Gravel deposits in which the combination of topography, composition, structure, and magnitude is unlike anything described in geologic literature are widely distributed over the channeled scablands of the Columbia Plateau in Washington and thence along the Snake and Columbia rivers as far down as Portland, Oregon. They record extraordinary conditions of origin. No hypothesis for channeled scabland which does not account for them can be worthy of consideration. The writer’s interpretation of channeled scabland2 is so great a departure from prevailing conceptions of rivers and river work that numerous suggestions have been made by other geologists looking toward more acceptable, more conventional explanations. In none of them, however, is there an adequate appreciation of the character of these gravel deposits, perhaps because no adequate descriptions have been made by the writer. The endeavor in this paper is to show clearly just what these deposits are and to show the . . .