328 TO THE SU-LO-HO DELTA [Chap. IX
middle one of the broad sand ridges which it crosses near the southern edge of the basin. Striking thence south-eastwards he was to seek for the lowest course of the Su-lo-ho in the bed coming from Toghrak-bulak (Map No. 35. c. 4) and to trace it through to its termination. I myself, taking Afraz-gul with me, proposed to follow a course which would take us to the north and south of the track already surveyed in 1907 and allow us to ascertain more closely the character of the ground within the limits of the dried-up basin.
Muhammad Of Muhammad Yàgüb's work it will suffice here to mention that by proceeding from Bésh-
work. toghrak first to the north-east and then striking eastwards he succeeded in carrying his levelling
line to the western edge of the dried-up basin to be described presently. He did this by passing through a small gap in the chain of high dunes which winds round it on that side. It is for this reason that the elevation of this fringe of dunes does not appear in the end portion of the ground sectionally shown by the levelling chart.4 After the Surveyor had rejoined me at Camp cxiii he was sent across the stony plateau on the south to the terminal course of the Su-to-ho, which he subsequently mapped right through to its end in the salt lake shown by Map No. 35. B. 4.
Approach My own route on March 14th led at first along the caravan track, and even here gave rise
to old to some interesting observations. At a distance of about three miles from Bésh-toghrak I found
basin. a couple of wells, only three feet deep, marking a new halting-place and attesting the nearness of
subsoil water to the surface. A luxuriant growth of reeds and scrub extended over the flat sandy bottom of the valley up to the belt of high dunes which stretches across it and marks, as already noted in 1907, the western limit of the dried-up lake basin. The sand ridges of this belt, reached at a distance of about five and a half miles from Bésh-toghrak, rose to a height of forty to fifty feet. The dunes ran right across the valley bottom and seemed also to ascend for some distance on the gentle sloping gravel glacis of the barren hill range on the north. From the top of the broad ridge of sand crossed by the caravan track, the wide flat expanse of the basin covered on its edge with light salt efflorescence came into full view eastwards. In the distance behind it I could see the great array of high Mesas which already in 1907 had impressed me as of unmistakably lacustrine origin.
Signs of As soon as we had descended to level ground, I was struck by clear evidence of its having
recent undergone quite recent inundation. While still among low dunes I already noticed that the growth
of reeds between them was far more abundant than I remembered it to have been in 1907. Where the flat surface was reached, at a little over six miles from Bésh-toghrak, a thin fringe of young reed shoots marked the shore-line of what had manifestly been a wide temporary lake during the preceding summer and autumn. The light film-like deposit of salt efflorescence along it was just such as would be drawn to the surface by the watering of fields newly brought under cultivation. Beyond this the sand, now distinctly moist, became gradually clear of shôr and, in wide depressions, also of reeds, where the water had evidently stood too deep for their growth.
The caravan track, easily effaced in 1907 on the dry sand which then covered this stretch of ground, had now become a broad and well-marked road over the wet surface. We followed it for about two miles to the first of the tongue-like ridges, completely covered with drift-sand and flanked by isolated clay terraces, which jut out at intervals into the basin from the south. We now separated from Lal Singh, who continued by the caravan route for some four miles farther, and turned off to N. 60° W.
March Our onward march on this bearing took us over ground showing all the characteristics of a lake-
across moist bed only recently under water. Its deeper portions, winding like the lagoons that are met with sand.