Prairie du Chien Group (L. Ord.) in the Upper Mississippi Valley Open-file report; contains unpublished data that has not yet been peer-reviewed. Bedrock Geology Data and Resources WOFR1971-02 Prairie du Chien Group (L. Ord.) in the Upper Mississippi Valley Davis, R.A., Jr.; 1971 Report: 71 p. Download Related Collections Open-File Report View Open-File Report