An early geological survey of the area between Prairie du Chien (here Fort Crawford and Kipy Saging) and north along the Mississippi River to the Minneapolis area and further north beyond Duluth. Extends east to include the rapids along the northern reaches of the Wisconsin River. A legend in the lower right explains the use of color to indicate the twelve different geological formations. This scarce map was prepared to illustrate David D. Owen's report on his geological reconnaissance. Owen and his staff are reported to have worked 12-15 hours every day during the summer and winter of 1847 for this notable survey.

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Condition: B

Issued folding, now pressed and backed with archival tissue. Original hand coloring. Some light fold toning.