200 THE PEAKS AND MOUNTAIN RANGES
view of the weathering character and apparent structure of the peaks themselves. From such observations it has been found that almost all the peaks of 25,000 feet or more in height are composed of granite, gneiss, and associated crystalline rocks, It had long be supposed that some of the granites found on the flanks of the great peaks which presented a foliated appearance were of sedimentary origin, and had therefore been once deposited beneath the sea. But their truly intrusive nature was recognised by the late Lieutenant-General M‘Mahon, who proved conclusively that the great central gneissose rock of the Himalayas was in reality a granite crushed and foliated by pressure. It may certainly be taken that both K* and Nanga Parbat are composed of granite, and have been intruded or compressed upward from beneath the earth’s crust.
Mr. Hayden further concludes that the ex- ceptional height of these great peaks is due to their being composed of granite, for either the superior power of the granite to resist the atmospheric forces tending to their degradation has caused them to stand as isolated masses above surrounding areas of more easily eroded rocks, or they are areas of special elevation.
