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. 



