Bulletin No. 26. The History of the Upper Mississippi River in Late Wisconsin and Postglacial Time

This study in glacial geology is the work of a botanist who is a firm believer in what has been aptly termed "cross-fertilization of the sciences." It developed gradually from a beginning that was purely botanical. An area of ancient dunes close to Minneapolis supports a flora that is distinctive and of unusual interest. An ecological investigation begun here necessitated consideration of the dunes themselves. Steadily the field broadened in the manner familiar to every scientific worker. The dunes led back to their source in the outwash. A great glacial lake disclosed itself. Finally the various elements resolved themselves into a history. in which the Mississippi River plays the leading role. Concurrently the botanical field expanded until it covered the vegetation of both dunes and outwash. with particular emphasis upon its development during post-glacial time. The foundational geologic study is here presented: the botanical part is still unwritten