station ; but only the base had remained to a height of 2 or 3 feet, together with such refuse as the floor of a small room placed on it had retained. Evidently the watch-post was of the type illustrated by T. XXIII. a or T. xxIII. g, consisting of a small room placed in a commanding position.15 Among the miscellaneous refuse was found the wooden spindle, T. xLI. e. 02 (Pl. XLVII), and just outside the fascines an inscribed Wu-chu coin of the large type.
The track skirting the foot of the low ridge, where it abuts on the river-bed, brought us, a mile farther on, to a big tower, T. xLI. f. It was perched conspicuously on the top of a detached hillock, rising about 150 feet above the riverine flat. The tower with its loop-holed parapet looked decidedly modern, but closer examination soon showed that an ancient tower of Han type had been enlarged on the east, south, and west by a facing of late masonry. In this the bricks were set on end, after the fashion prevailing in modern structures of Kan-su. The original tower was solidly built of bricks measuring 15 inches by Io and 4 inches thick and with reed layers between the courses at intervals of 3 feet 6 inches. Its base measured 24 feet square. The addition of later masonry, with bricks 14 x 6 x 3 inches, had increased this to 32 feet. The present height is 32 feet. The southern face showed very clearly the arrangement of foot-holes by which to reach the top. The tower commands a distant view along the river both to the east and west.
At first only slight refuse was found covering the rocky soil at the southern foot of the tower. But search on the stone-covered slope soon showed that rubbish lay concealed on that side down to about 20 feet below the base and to a depth of about 2 feet. On rapidly clearing this, the miscellaneous relics described in the List below were brought to light amidst refuse of straw, chips of wood, & c. They include a number of wooden writing slips, blank or effaced ; the fragment of a writing tablet, made of the wood of some conifer, T. xm. f. oI ; numerous small pieces of plain textiles of silk and what appears to be cotton, & c. No doubt all small objects thrown down here by those who occupied this watch-post had suffered to some extent by the drainage from occasional rain and snow. Yet one wooden slip, broken into three pieces, T. xLI. f. 026, still retained its writing in Chinese characters of Han ductus [mentioning the officer in charge of a watch-tower]. A Chinese coin found here, bearing traces of the inscription Huo-ch`zian, also attests occupation in Han times. Two copper coins of the Manchu period which were discovered near the tower had obviously been left by men who had kept guard there in recent times.
A small enclosure of stamped clay, T. XLI. g, standing at the foot of the hillock, had a much more recent appearance. The numerous fragments of glazed ware and of porcelain found within and near by were in harmony with this, and likewise a coin apparently of the K`ang-hsi period.16 We had skirted the foot of the ridge for only a quarter of a mile beyond when I noticed layers of tamarisk brushwood cropping out on the stony slope. They obviously marked a much-decayed segment of the Limes agger. It was traceable here for about 40 yards, running parallel to the river, and reappeared for another short stretch close to the river less than half a mile farther on.
Then all trace of the border line was lost on a desolate belt of bare clay intervening between the river and the foot of the gravel Sai. It showed signs of far-advanced wind-erosion, Mesas up to 20 feet in height rising here and there among smaller Yârdang-like terraces. We had moved thus for about six miles eastwards without coming upon any sign of wall or towers when, on passing into a gravel-covered Sai, a long straight line on our left rising above the level ground attracted our Mongol's attention. On reaching it, about a mile away from the river, it revealed itself by the brushwood cropping out on the sides of the low mound as a much-decayed stretch of the Limes agger. Close to where we had struck its line the remains of a completely ruined tower marked the position of a watch-station, T. xm. h. From the scanty refuse near it we recovered two wooden slips, as used for Chinese records, but effaced.
15 See Serindia, ii. p. 721 ; above, p. 351. 16 For specimens of this ware, see the Descriptive List
below, pp. 42o sq.