国立情報学研究所 - ディジタル・シルクロード・プロジェクト
『東洋文庫所蔵』貴重書デジタルアーカイブ

For the western and higher portion of this mountain rampart which rises to peaks of
over 23,000 feet, the Sheets Nos. 6, 9, 10, 14, 15 afford ample cartographical materials. To
the east of the Keriya river the character of the chain overlooking the Tārim basin does not
change; but its width is reduced and the elevated Tibetan plateaus approach it closer from the
south. Throughout the whole length of the chain the foot of its northern slopes is formed by
a glacis of piedmont gravel, attaining in parts a width of 40 miles and more, and everywhere
utterly sterile.

On the north the basin of the Tārim is enclosed by the great T'ien-shan chain. In the
west it meets the meridional range above mentioned near the Alai and the
T'ien-shan range. headwaters of the Kāshgar river. Thence it stretches away unbroken to
its north-easternmost corner near Korla where the Konche-daryā, fed by
the Baghrash lake, enters the plains (Sheets No. 24, 25). North of Ak-su, the T'ien-shan
attains its culminating point in the great peak of Tengri-khān (Sheet No. 11). Thence
eastwards a branch of the main chain, gradually diminishing in height, forms the enclosing
wall of the basin. To the west of Ak-su a series of outlying lower ranges intervenes between
the main chain and the plains (Sheets No. 4, 5, 7).

While our surveys show this portion of the northern rim in some detail, east of Ak-su
they were confined mainly to the southern slopes of the range immediately overlooking the
basin (Sheets No. 16, 17, 20, 21). Nevertheless they suffice to bring out certain characteristic
differences between this northern mountain border and the K'un-lun. Among them I may
mention the much smaller width, or complete absence, of the gravel glacis at the foot of the
T'ien-shan, and the less arid character of the main range as demonstrated by the presence of
conifer forest in a number of valleys on its southern slopes. ¹ Both these facts bear evidence
to the influence asserted by the far moister climatic conditions which prevail north of the
T'ien-shan.

Beyond Korla the desert uplands of the Kuruk-tāgh, the 'Dry Mountains', take the
place of the T'ien-shan as the border of the Tārim basin both to the
Desert ranges of
Kuruk-tāgh. north and north-east. The character of this barren succession of much-
decayed parallel ranges with wide gravel-filled valleys and drainageless
basins between them, is adequately illustrated by the surveys embodied in Sheets No. 25, 28,
29, 32. What scanty moisture ever reaches the southern slopes of the Kuruk-tāgh and
escapes evaporation on its wide gravel glacis, descends in wide flood-beds to the Konche-daryā
and its ancient continuation eastwards, the Kuruk-daryā or 'Dry River', which once carried its
waters to the Lou-lan area. The aridity of the Kuruk-tāgh steadily increases eastwards until
at about longitude 91° even the rare salt springs, which rendered its exploration possible, are
no longer encountered.


Section II.—THE TAKLAMAKAN DESERT.

Within the Tārim basin enclosed by the mountain barriers briefly described above,
we may conveniently distinguish four main regions. By far the
Central desert of
drift-sand. largest, and perhaps the best defined, comprises the huge central area
of bare drift-sand desert, popularly known as the Taklamakān. Its
borders to the west, north, and east are roughly determined by the belts of vegetation
accompanying the Tiznaf, the Yārkand and the Tārim rivers, the last being the name
generally given to the Yārkand-daryā after receiving the rivers of Kāshgar, Ak-su and
Khotan. The dune-covered area has outliers beyond these riverine borders in a number of
places. But only two of these, both at the extreme ends of the central area, are sufficiently
large to deserve here special mention. In the west we have the moving sands of Ordam-
pādshāh stretching from the vicinity of Yangi-hissār to the left bank of the Yārkand river