TO DAVID DALE OWEN, M.D., 
PRINCIPAL GEOLOGIST FOR THE EXPLORATION 
OF IOWA, WISCONSIN, AND MINNESOTA. 
Sir: I send you, herewith, a Report of the observations made by me, in accordance 
with instructions received from you, at different times, during the progress of the 
Geological Survey, under your direction, in the years 1847, 48, 49, and ’50. 
Allow me, at the same time, to bear testimony to the ability and energy with 
which you conducted the work, and to express my acknowledgments for the many 
kindnesses received at your hands during my connexion with the Survey. 
Yours, truly, 
J. G. NORWOOD. 
