Sec. viii] FROM THE LOU-LAN STATION TO ALTMISH-BULAK 275
on a straight line drawn from the castrum L.E. to the end of the northernmost branch of the Kuruk-daryâ and to the ` Tati ' area marked on it in Map No. 29. c. 3.
From that point westwards it appears to me quite certain, in view of unchanging and clearly defined physical features, that the line of the ancient high road must always have kept as close to the foot of the Kuruk-tâgh glacis as consideration for water-supply, grazing and fuel would permit ; for the level Sai of gravel along the edge of the glacis would in ancient times, just as now, have offered the easiest ground for traffic. Protection was there afforded from all those troubles of flooding, shifting banks, drift-sand, &c., with which roads close to rivers are always beset under the conditions of the Tarim basin.ls The route leading from the Lou-lan station L.A. towards Ying-p`an could not have gained the natural highway along the edge of the Kuruk-tagh glacis and the river-bed skirting it by a shorter line than the one running to the north-west and striking the gravel Sai near the point marked by Lal Singh's Tati'. And that the route actually followed this line is made highly probable by the fact that along it there stretches, as the map shows, the series of ruined Stûpas, Buddhist shrines and residences between L.A. and L.B. which I explored in 1906.17
The remains and the records found at L.A. leave no doubt that the ruined station at that spot was, anyhow during the closing period of the occupation of Lou-lan, the administrative centre of the territory through which the Chinese ` route of the centre ' passed., There must have been adequate reasons justifying its location at this point, such as facilities for irrigation and the consequent command of agricultural resources. But whatever these considerations may have been, they could not do away with the fact that travel by the route leading first from L.E. south-westwards to the L.A. station and thence north-westwards to the nearest point at the foot of the Kuruktâgh glacis involved a not inconsiderable detour. It is therefore probable that the direct route between the first and the last points was also frequented to some extent, and this may help to account for the traces of ancient occupation that we encountered between Camp 84 and the edge of the glacis.
As we continued our march to the north-west from the remains of the ancient dwelling described on the preceding page the Yârdang ridges became steadily lower and flat patches of ground, obviously levelled down by wind-erosion, such as I had noticed already before reaching the ruin, became ever more frequent. The sand was growing coarser as we approached the edge of the Sai, and this increased strength of the corrosive agent evidently accounted for the greater extent of the ground over which erosion had completed its work and produced flat depressions. One of these clay-bottomed depressions, crossed at about eight and a half miles' distance from camp, showed signs of having occasionally been flooded by drainage from the hill slopes northward. Varying flood levels were marked by lines of Toghrak trunks which may have been washed down from the slopes of Yardangs that have since completely disappeared. Here I came also upon a few specimens of those curious wind-driven balls of thorn, known as shag, which, apparently rootless, can keep alive on a minimum of atmospheric moisture. They may have been brought down from a higher level on the Kuruk-tâgh glacis.
The actual foot of this glacis, marked by a gravel Sai, was reached about a mile beyond the last-named depression and close to the point where Lai Singh's Camp 8o had stood. Above this to the north and only about two furlongs away, a few broad clay terraces of no great height emerge from the uniform gravel cover of the Sai, evidently ` witnesses ' of an older ground level which had escaped being buried by the deposit of piedmont gravel. On the top of one of these, Aziz, an
the topographical factors which, I believe, determined the route-line along the Kuruk-daryâ to the east of Ying-p`an ; cf. below, Chap. xxi. sec. iii.
17 See Serindia. i. pp. 394-40.5.