National Geographic : 1900 Mar
ICE-CLIFFS ON WHITE RIVER, YUKON TERRITORY of the confluence of the White and Katrina, scores of them being vis ible from the summit of a small table-topped mountain immediately west of the mouth of the latter stream. There is no reliable map of the White and its tributaries in existence, since nearly all of them show Ladue Creek as about equal, if not superior, to the Katrina in size, whereas it discharges less than one-tenth as much water as the latter, which almost equals the main stream in size. The Nisling River of the maps I was unable to find unless it is represented by a comparatively small creek which does occur in the vicinity indicated: There is considerable evidence of recent volcanic activity in the valley of White River, and this evidence is much more pronounced in the region between the White and Yukon. It is in this section that we must look for the mountain or caldera responsible for the immense deposit of volcanic pumiceous ash which forms so notice able a feature of the banks of the Yukon from Caribou crossing to Dawson, a distance of 520 miles by the course of the stream. There is not a trace of it to be seen along the banks of the White except near the mouth, while it is very noticeable along the banks of some of the creeks between the latter and the Yukon. This would pre clude the possibility of this deposit being caused by an outburst from Mt Wrangell, as suggested by Dawson,* as an outburst from any mountain in the vicinity of Wrangell would undoubtedly deposit even a greater layer of the ash on the White than it would on the Yukon. Another theory regarding this deposit,t viz., that it is not of recent date and that deposition took place in water while the upper Yukon was yet a great inland lake and before the present river channel had been cut, is also untenable, as the ash in many places may be found overlying old drift-piles of perfectly sound wood, notably at the mouth of Stewart River and again above the mouth of the Pelly. It there fore still remains for some energetic member of the next Dominion Geological Survey party that traverses this region to locate the caldera from which such an extensive and remarkable deposit has been ejected. The solution of the question is certainly worthy of an effort. * Report on an exploration of the Yukon district, N. W. T., 1887, George M. Dawson, p. 45. B. Dawson Bros., 1888. tAlaska and the Klondike, Angelo Heilprin. D. Appleton & Co., 1899.