No one seems to have considered the possibility of using river gravel to determine the geomorphic history of a region. Students of this science have been taught to depend entirely on earth forms produced by erosion and to a certain, though small, extent on the gradient and alignment of streams in interpreting geomorphic history; as a result, they have relied implicitly on such features to furnish answers to all of their questions. It is now time to turn our attention to other possible lines of evidence, and, in the writer's opinion, the rock materials transported and deposited by streams during a partial or complete cycle of development is the most promising line of evidence that is available and is the one that will be considered in this paper.
The materials to which the writer refers are those rounded fragments of hard rocks which are . . .