongst a series of mounds of this description, 3 and 4 m. above the general level, one may safely take it for granted, that the summits of the mounds, where the tamarisks rest, were once au niveau with the general level of the country. In the sequel we shall come across yet other proofs of the correctness of this reasoning.
The belt of tamarisks is succeeded by hard and perfectly.barren saj, i. e. hard, sterile soil with a thin sprinkling of gravelly débris on the surface. This superficial covering gradually increased in quantity as we approached the mountains, while an occasional solitary tamarisk or jantak bush was the sole representative of the vegetation. The saj formation is traversed by the lower part of a dry torrent or bed of a sil, its course being indicated by a double line of erosion faces, barely a foot high, and frequently indistinguishable, inclosing between them a winding ribbon of fine sedimentary clay, almost white in colour. Here the steppe scrub is more abundant, although the water-supply must be of the very scantiest, being limited to the very rare occasions when the rain torrents of the Kuruk-tagh succeed in getting thus far down. Farther along too, on the sides of the watercourse, there is a sprinkling of steppe scrub, growing on small mounds. The rest of the way, to the foot of the mountains, we travelled up this watercourse, which issues from the glen of the Suget-bulak. The scenery is dreary and monotonous, and the soil barren. And so gentle is the ascent towards the Kuruk-tagh that it is imperceptible to the eye. The desolate saj stretched all around us as level as the sea; the only animals we saw all day were a couple of shy antelopes. During the march the contours of the mountains, which had been visible ever since we left the Kontsche-darja, came out more and more distinctly. When we reached the lower part of the saj we were able to make out certain of their details — the mouths of the glens, the hollows of the mountains, and their shadows. From the same spot we were able to perceive, although indistinctly, the belt of vegetation alongside the Kontsche, showing like a dark line on the southern horizon, where it framed in the grey, monotonous
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