318 TO THE SU-LO-HO DELTA [Chap. IX
more than six to eight inches above the cup-like depressions in their centre, this surface was less trying than that over which our passage of the ancient sea-bed had taken us. On this section of the march we encountered three or four small channels holding an apparently stagnant solution of salt. They were nowhere more than four feet wide, and seemed to run with many windings in the general direction from north-east to south-west. Both banks were encrusted with pure white salt, and this being hard facilitated the crossing. I noted that the bank on the north side was usually a foot or two higher than the one opposite. We could see to the south, above the hazy air that oscillated over the salt waste, the fantastic shapes of Mesas raised by mirage into the semblance of huge Stûpas or spires. The highest of them remained curiously constant in its position, and its distance as indicated by intersection on the plane-table proved in the end correct.
Strip of At a point close on twelve miles from camp we were held up by a strip of boggy salt-covered
salt bog. ground showing a winding band of white brine in the middle (Fig. 181). The strip was from twelve to fifteen feet wide, and it took time before a place was found where, by putting down felts, it became possible to take one camel after another safely across. Beyond this the surface changed to a hummocky salt-encrusted clay of great hardness. Its sharp-edged crusty lumps made progress for the next two and a half miles most trying. Yet we had covered less than a mile from the boggy strip when the first stalks of living reeds were met with, growing on ground that seemed utterly incapable of supporting life. Deposit of loess dust between the stone-like lumps of salt-permeated clay may account for this thin strip of reed growth.
Reunion At last we reached a sandy patch close to the northernmost of the line of Mesas we had steered
with Lai for. They proved to be, as expected, the string of eroded clay terraces marked four miles to the
Singh at west of Kum-kuduk by our survey of 1907.6 Half a mile farther we reached, to the men's great
Kum- y y, g
kuduk. delight, the lonely caravan track representing the thong yol, the ` high road ', to Tun-huang. Some
small disappointment still awaited us on arrival at the low sandy hillocks dotted with scrub, where I remembered our Camp 149 of 1907 to have stood by the side of a shallow well. For the track of Lai Singh's cyclometer wheel, which we had eagerly followed in the hope.of a prompt reunion at our appointed rendezvous, still led onwards. Five weary miles more had we to tramp over heavy sand before we found Lai Singh and his little party encamped on the open reed-covered plain by the side of a newly dug water-hole. He had halted there in the preceding December, and with excusable preference for his own mapping had thought it safer to await us there than at the point which our survey of 1907 indicated !
Lai Singh's The exhausted condition of the camels, no less than the necessity of awaiting the arrival of the
convoy with the heavy baggage, supplies, and ponies from Mirân, made it necessary to halt at
up sea-bed. Kum-kuduk (the ` sandy well '). I used the first day of it to go carefully with Lai Singh over the plane-table record of the route, well to the north and east of our own, that he had followed in accordance with my instructions. I t had taken him first along the foot of the hill range east of Altmish-bulak to the salt springs of Yetim-bulak and Kaurük-bulak, which Abdurrahim knew well from his boyhood and which Dr. Hedin had visited in 1901 (Map No. 32. A. 2, 3). From the latter spring he marched down the Sai to the east-south-east, and after proceeding about ten miles came upon the expanse of the salt-encrusted sea-bed. It proved here, at its northern extremity, far wider than where we had crossed it. The party, after passing a belt of salt-coated Yârdangs, evidently an outlier of the ` White Dragon Mounds ' that we had met between Camps ci and cii, had therefore to spend a very trying night at Camp 89, amidst hummocks of hard salt. Lal Singh's aneroid, a remarkably reliable instrument, gave the elevation of the Yàrdang belt as about a hundred feet higher than that of the flat salt-crust surface at this camp. Next day they had to cover fully
6 See Serindia, v. Map No. 67. D. 4.