National Geographic : 1900 Mar
ICE-CLIFFS ON WHITE RIVER, YUKON TERRITORY 115 mounted by. about six feet of earth, with the usual superimposed layer of decomposed vegetable matter. On seeing the first two I at once recalled to mind an article by Lieut. J. C. Cantwell on " Ice-cliffs on the Kowak River."* The diminutive magnitude, almost pigmy in size, of these cliffs as compared with those seen on the Kowak by Lieut. Cantwell, may to a great extent be accounted for by the differ ence in latitude and amount of winter precipitation. Lieut. Cant well does not state the depth of the winter's snow, but says " the banks of the stream in the region where the ice-cliffs are found are not all filled with ice," which is sufficiently suggestive. The greatest depth of snow in midwinter on the White River (except about the ex treme headwaters near the Coast Range) is only about four and one-half feet, and it is dry and powdery, disappearing rapidly in spring with out causing nearly as much of a freshet as I had anticipated. No loose ice whatever remains along the banks of the river through the summer, though it is to be found in the V-shaped gulches and valleys of the smaller affluents. It was only on seeing the third cliff that the true nature of these ice-masses suggested itself to me, viz., that they are the remnants of buried glaciers through which the stream has recently cut its way. There is ample evidence of recent and vigorous erosion, the water at present being so surcharged with a mixture of fine blue clay and granitic sand that a bucket of it on being allowed to settle will reveal a deposit of about one-fourth inch in depth, while small boulders and pebbles are being forced along over the bars and riffles by all the vigor of a seven to ten-mile current. On the other hand, the evidence of glacial action, at least of recent date, is lacking, so far as my observa tion went, though a more thorough examination, particularly among the harder rocks of the divides and crest lines, will, I think, reveal former activity. Such glacial action as did occur will probably prove to be due to local glaciers, as there is no evidence of either a large con tinental ice-sheet or of the amount of precipitation necessary for its formation. The third cliff occupied the bottom of a small valley, and its ap pearance, together with the stunted growth of black spruce on its sur face, so strongly resembled the tracts I had seen on the headwaters of the Klotassin in March, and then supposed were old lake beds, that I was at once forced to the conviction that the cause was the same in *NATIONAL GEOGRAPHIC MAGAZINE, vol. VII, p. 345, Oct., 1896.