There was no trace of a wall line to be seen anywhere, and as the only landmark which might be a tower was seen in the distance north-eastward, I decided to follow a cart track which seemed to lead approximately in that direction. My intention was to push on first to the north and locate the course of the Su-lo Ho. If a crossing was possible, I would detach Ram Singh to survey the river along its northern bank down to the Khara-nor Lake. I myself, after seeing him safely across, would start eastwards for remains of the old wall near the left bank. The ground passed ahead was for some four miles covered with rich scrub and tamarisks, and by the side of our cart track I noticed two rough enclosures, built of remarkably hard lumps of salty clay, which bore the look of having been used at one time or other as sheep pens.
Then we encountered a low and narrow clay ridge stretching across our route, and from its top first sighted northward a wide marshy expanse suggestive of approach to the river. In the midst of it there could be seen rising a succession of clay terraces ranged in rows, all striking east to west. The sight of them reminded me at once of the eroded clay ' witnesses ' we had passed in such numbers in the dry terminal basin of the Su-lo Ho and again in the vicinity of Lake Khara-nor. When, a mile or so farther on, we came upon the first fresh-water lagoon, and then had to ford a succession of shallow water-courses all flowing westwards and manifestly fed from the river, I could feel no doubt about the cause which had here determined the bearing of the rows of clay terraces. It was clearly the action of water which, working on the bottom of an earlier and wider fluvial bed, had first carved out ridges parallel to its own line of drainage from east to west. Then erosion by the winds blowing from the north-east had cut up these ridges into rows of terraces, and, no
doubt, this scouring still continued. This combination
of the erosive forces of running water and of wind was the very process by which I had conjecturally explained to myself the formation of those strange ' witnesses ' in
and near the dry lake basins previously met with. I
felt no little satisfaction at seeing it now illustrated by
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