COMPOSITION OF PEAKS 201
Now it is found that the axes of the great mountain ranges are also composed of granite, and it seems probable that special elevating forces have been at work to raise certain parts of their ranges above the general level of the whole. And when once such elevation has been brought about, the disparity between the higher peaks and the inter- vening less elevated area would undoubtedly be intensified by the destructive forces at work, for the mantle of snow and ice, while slowly carrying on its work of abrasion, would serve as a protection for the peaks against the disintegrating forces of the atmosphere, while the lower unprotected areas would be more rapidly eroded.
So argues Mr. Hayden, who further demon- strates that when, during the development of the Himalaya as a mighty mountain range vast masses of granite welled up from below, forcing their way through and lifting up the pre-existing rocks superimposed upon them, it is probable that, owing to dissimilarity of composition and to structural weaknesses in certain portions of the earth’s crust, movement was more intense at some points than at others, and that the granite was raised into more or less dome-like masses standing above the general level of the growing -range, and
