by the Bagmatti river. This famous valley, surrounded by mountains, is 16 miles long and broad, and from 4200 feet to 4700 feet above the sea.
Sikkim, called Demo-jong in Mr. Bogle's narrative, is drained by the river Tista, and its affluents, the Lachen and Lachung, the Buri Bangit, the Moing, the Kangri, and Rangchu ; and the Am-machu rises near Pari-jong, at the foot of the Ohumalhari Peak (23,929 feet), and flows through the Chumbi valley, which separates Sikkim from Bhutan. It con- tinues its course through the plains of Julpigori as the Tursa. Two passes, the Kongra-lama and Donkia, besides others at the heads of the Lachen and Lachung tributaries of the Tista, lead from Sikkim to Tibet; while Pari-jong, at the head of the Chumbi valley, is the pass used by Bogle, Turner, and Manning. The Chumbi valley belongs to Tibet, and not to Sikkim; though the Sikkim Eajah has a house at Chumbi, and resides there during part of the year. The lofty spur dividing the Chumbi and Tista valleys, called the Chumbi Eange, is traversed by several passes, the Yak-la, Cho-la, and Jelep-la. From the eastern boundary of Chumbi, the states of Bhutan and Tawang extend nearly to the Lopra-cachu, a distance of about 200 miles, with an average width of 90 miles from the alpine passes of the Southern Himalaya to the plains of India.
The duars of Bhutan — literally doors or approaches — em- brace the strip of land extending along the foot of the Bhutan mountains in Bengal and Assam, like the terai or murung of Sikkim and Nepal. There are eighteen of these diiars or passes: eleven on the frontier of Bengal, and seven on that of Assam ; the breadth of this diiar tract being from ten to twenty miles, and the length 220 miles. The more southern frontiers are aU partially under rice cultivation, but the inter- vening space to the foot of the mountains is occupied by dense and lofty forest, and heavy grass jungle. Several streams and nvers flow over pebbly beds from the gorges of the different defiles to the Brahmaputra. The most northern portion of the
