Valley Floor Sedimentation in the Upper Mississippi Valley: Reply.

The primary purpose of my original paper was to examine historical rates of accelerated valley floor sedimentation in the Lead-Zinc District of the Upper Mississippi Valley. The principal conclusion that the temporal and spatial variations of historical floodplain sedimentation have been significantly influenced by "land use, climatic events, and changes in channel morphology. . ." remains unchanged. I am sorry that Trimble feels that some of his work was not properly acknowledged, but I feel this belief results from his apparent unawareness of my own and my students' published research that predates the initiation of his research in the region and from his apparent misunderstandings of regional variations in geologic and physiographic circumstances. Finally, I agree with his statement (p. 599) that: "It is therefore incumbent on us in our ongoing studies to insure that we obtain all the evidence, sift it thoroughly, report it carefully and give attribution for previous work." [ABSTRACT FROM AUTHOR]