The survey within the portion of the K'un-lun represented in this sheet was made during August and September, 1907, only the westernmost snowy peaks, including 'Muz-tagh' (Pk. 1/61A) and those on the northern main K'un-lun range (A-D. 1), having been sighted in 1900-01. The plane-table work was based on a great number of previously triangulated peaks which are
shown in Appendix A (61 A, 61E). Of
these five were fixed by the Kashmir triangulation of the G. T. Survey (Johnson, 1862). ,of other trigonometrical points most were determined by Captain Deasy, while some are derived from triangulation work of my first and second journeys.
An account has been given above of the routes by which the survey was first carried to the very difficult ground at the headwaters of the Yurung-kâsh river and subsequently extended past the basin of the Keriya river sources (D. 2) to the high and barren plateaus stretching along the southern range of the K'un-lun (see pp. 21 sqq.). Observations made in different parts of these ranges indicated an approximate snow-line at levels varying from about 17,500 to 18,500 feet.
For a fairly detailed description of the routes followed in this rugged mountain region and on the plateaus to the south, see Desert Cathay, ii. pp. 443 sqq., Figs. 318332. The only track through it, occasionally
NOTES ON SHEET No.
The small area at the foot of the T`ienshan, shown in this sheet, was surveyed from a single route and by R. B. Lai Singh alone towards the end of April, 1915. The early season and adverse atmospheric conditions prevented extension of his work further towards the main range. The watershed of this appears to have been nowhere within view, and on various grounds it is probable that the headwaters of both the Kizil and Kuchâ rivers reach considerably further north than conjecturally indicated on the plane-table.
used, leads from Polur to Ladak over the Baba-Ilâtim and Lanak-la passes. Its difficulties are great, and, though, no doubt, known since early times, it cannot be traced in old records.
Among the physical features of this elevated region the most striking, perhaps, is the great contrast between the extremely deep-cut, and in many places quite inaccessible, gorges of the Yurung-knish headwaters and the wide, in parts ice-clad, basins in which rather the sources of this and the Keriya river. Quite different, too, from the former is the character of the forbiddingly barren uplands of northernmost Tibet which lie south of the southern main range and extend also between the Keriya river drainage and the northern chain.
As the Yurung-k:ish gorges west and south of the great and conspicuous massif of `Muz-tagh' (Pk. 1/61 A), and probably those below the Zailik valley debouchure (B. 1) also, are quite impassable, access to that portion of the upper Yurung-kâsh drainage which the map shows as wholly unexplored will have to be sought by some glacier pass across the northern range from the Genju or Ulùgh-sai headwaters (No. 14. B. 4) .
Correction. The contours and cliff symbols along the Yurung-kâsh river course below Zailik (A, B. 1) should throughout be brought close to the left bank.
16 (KERE-BAZAR, BAI)
The traverse was fitted to the position adopted for Kuchâ (see below), and details adjusted to the latitude observed at Karakul (B. 4) and to the route lines KuchaMuz-art pass and Kuchâ—Korla.
The surveyor's observation of conifer forest on the southern slopes of the range at elevations from about 7000 to 9000 feet is fully borne out by Dr. Merzbacher's observations in the Terek valley north-west of Bai, and in other Tien-shan valleys further west ; cf. Merzbacher, The Central Tianshan (London, 1905) pp. 133 sq., 141, etc.