312 GYANTSÉ TO LHASA [chap.
had become deposited, which on the falling of the floods had been blown by the wind over the surrounding country for several miles, deluging the fields with its tawny billows, and converting them into a desert. These destructive sand-waves are still advancing, and along the foot of the rocks they form high rolling dunes of shifting hillocks over 20 feet high, and have sent off yellow arms fingering away up the mountain sides for a mile or more.
The old iron chain suspension - bridge spans picturesquely the main stream of the river about 200 yards below the ferry, under the monastery which bears its name, "The holy hill of the Iron Bridge" (Chak-sam ch'ö-ri). It is of the kind met with in Western China, and, according to the local tradition, was built in the early part of the fifteenth century A.D. by the sage T'angtong-the-King,1 now a canonised saint, whose image is worshipped not merely in the adjoining monastery, which he is also said to have built, but in the chief temples throughout the country as well. This pontifex is figured of a dark complexion, with long white hair and beard, and seated holding a thunderbolt in his left hand and an iron chain in his right. He is credited with having built eight such bridges over the Tsangpo. His monumental handiwork here of itself certainly entitles him to the respect of the inhabitants; for although it is not used at present, owing apparently to the river having burst for nearly half its waters a fresh channel to the north, and so having left the northern end of the bridge stranded amidstream, the structure itself still stands firmly after all these centuries, a magnificent piece of engineering work in the wilds of Tibet. It is about 150 yards in length and 15 feet above flood-level, and stretches between two tall masonry piers which are characteristically given the shape of the sacred chorten. The northern
1 Born in 1385 a.d.
