Central Chain lead the drainage, for a distance of 150 miles, into the Aran river, which breaks through the Southern Himalaya into Nepal. North of the Arun basin, and, like the Palti lake, encircled by spurs from the Central Eange, is the Chomto-dong lake, about 20 miles in length and 16 broad, and without an outlet. It is not shown on the map of D'Anville, and was, therefore, discovered by No. 9 in 1871. This lake is 14,700 feet above the sea. The main chain of the Central Eange towers over the Chomto-dong lake on its northern side, and is crossed by the Lagalung-la pass 16,000 feet above the sea, where the glacier ice is seen close to the road taken by travellers. According to No. 9 this part of the region between the Central and Southern Kanges belongs to Sikkim, and the boundary between Sikkim and Tibet is on the Lagulung-la of the Central Kange. The Central Eange has also been crossed (by No. 9) by the Dango-la pass above the great Sakia monastery, and 28 miles east of the Lagalung-la. The western branch of the Aran flows from west to east through an extensive plain, be- tween the Central and Southern Eanges, called the Dingri[1] Maidan, 13,900 feet above the sea, where there is a town of two hundred and fifty houses. The Dingri river is believed to rise' in a large lake, which is shown but not named on D'Anville's map, but which was heard of as the Dalgu-chu, 15,000 feet above the sea, by Colonel Montgomerie's explorers. It has never been visited. Still farther to the west the Central Chain is crossed by the Taku-la pass,[2] which has never been explored; the No-la pass, at a height 16,623 feet above the sea; and the Photu-la, at a height of 15,080 feet. The latter is just above the town of Loh-Mantang,[3] a place of very considerable trade, and thousands of wild ponies find pasture on the slopes along the pass.
In Eastern Nepal, farther west, the only pass with which
