32 HISTORY OF SURVEYS [Chap. I
ground which the renewed visit rendered possible, proved the geographically interesting fact of a bifurcation taking place here in the waters of the Su-to-ho. While the river itself turns sharply westwards to terminate fully 180 miles beyond in the marshes flanking the westernmost section of the Limes, a small stream, fed by an inundation bed of the river below the oasis of Yü-men-hsien and also by subsoil drainage from the irrigation received from the Su-to-ho, flows to the east and ultimately is lost in a separate basin to. the north of the small oasis of Hua-hai-tzu or Ying-p`an. 37
It was along this stream and thus to the east that we discovered the continuation of the Limes line, instead of south-eastwards in the direction of Su-chou
Explorations in as I had been previously led to assume. The ground crossed by it had
Ying-p'an basin. remained so far unsurveyed, and the exploration of the ruins along it
was made increasingly difficult beyond by the distance which separated the long forgotten border from the nearest water. Nevertheless we succeeded in tracking it for some distance to the north-east of Ying-p`an before ultimately losing its line where it passed into an area covered by big dunes close to the barren foothills of the Pei-shan. 3s Thence we proceeded to the large town and oasis of Su-chou at the beginning of May in order to make preparations for our next move northward.
This journey led me down the united course of the rivers of Su-chou and Kan-chou into a portion of southernmost Mongolia offering geographical and
Ancient Limes traced 3 10, historical interest. Leaving Su-chou on May 10 I marched by a new
N. of Su-Chou. Leaving
route to the oasis of Chin-t`a, already visited in 1907. Following the Su-éhou river beyond, I succeeded in tracing afresh the line of the ancient Limes where it emerged on less impracticable ground near the south-eastern extremity of the Pei-shan. Thence we tracked it through to the north of the Mao-mei oasis, the last Chinese settlement. There Lâl Singh-rejoined me after having followed a hitherto unsurveyed route along the Kan-chou river where it breaks through the westernmost hill range of the Ala-shan. a9 As we moved down the Etsin-gol, as the united river is called by the Mongols, we found evidence that the ancient border line after crossing the river beyond Mao-mei had continued into the desert eastwards. But by the time of our return from the Etsin-gol delta in June the summer heat precluded its further exploration on this waterless ground.
The survey of the ground passed on the long trying marches along the Etsin-gol bed, then completely dry, proved of distinct geographical and also quasi-
ExploratioEtsin-gol n8 along historical interest. In a striking way it illustrated physical conditions
such as must have prevailed in the Lou-lan area Borth of Lop-new before its final desiccation. 4° While I was kept busy by fruitful excavations at the ruined town of Khara-khoto, first visited by Colonel Kozloff and identical with Marco Polo's ` City of Etzina,' and by explorations in its vicinity, Lal Singh carried out surveys right down the Etsin-gol delta to the two marshy lake-basins in which the river terminates. 41
On the conclusion of these tasks I let our hard-worked camels depart for their summer holiday in the Kungurche hills north-eastward. By sending Muhammad
Journey to Sao-t'ai Yaknb with them it became possible to map some hitherto unsurveyed
ground on the border of independent Mongolia. 42 I myself with Lal Singh turned southwards for fresh explorations in the Nan-shan ranges. From below Mao-mei we followed a route through hitherto unsurveyed portions of the desert hills to the east and north of the Kan-Chou river and after considerable fatigues due to heat and scarcity of water reached this near the town of Kao-t'ai. 43 From there I proceeded to Kan-chou by the main road in order to gain time, while Lal Singh after visiting a ruined site to the west of Kao-t'ai followed me by a new route along the right bank of the river.
38 See Sheets Nos. 42. 0, D. 4; 45. A. 4.
32 See Sheets Nos. 43. B-D. 1; 42. B-D. 4,
40 See Sheet Nos. 45. A. 3, B. 2, C. 1; cf. Third
Journey, G. J., xlviii. pp. 197 sq.
11 See Sheet Nos. 45. B, 0.1; 44. C, D. 4.
42 See Sheet Nos. 44. C. 4; 47. A, B. 2.
43 See Sheets Nos. 45. A.4; 46. A. 1, 2.