During, the summer of 1935 the writer studied the topographic forms and unconsolidated sediments of the Yukon Valley between Tanana and Holy Cross and found that the Yukon River is shifting over a broad lowland area. The magnitude and manifest rapidity of the process were so arresting that an attempt was made to discover the mechanism involved and the extent and rate of the activity. An analysis of the data collected affords approximate solutions of these problems and is presented in the following pages.
The most conspicuous evidence of channel shifting is the broad meander belt. The block diagram in the writer’s preceding article (Eardley, 1938, fig. 1) represents the nature of this physiographic feature with the limited accuracy that existing maps, observations from the river, and sketches and photographs from the air allow. At Tanana it is 6 to 10 miles wide; it narrows . . .