Chap. IV] NOTES ON SHEET No. 12 73
wells makes it possible tq pass through it direct from Kuchà to Ak-su by an old but now little frequented track (B-D. 2). South of the Tàrïm extends the dune-covered Taklamakàn, interrupted only by the delta
through which for a brief period of the year the summer floods of the Khotan-daryà effect their junction with the former. For changes in this delta, cf. Serindia, iii. p. 1296; Geograph. Journal, xlviii. p. 114.
Astronomically observed latitude.
1913-15. Kök-yàr, Kara-bàgh, C. 330 (Beg's house; B. 1) ... ...• 400 49' 13"
NOTES ON SHEET No. 13 (MAZAR-TAGH, KARA-DONG)
been adjusted to the positions adopted for Kuchà and Kochkar-öghil (see Notes on Sheets 11, 17).
For descriptive accounts of the Khotan river route, see Desert Cathay, ii. pp. 417 sqq., and of the Keriya river route, Ruins of Khotan, pp. 405 sqq. Some observations on the historical topography of the routes are recorded in Ancient Khotan, i. pp. 449 sq; Serindia, iii. 1240 sq., 1291. As regards the character and connectibn of the wind-eroded hill range of which the Mazàr-tàgh on the Khotan river forms the easternmost traceable remnant, see above pp. 20,28.
The surveys shown by this sheet are confined to the terminal courses of the Khotan and Keriya rivers passing through the Taklamakàn. The route along the former was followed both on the second and third expeditions, that along the latter on the first and second. The former traverse, which owing to its north-south direction was well controlled by latitude observations, was adjusted in longitude to the positions accepted for Khotan and the Tarim—Ak-su river junction (see Noies on Sheets No. 9, 12). The Keriya river route, for which similarly several observed latitudes could be used, has
Astronomically observed latitudes.
1900-01. Kara-dong, Camp III (N.W. corner of ancient fort; D. 3) ..
1906-09. Malghun, Camp 367 (A. 4) ... ...
Mazàr-tàgh, Camp 369 (on left river bank, cire. 1/2 mile N.E. of
ruined fort, B. 4) ..
Ayak-üstang-aghzi, Camp 371 (B. 2 ), (by Polaris)
(by Sun's meridional altitude) ...
38° 32' 39"
38° 3' 5"
38° 27' 12T
39° 0' 1'
39° 0' 4"
NOTES ON SHEET No. 14 (SAMPULA, CHIRA, KERIYA)
This sheet comprises much varied and interesting ground between the rivers of Khotan and Keriya and extending from the northernmost limit of ancient cultivation to the snowy spurs of the main K'un-lun range. It has been compiled from numerous surveys on all three journeys, and is crossed in the middle by the old caravan road which connects the oases along the southern edge' of the Taklamakàn. The exploration of a large series of ancient sites now abandoned to the desert accounts for the network of surveys to the north of that road, while in the south most of the routes were followed in connection with the triangulation work along the K'un-lun.
The numerous points fixed in the course of this work and by Captain Deasy's triangulation (see Appendix A), together with the conspicuous G.T. Peak 3/60D (Tikelik-tàgh), furnished an adequate basis for both plane-table work and cartographical construction
in the southern portion of the sheet. For the main road from Khotan to Keriya, a series of latitude observations were available, while longitudes could be determined with fair accuracy by interpolation of the results of three separate plane-table traverses between the accepted position of K hotan and that of Niya, fixed by triangulation (see Notes on Sheet No. 19).
On the route leading northwards along the Keriya river, the longitude of Kochkaröghil was derived from the concordant results of interpolation between Keriya and Kuchà and between Khotan and Domokobàzàr via Dandàn-oilik. The routes along the Yurung-kàsh and Kara-lash rivers are adjusted, as in Sheet No. 13, to the longitudes accepted for Khotan and the TarïmAk-su river junction. The snow-line has been conjecturally assumed at an elevation of about 16,500 feet, in conformity with that observed in Sheet No. 15.