GHOLBUGICAL BREPORT 
OF 
LOCAL, DETAILED OBSERVATIONS, 
IN THE VALLEYS OF THE 
MINNESOTA, MISSISSIPPI, AND WISCONSIN 
RIV ERS, 
IN THE YEARS 1848 AND 1849, 
DAVID DALE OWEN, 
UNITED STATES GEOLOGIST. 
Pion Fo ORT eA ee, 
HEAD OF SUBCORPS. 
