At the meeting of this Society in December, 1911, the senior author presented a paper under the same title as that above.2 In that paper it was set forth as having been determined in the preceding summer that the high flat-topped ridges of Cretaceous rocks east of the Rocky Mountain front in the region of Glacier Park, Montana, are capped with deposits of glacial drift which, because of its topographic relations and surficial modification by weathering, was regarded as much older than the drift in the intervening valleys. The valley drift was deposited by the mountain glaciers at the time of their last extension, which is regarded as having been practically coincident with the Wisconsin stage of continental glaciation. At that time, in 1911, the extension of the high-level drift eastward from the mountain front and its relations to the quartzite gravels, described by Calhoun, Dawson, and McConnell, as . . .