THE HIMALAYAN NORTHERN WALL. 37

■southern buttresses of the lofty Tibetan plateau. The Himalayasproject east and west beyond the Indian frontier. Their totallength is about 1750 miles, and their breadth from north tosouth from 150 to 250 miles. 1

Regarded merely as a natural frontier separating India Thefrom the Tibetan plateau, the Himalayas may be described as j^,£j e ayana double mountain wall running nearly east and west, with a Wall andtrough or series of deep valleys beyond. The southernmostof the two walls rises steeply from the plains of India to20,000 feet, or nearly 4 miles in height. It culminates in.Kanchanjanga , 28,176 feet, and Mount Everest , 29,002feet, the latter being the loftiest measured peak in the world.

This outer or southern wall of the Himalayas subsides on thenorthward into a series of depressions or upland dips, re-ported to be 13,000 feet above the level of the sea, beyondwhich rises the second or inner range of Himalayan peaks.

The double Himalayan wall thus formed, then descendsinto a great trough or line of valleys, in which the Sutlej ,the Indus , and the mighty Tsan-pu (Sangpu) gather theirwaters.

The Sutlej and the Indus flow westwards, and pierce throughthe Western Himalayas by separate passes into the Punjab .

The Tsan-pu, after a long unexplored course eastwards alongthe valley of the same name in Tibet , finds its way throughthe Dihang gorge of the Eastern Himalayas into Assam , whereit takes its final name of the Brahmaputra . On the north ofthe river trough, beyond the double Himalayan wall, rise theKarakoram and the Gangri Mountains, which form thesouthern escarpment of the Tibetan table-land. Behind theGangris, on the north, the lake-studded plateau of Tibet spreads itself out at a height averaging 15,000 feet. Broadly.speaking, the double Himalayan wall rests upon the low-lyingplains of India , and descends northward into a river trough,beyond which, still farther to the north, rises the Tibetan plateau.

Vast glaciers, one of which is known to be 60 miles in length,slowly move their masses of ice downwards to the valleys.

1 he higher ranges between India and Tibet are crowned witheternal snow. They rise in a region of unbroken silence, likegigantic frosted fortresses one above the other, till their whitetowers are lost in the sky.

1 Some geographers hold that the Himalayan system stretches in acontinuous chain westwards along the Oxus to 68° E. long.; and that onlyan arbitrary line can be drawn between the Himalayan ranges and theelevated regions of Tibet to the north of them.