The observations here recorded were made in the course of geologic investigations dealing primarily with the mineral resources of Alaska and were, therefore, incidental rather than the main objects of research. For this reason, as well as from the fact that the phenomena are highly complex, the present paper aims at little more than the presentation of some of the scattered observations that indicate the types of features recognized, leaving the coordination and the detailed working out of the Pleistocene-Recent history to the future.
In the Koyukuk-Kobuk region shown in figure 1 the eenter of ice occupation in the past was the highlands to the north of the Kobuk, but the Zane Hills near the Koyukuk show evidences of past glaciation in the form of the valleys and in small moraines similar to that of figure 1, plate 34, which has a steep ice contact slope on . . .