THE NATURE AND ACTIVITY OF CANADIAN GLACIERS.
By William Hittell Sherzer.
None the less attractive the glacial student than to the mountain climber is that grand array of peaks and snow-fields which stretches poleward through the western part of the Dominion of Canada. Here upon a magnificent scale and in endless variety and profusion one may recognize the various types of glaciers, detect in them every feature known to science and about them every form of geological activity ascribed to these great engines of rock destruction and transportation. About the peaks and ridges and in the higher valleys there accumulates season after season layer upon layer of snow, which, by its own pressure, surface melting and occasional rain or cloud mist is gradually compacted into ice. Indefinite accumulation of this congealed moisture is prevented by one of those beneficent provisions of Nature by which, under the influence of its own weight, this ice in frozen streams, or shorter tongues, moves slowly to lower levels where complete melting may occur and this moisture again be put into general circulation. Were it not for this the Canadian Rockies and Selkirks would be encased in a great ice ridge, extending as high into the atmosphere as it is possible for moisture to be lifted, from the sides of which tremendous avalanches would hurl themselves to the adjacent plains, deeply covering regions now free from snow during a portion of the year.
Although the mechanics of glacial motion are not yet fully understood, these ice-streams appear to move much as would a similar mass of asphaltum, with which
