Sec. i] HISTORICAL TOPOGRAPHY OF KARA-SHAHR 1179
the middle of the latter, and which the Tarim traverses along its whole length from east to west, it sends all its ,drainage towards the Tarim delta and yet forms a distinct basin by itself. This Kara-shahr basin, as any general map shows, is enclosed on the north by a range of the central Tien-shin system which stretches from the western rim of the Turfan depression west towards the Yulduz plateaus. On the east and south it is framed round by barren hill ranges of the Kuruk-tagh. In the west these link on to that southernmost Tien-shan range which edges the riverine flat of the Tarim from Korla towards Kucha. Between the foot of this range and the westernmost offshoot of the Kuruk-tagh lies the narrow defile above the Korla oasis in which the river draining the lake of Kara-shahr, or the Baghrash-köl, breaks through to the plains of the Tarim.
The great lake forms the chief and most characteristic feature of the Kara-shahr basin. With its marshy edges it extends, according to Roborovsky's reliable surveys, for a distance of over 50 miles from east to west with a maximum width of about 3o miles. It is nowhere of great depth, but holds fresh water for the greatest portion of its area and abounds in fish. Its water is supplied mainly by the Khaidu-gol, a considerable river which drains the Yulduz plateaus and the high Tien-shan ranges around them. The volume of this is increased above Kara-shahr by an affluent from the north which drains distant snowy mountains between Kara-shahr and Urumchi.8 The valley of the Khaidu-gol is of great width for a distance of over 6o miles above the town of Karashahr and forms an important extension of the basin north-westwards.
It is the abundance of water which is, perhaps, the most distinctive feature of the district. This is sufficiently indicated by the great area covered by its freshwater lake and by the large and practically permanent volume of water which the lake discharges in the Konche-darya flowing through the defile above Korla.° As far as my olservations go, there is no area of corresponding size in the Tarim Basin which commands a water-supply so abundant and so easy to utilize for irrigation. To this advantage is added a climate which, judging from a variety of .observations, including personal experience during my stay at the site north of Shörchuk, appears to be appreciably moister than that of the oases along the northern edge of the Tarim Basin or to the south of the Taklamakan. The conditions here briefly indicated are reflected in a striking manner by the great belt of vegetation excellently suited for winter grazing which encircles the Baghrash Lake almost everywhere,'° and extends on all sides close to the foot of the mountains.
With conditions so favourable for cultivation, and with the great extent of ground which canals from the Kara-shahr River could command in the north-western portion of the basin, the very limited number and size of permanent settlements to be found at present in the district contrast in a fashion which is bound to attract attention. Wherever I moved in the Kara-shahr basin, I was struck by the disproportion between the scanty area of cultivation, which was, too, mostly neglected, and the great extent of arable land awaiting occupation. It was easy to realize the connexion between this state of things and the strangely mixed nature of the population. It consists in the main of Mongols who have only recently taken to agriculture and still continue to lead a semi-nomadic existence at the same time ; of Chinese settlers introduced since the reconquest ; of Tungan colonies forcibly planted here still more recently, and a very slight admixture of Turki Muham-
8 The debouchure of this affluent of the Khaidu-gol is shown in Roborovsky's Map II in a position approximately corresponding to the valley marked in 11Iap No. 48. A. 2, between the clinometrically fixed heights 12391 and s 1211. The valley was sighted by R. B. Lai Singh from a great distance. Hence its continuation northward, formed by a deep-cut winding gorge, remained unnoticed and has not been correctly indicated in our map.
' Cf. Hedin, Reisen in Zenlral-Aslen, p. 68, where the volume of the river, even after the not inconsiderable loss due to canals taking off above Korla town on either side of the river, is estimated at about 72 cubic metres per second.
10 For this belt of luxuriant reed-beds, scrub, and Toghrak jungle, north of the lake, see Maps Nos. 48, 51. A survey of 5915 showed it also along the south shore, though in lesser width.