REPORT 



OF A 



GEOLOGICAL SURVEY 



OK 



WISCONSIN, IOWA, AND MINNESOTA; 



AND INCIDENTALLY OF 



A PORTION OF NEBRASKA TERRITORY. 



MADE UNDER INSTRUCTIONS FROM THE UNITED STATES TREASURY DEPARTMENT. 



BY 



DAVID DALE OWEN, 



UNITED STATES GEOLOGIST. 



PHILADELPHIA: 



LIPPINCOTT, GRAM BO & CO. 



1 8 5 2, 



