1923%20Memoir%20on%20Maps%20of%20Chinese%20Turkistan%20by%20Stein%20s

Sec. iv.] THE LOP DEPlCESSION AND TURFAN BASIN 49
the importance of the territory already in ancient times in amply attested by archieological
remains and liistorical recortls allke. If we coinr,arc this fact with tile great extent of tllat
of the cultivated area which now, as the map nllows, depcrlds solely on Kiri.2 irrixation,
the progress made by desireation in this region receives striking illucjtration.
SECTION V.--THE SU-LO-HO BASIN
East ol' the Lop depression our surveys extended to a series of drainagelesn regions
which, if not eon~parable in size to the l'drim basin, .set resemble it
lrtcnt of Su-lo-ho
bns~n.
t losely in various physical features of importance and are linked up
wit11 it a.lso in historical interest. Proceedinz from the extreme eastern
end of tlie Lop depression across a dry lake-bed once apparently draininz into it., 1 we enter
directly the lowest portion of the basin of the Su-lo-110, containing this riser's delta and
terminal nmrsl~cs. This basin, as sl~own on Slicets Kos. 35, 38, 10, extends for wme 220
miles from east to mest with an average nitlfh of 30-40 miles betnren the fcot hills oi the
ranges tvlricl~ bound it.
Pei-slran nortliwartl.
These are the w~stern Nan-shau in the south and the utterly barren
The Su-10-110, a considrrable river, fed hy glaciers and eternal snows of the
Central Nan-khan, dcscends into the basin at its eastern end. After
course of SU-lo ho. 1)reakilig t,hrough n succession of ranpes in gol.ges, of which those to
the south are as yet unexplored, it ski1.t~ a low divide serarating its
basin from one much smaller adjoining eastwards. Below the oasis of Yii-min-bsien the
Su-10-110 turns sharply \vestmards. Maintaining this course it lasses fhrcugh the Khara-n6r
lake, s~~p~osed to be its terminal basin until our surveys proved this to Ee situated some 80
miles further west in tlie salt marshes already referred to. * On its whole course through the
basin tlie Se-lo-ho receives only one affluent, the Tang-ho or Tun-huang river, rising on high
plateaus towards Tsaidam. This provides ample irrigation for the large oasis of Tun-huang,
or Sha-ehou, which occupies its alluvial fan.
Tun-huang is the only settlement of considerable size in the whole region, and its local
resources were of special value in ancient times when the great natural
Importnnce of 'run
huang onsls.
passage of the Su-lo-ho basin served as the earliest high road of Chinese
expansion into Central Asia. It was for the protection of this importc
ant trade-route leading through LOU-Ian to the oases of the Tarim basin that the far-flung
westernmost portion of the ancient Chinese border line was constructed towards the second
century B. c. The extreme aridity of the desert ground, over which it led past the Su-lo-ho
and its riverine marshes, explains the abundance and remarkable preservation of the ancient
records, etc., brought to light by my explorations along this ruined firnes.
Excepting the narrow belt of desert vegetation which accompnnies the river's lower
course and the limited ground capable of irrigation besido the oa.sis of
1)eaert featllrrs of
bnsiu.
Tun-huang, the Su-10-110 basin consists mainly of slopes of absolutely
bare gravel, corresponding to the ' Sai ' of the K'on-lun. Immediately
south of Tun-huang, hotsever, and again beyond the small oasis of Nan-hu in the south-west,
huge accumulations of drift-sand al~proach or overlie the foot-hills of the Nan-shan. 7 These
have been heaped up by the violent east and north-east winds whicll for a grcat rart of the
year blow down into the basin from the plateaus of the Pei-shan,-another case of 'aspiration'.
1 See above p. 31. the ancient Chinese Limes nlong the Su-lo-ho basin,
See Sheet No. 36. 8, C. 4. as elncid~tcd by rnp explorations of 1907. are suma
See hheet Yo. 41. 0. 1, C. 1-3. marized in Clbapter XX nl SwindLr. ii. pp. 72'! sqq.
4 See Sheets No. 36. 13-D. 4; 38. A. 4. 7 See Sheets h'o. 36. C. D. 1 ; 38. R. 4: 31). .I, t).
Cf. Setindin, ii. pp 678 sqq r~n the 'Geogrpbi.
featnreR of the lower hn-lo-110 basin '.
The main facts co~tcerning this extension of
1 ; see also No. 86. R. 4 fnr the big sand ridges sklrting
the terminal bed of the So-lo-ho.