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

of the Mazār-tāgh, whence it irrigates the fields of Chār-bāgh. Less than a mile from where we
camped by the river bank we crossed a canal, known as Kodai-daryā, which during the flood season
of the river carries water to the Chaghān-köl marsh SW. of Tumshuk ; this in turn serving as
a natural reservoir for the irrigation canals of villages farther east.

On the morning of October 26th we crossed the river at a ford where the single bed actually Ford across
holding water was about 55 yards wide with a maximum depth of 4 feet, the velocity of the current Yārkand
being only about 1·7 foot per second. The flood bed (Fig. 81) was nearly a mile wide, and some river.
idea of the huge volume of water that passes down at the height of the summer floods could be formed
from the statement of our guide, a local hunter called Aziz (Fig. 86), that during about a month
the water then overflows the steep clay bank, some 16 feet high, which bounds this flood bed on
the south. All the day's march led through rich grazing, mostly of reed-beds, and luxuriant
young jungle. The autumn tints of the belt of vegetation contrasted vividly with the dark brown
and red of the desolate hill chains of the Mazār-tāgh to the north and the much lower Kum-tāgh
to the south. The latter, which appeared nowhere to rise more than about a thousand feet above
the riverine flat, was seen to have its south-west and north slopes overlaid by huge accumulations
of dunes (Fig. 82) very similar to those that we had observed on the Bēl-tāgh.⁵

That the Kum-tāgh, as it is appropriately known in consequence, represents a direct continua- Defile
tion of the Mazār-tāgh is shown by the map (No. 8. B. 1) ; and this is confirmed by the prevalence between
in the rocks of the Mazār-tāgh of the same calcareous sandstone containing feldspar and permeated Kum-tāgh
by thin porphyrite strata that constitute the main formation of the Kum-tāgh, as indicated by and Mazār-
Dr. Hedin's specimens and my own.⁶ The defile through which the Yārkand-daryā passes between tāgh.
the two hill chains proved to be only about five miles wide. It presents a very striking feature in
the river's course, which everywhere else, from the point where it debouches above Yārkand right
down to its termination in the Lop-nōr marshes, passes solely across level plains of alluvium and
drift-sand. I shall have occasion below to touch upon the question of the genetic relation which
may be surmised to exist between the river course at this point and the survival by its side of the
highest among the island-like hills that form part of the ancient diagonal range.

We camped near fine groves of Toghraks growing amidst reed-beds and low dunes to the Lake be-
north of the Kum-tāgh. This is faced on the east by a bolder and higher hill range, running in tween Kum-
a parallel direction, approximately NW.–SE., and extending from the Yārkand river for a distance tāgh and
of over twelve miles. It is known to the Dolāns of Marāl-bāshi by the name of Chok-tāgh. The Chok-tāgh.
depression between the two hill chains, about four miles across at its widest, is filled for the greater
part by a far-stretching lake, filled annually by the inundation of the river and known as Chöl-köl,
the ' desert lake '. Its southernmost end was to serve as the starting-point for our desert venture,
just at it had for that of Dr. Hedin. To reach it we, like him, found it best to proceed by the level
and open stretch of ground that divides the west shore from the foot of the Kum-tāgh. After
crossing, not without some trouble, a series of depressions in which water remained from the last
summer flood, we skirted the sandy glacis of an extreme north-eastern offshoot of the Kum-tāgh.
It was of interest here to note that the surface consisted of small flakes of completely decayed rock
debris, dark red and of slaty appearance, forming a thin layer over fairly fine sand. The steady
deflation and corrosion that is grinding away these remnants of the ancient mountain range could
not find a better illustration.

Ever since leaving the river we had been following a well-marked cart track, and after skirting Salt-digging
the reed-beds that fringe the lake shore we came to a low but steep ridge jutting out from the above W.
foot of the Kum-tāgh. It was found to consist of detritus of a reddish rock, a hard silicious shore of
lake.