BACK TO THE ARKA-TAGH. 165
same altitude as the pass in the last preceding range, namely 5203 m., but this steep portion is so short that it presented no real difficulty. The descent down the northern face is very much steeper; in fact it plunges straight down into a deep glen or gorge. In some places the outcrops of the rocks quite made steps. The small torrents from this and the neighbouring pass gather into a larger glen, relatively wide and open, though absolutely barren, and with a frozen stream down the middle of it. This pass put me forcibly in mind of the pass in the Arka-tagh which I crossed over in this same neighbourhood in 1896. In its case too the southern acclivity was easy and gentle, but the northern steep and difficult. The orographical structure of these more western parts of the Arka-tagh is very much simpler than it is in the parts where we crossed over it south of Kum-köl, for in the latter quarter the range is split up into several parallel crests.
The predominating rock all day was a green schist, the dip of which varied from 14° towards the N. 5° E., 86° towards the N. 40° E., and 35° towards the S. 15° W. to 29° towards the S. 20° W. on the pass itself, while north of the pass it was 25° S. The predominant lie of the rocks in this part of the Arka-tagh may be taken as 35° to the S. 15° W.
On the south side of the range the wind blew from the south-west; but on its summit it changed to north-north-east, and brought with it thick, blinding snow. Here again the Arka-tagh appeared to serve as a climatic dividing-line, though, I admit, not a very rigid line. North of it the cold is generally severer, while the precipitation, especially on the northern slope of the mountains, is heavier than on the south, where the great Tibetan plateau extends far and wide, and the winds too are different.
October I st. Just below Camp LXII (alt. 4977 m.) our glen united with a second similar glen coming from the east, and like it having its origin in the main chain of the Arka-tagh. The united glen then inclines towards the north-west, and, increasing in breadth, terminates in a wide expansion, an open arena or cauldron-shaped valley, upon which several glens debouch from different directions. On the south it is embraced between short spurs thrust straight out from the Arka-tagh. Farther to the west there are lofty snowy mountains. On the east the open arena just spoken of is bordered by a great spur from the main range, and on the north by a more independent range. In the eastern part of the glen the grazing and japkak were pretty good. The brook was frozen so hard that it even bore the weight of the camels. Camp LXIII had an altitude of 4899 m.
At Camp LXII the green schist dipped 28° towards the N. 4o° W. and farther down 57° S. At the point where the glen debouches upon the open expansion the red sandstone crops out on its left-hand side at 65° towards the S. 35° W. Far away in the west, the mountains, as seen from this same point, presented the same red shades, and are no doubt composed of the same rocks.
IIIFカラー高解像度
