up to the mountains on both north and south. Its surface slopes from
altitudes of 10,100 to 10,600 ft. in the west, where is the lake of Uzunshor
(9650 ft.) to 9400 ft. in the east, in which direction it continues
as far as the Anambaruin-ula (see below) and the plain or flat basin
of Särtäng, a north extension of Tsaidam. This range of Akato-tagh,
the Altun Range of Carey, is the same as that which on the map of
the Russian general staff bears the name Chimen-tagh. Like the
Astin-tagh it stretches towards the E.N.E., and, like it, appears to
be built up of granite and schists, but its crest is greatly denuded,
so that it is a mere crumbling skeleton protruding above the deep
mantle of disintegrated material which masks its flanks. The slopes
on both north and south are extremely gentle, but that on the south
is eight to ten times as long as that on the north. In the east the range
is mostly narrow, and dies away on the edge of the Tsaidam depression;
but in the west it swells out into the lofty and imposing mass of
the Ilve-chimen or Shia-manglay, which is capped with perpetual
snow. This part of the range is crossed by the pass of Chopur-alik
at an altitude of 16,160 ft., but farther east the passes lie at altitudes
of 13,380 to 10,520 ft. The latitudinal valley that intervenes
between the Akato-tagh and the next great range on the south, the
Chimen-tagh, slopes for the most part eastwards, from 12,500 ft. down
to the shallow salt lake of Ghaz-kol or Chimen-koli (9305 ft.). In
the western part of this valley occurs the very important transverse
water-divide of Gulcha-davan (14,150 ft.), which separates the basin
of the Cherchen-darya that goes down into the Tarim basin from the
area that drains down to the Ghaz-kol, which belongs to the Tsaidam
depression. This, the Chimen valley, contains in places a good deal
of drift-sand, which however is stationary in the mass and heaped
up along the northern foot of the Chimen-tagh. Nevertheless the
Akato-tagh is only of secondary importance in the general Kuen-lun
system, being nothing more than a central ridge running along the
broad Kakir valley that separates the Astin-tagh from the Chimen-tagh.
The latter range, the Chimen-tagh, is identical in its western parts with the Piazlik-tagh and in the east must be equated with the Tsaidam chain of Przhevalsky; and it is probably continued westwards by the range which the Russian explorers call the Moscow Range or the Achik-tagh, running north of the Achik-kol and, according to Przhevalsky, connecting on the west with the Tokuz-davan. The Chimen-tagh rises into imposing summits, some rounded, some pyramidal in outline, which are capped with snow, though the snow melts in summer. This range acts as a “breakwater” to the clouds, arresting and condensing the moisture which is carried northwards by the south winds. Hence its slopes are not so arid as those of the Akato-tagh and the Astin-tagh. Snow falls all the year round on the Chimen-tagh, even in July, and water is abundant everywhere. The southern slope of the range is gentle but short, the northern slope long and steep. Grass is able to grow, and animal life is more abundant. The range is crossed by passes at 13,970, 13,230 and 13,760 ft., and the Piazlik-tagh by a pass at an altitude of 13,640 ft.
The next important range, still going south, is the Kalta-alaghan, Carey’s Chimen-tagh Range, Przhevalsky’s Columbus Range and the range which is variously designated (e.g. by Pyevtsov) as the Ambal-ashkan, Kalga-lagan and Ara-tagh. This last is, however, properly the name of a short secondary range which rises along the middle (ara = middle) of the valley between the Chimen-tagh and the Kalta-alaghan. Not only is it of lower elevation than them both, but it dies away towards the west, the valleys on each side of it meeting round its extremity to form one broad, open valley, with an altitude of 11,790 to 13,725 ft. The Ara-tagh is crossed by a pass at an altitude of 14,345 ft. In the Kalta-alaghan, which is the culminating range of this part of the Kuen-lun, and is overtopped by towering, snow-clad peaks, the passes climb to considerably higher altitudes, namely, 14,560, 14,470, 14,430 and 14,190 ft., while the pass of Avraz-davan ascends to 15,700 ft. This range appears to be linked on to the Tokuz-davan by the Muzluk-tagh, in which there are passes at 16,870 and 15,450 ft. It is possible however that the Muzluk-tagh belongs more intimately to the Chimen-tagh system, that is, to the Moscow or Achik-kol ranges, Indeed Bogdanovich considers that the Tokuz-davan, the Muzluk-tagh, the Moscow Range and the Chimen-tagh form one single closely connected chain, in which he also places Przhevalsky’s isolated peak of Mount Kreml (15,055 ft.). Sven Hedin, whilst agreeing that this may possibly be the true conception, inclines to the view that the Achik-kol Range dies away towards the E., and that the Chimen-tagh and the Kalta-alaghan merge westwards into the border-ranges that lie north of the Muzluk-tagh and the Tokuz-davan. Unlike most of the other parallel ranges of N. Tibet, the Kalta-alaghan does not decrease, but it increases in elevation towards the east, where, like the Chimen-tagh, it abuts upon and merges in the ranges that border Tsaidam on the south.
Immediately south of the Kalta-alaghan comes a relatively deep depression, the Kum-kol valley, forming a very well-marked feature in the physical conformation of this region. It is crossed transversely by a water-divide which separates the basin of the twin-lakes of Kum-kol (12,700 ft.) from the basin of Tsaidam, some 3500 ft. lower. The floor of the valley consequently slopes away in both directions, like the Chimen valley between the Akato-tagh and the Chimen-tagh; and in so far as it slopes westwards towards the Kum-kol lakes it differs from nearly all the other great latitudinal valleys that run parallel with it, because they slope generally towards the east. Not far from the Kum-kol lakes there is a drift-sand area, though the dunes are stationary. The upper lake of Kum-kol (Chon-kum-kol) (12,730 ft.), which contains fresh water, is of small area (8 sq. m.) and in depth nowhere exceeds 13 ft.; but the lower lake (Ayak-kum-kol) (12,685 ft.), which is salt, is much bigger (283 sq. m.) and goes down to depths of 64 and 79 ft. Farther west, lying between the Muzluk-tagh and the Arka-tagh, is the lake of Achik-kol (13,940 ft.), 1612 m. broad and 50 m. in circuit.
The next great parallel range is the lofty and imposing Arka-tagh, the Przhevalsky Range of the Russian geographers, which has its eastward continuations in the Marco Polo Range (general altitude 15,750–16,250 ft.) and Gurbu-naiji Mountains of Przhevalsky. The Arka-tagh[1] is the true backbone of the Kuen-lun system, and in Central Asia is exceeded in elevation only by the Tang-la, a long way farther south, this last being probably an eastern wing of the Karakorum Mountains of the Pamirs region. At the same time the Arka-tagh is the actual border-range of the Tibetan plateau properly so-called; to the south of it none of the long succession of lofty parallel ranges which ridge the Tibetan highlands seems to have any connexion with the Kuen-lun system. Of great length, the Arka-tagh, which is a mountain-system rather than a range, varies greatly in configuration in different parts, sometimes exhibiting a sharply defined main crest, with several lower flanking ranges, and sometimes consisting of numerous parallel crests of nearly uniform altitude. Amongst these it is possible to distinguish in the middle of the system four predominant ranges, of which the second from the north is probably the principal range, though the fourth is the highest. The passes across the first range (north) lie at altitudes of 15,675, 16,420, 17,320 and 18,300 ft.; across the second at 16,830, 17,020, 17,070 and 17,220 ft.; across the third at 16,800, 16,660, 17,065, 17,830 and 17,880 ft.; and across the fourth at 16,540, 16,765, 16,780, 18,100 and 18,110 ft. The crests of the ranges lie comparatively little higher than the valleys which separate them, the altitudes in the latter running at 14,940 to 16,700 ft., if not higher, and being only 500 to 1000 ft. lower than the crests of the accompanying ranges. The Arka-tagh ranges do not culminate in lofty jagged, pinnacled peaks, but in broad rounded, flattened domes, a characteristic feature of the system throughout. These Arka-tagh mountains are built up, at all events superficially, of sand and powdery, finely sifted disintegrated material. Where the hard rock does crop out on the surface, it is so excessively weathered as to be with difficulty recognized as rock at all. The culminating summits of the ranges generally present the appearance of a flat, rounded swelling, and when they are crowned with glaciers, as many of them are, these shape themselves into what may be described as a mantle, a breast-plate, or a flat cap, from which lappets and fringes project at intervals; nowhere do there exist any of the long, narrow, winding glacier tongues which are so characteristic of the Alps of Europe. But not the slightest indication has been discovered that these mountains were ever panoplied with ice. The process of disintegration and levelling down has reached such an advanced stage that, if ever there did exist evidences of former glaciation, they have now become entirely obliterated, even to the complete pulverization of the erratic blocks, supposing there were any. The view that meets the eye southwards from the heights of the Kalta-alaghan is the picture of a chaos of mountain chains, ridges, crests, peaks, spurs, detached masses, in fact, montane conformations of every possible description and in every possible arrangement. Immediately north of the Arka-tagh the country is studded with three or four exceptionally conspicuous and imposing detached mountain masses, all capped with snow and some of them carrying small glaciers. Amongst them are Shapka Monomakha or the Monk’s Cap; the Chulak-akkan, which may however be only Shapka Monomakha seen from a different point of view; Tömürlik-tagh[2] (i.e. the Iron Mountain); and farther west, Ullugh-muz-tagh, which, according to Grenard, reaches an altitude of 24,140 ft. But the relations in which these detached mountain-masses stand to one another and to the Arka-tagh behind them have not yet been elucidated. In the vicinity of the Ullugh-muz-tagh there exist numerous indications of former volcanic activity, the eminences and summits frequently being capped with tuff, and smaller fragments of tuff are scattered over other parts of the Arka-tagh ranges.
The next succeeding parallel range, the Koko-shili, which is continued eastwards by the Bayan-khara-ula, between the upper headstreams of the Hwang-ho or Yellow River and the Yangtsze-kiang, belongs orographically to the plateau of Tibet.
The succession of ranges which follow one another from the deserts of Takla-makan and Gobi up to the plateau proper of Tibet rise in steps or terraces, each range being higher than the range to the north of it and lower than the range to the south of it. The difference in altitude between the lowest, most northerly range, the Lower Astin-tagh, and the most southerly of the Arka-tagh ranges amounts to nearly 7500 ft. With one exception, namely the climb out of the Kum-kol valley to the Arka-tagh, the first three steps are
