Definition.—A glacial lake, according to my use of the term in this paper and elsewhere, is a body of water bounded in part by a barrier of land-ice. The lake may be hemmed in by a glacier, as the Merjelen see, or by a continental ice-sheet, as Lake Agassiz. And the same name is also applicable to the lakelets, wholly bounded by ice, which are occasionally formed, attaining a considerable depth and extent and continuing through several years, on the surface of glaciers, as in the Himalayan range, or on an ice-sheet, as observed by Nordenskiöld in Greenland.
Extent and numbers.—The abundant and extensive development of glacial lakes here to be considered attended the recession of the ice-sheet of the second or last Glacial epoch in Canada, being due to the temporary damming of the waters of glacial melting and of rains on areas where the land . . .