Burrard continues: »The water-parting between the Indian and Tibet basins cannot be drawn with certainty: in places it is without doubt the Kailas range, but the latter has been cut through from the north by feeders of the Brahmaputra whose basins have not been determined. The Lhasa river, the Charta and others drain the trough north of the Kailas range, and pierce the Kailas range in the same way as the Himalayan rivers pierce the Himalayan ranges.» This view is perfectly right, although we should remember that both orography and hydrography have proved to be more complicated than it was believed when Burrard wrote. One cannot speak of a long trough north of a continuous Kailas range parallel to the Tsangpo. But some rivers, amongst them the two mentioned by Burrard came from — either a water-parting range or a water-parting valley-threshold between two ranges and pierce other ranges situated further south and nearer to the Tsangpo. Therefore the comparison with the Himalaya is quite correct, although in the Transhimalaya it is not always the pierced ranges which are the highest. In the section where Wood measured his high peaks it is so, but not further east, where Nien-chen-tang-la is the water-parting.
Another proof of the near relationship between the Great Himalaya and Ladak range may be found in the description given by the native explorer who crossed the Photu pass in 1873. Of this important crossing Burrard says : I »The height of the Photu Pass he found to be 15 o8o feet above sea-level and 25o feet above the plains of the Brahmaputra to the north. This low depression in the Ladak range is a peculiar feature. It may have been carved by the Kali Gandak in a former geological age, when that river had its sources in Tibet and further north than at present.»
I crossed the same pass in the opposite direction, June 1907 and had an opportunity to see that the native explorers' description was perfectly correct. My Tibetan followers called it Kore-la. This may be the ordinary name amongst the Tibetans north of the pass, whereas Photu-la may be the name used on the southern side. For the present moment I will only quote what I have said about the place in my popular work: 2 »We have mounted only 315 feet from the river to the Kore-la, where the height is 15 292 feet. And from the pass there is a headlong descent to the Kali Gandak . . . The tentacles of the Kali Gandak are eating back northwards into the mountains much more quickly than the Tsangpo is eroding its valley. Some time or other, perhaps in a hundred thousand years, the Ganges system will have extended its tentacles to the bank of the Tsangpo, and then will be formed a bifurcation which, in the course of time, will bring about a total revolution in the proportions of the two rivers and their drainage areas.»
Whether the Kali Gandak, as Burrard thinks, has once had its sources further north in Tibet, or, as I presume, it will return to the north in future, or, which is
I Op. cit. p. 147. Compare also ibidem p. 155. — Vide Map, Vol. II, Pl. XXIV. 2 »Trans-Himalaya», London 1909, II, p. 78.
IIIFカラー高解像度
