Page:The cruise of the Corwin.djvu/48

 glacial denudation which these ancient lavas have undergone is very great; so great that now every feature presented, with the exception of the few recent craters, is glacial.

The glaciers, that a short tune ago covered all the islands, have sculptured the comparatively featureless rock masses into separate mountain peaks, and perhaps into separate islands. Certainly they have done this in some cases. All the inlets or fiords, also, that I have seen are simply the channels of the larger of those old ice rivers that flowed into the sea and eroded their beds beneath its level. The size and the trend of every one of these fiords correspond invariably with the size and the trend of the glacier basin at its head, while not a single fiord or canon may be found that does not conduct back to mountain fountains whence the eroding glacier drew its sources. The Alaska Peninsula, before the coming on of the glacial period, may have comprehended the whole of the Aleutian chain, its present condition being mostly due to the down-grinding action of ice. Frost and fire have worked hand in hand to produce the grand effects presented in this majestic crescent of islands.