east of which the Sumdang-tsangpo flows out into the lake. A little above its mouth the river forms some lagoons and swamps without vegetation. The Lavar-tsangpo enters the western end of the lake, behind a headland visible to the N. 67° W. Before entering the lake the river is said to join the Rataung-chu, N.W. of Selipuk'; some Tibetans asserted the joint river was called Mamo-dunker-chu. To the N. 2I° W. and N. 17° W. are two small flat islands, and east of them a greater island or perhaps peninsula; due north and N. 3° E. are also islands or peninsulas, all along the northern shore; still further east, in the easternmost part of the lake, is the greatest island, parallel to the southern shore. To the N. 39° E. is the last and northernmost peak on the Surla range. Camp 438, at the little spring of Pebuk, is at 4 984 m. Here the rock is limestone.
There is a good deal of sand in the mouth of the little valley going down from Pebuk, and here again we come into contact with the very sharp drawn beach-lines which are seen stretching along the foot of the hills to both sides. The lines turn beautifully round a couple of isolated hills to the north of the route and form concentric rings around the little lake at their foot. These beach-lines are in immediate connection with those mentioned from the foot of the hills south of Camp 441. Camp 439 is at the bank of Sumdang-tsangpo a few metres above the sur-
face of Nganglaring-tso.
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