REPORT. 



WASHINGTON, April 22, 1836. 



Lieut. Col. J. J. ABERT, 



U. S. Topographical Engineers : 



SIR : In obedience to your instructions, dated July 7, 1835, 

 directing me to proceed to the vicinity of that elevated ridge 

 which separates the Missouri river from the St. Peter's, the 

 chief northwestern tributary of the Mississippi, hitherto des- 

 ignated on the maps by the appellation of Coteau de Prairie, 

 and indicating Green Bay as a point on my route from whence 

 an opportunity would be afforded of examining the mineral 

 structure of the country on the Wisconsin river, I left this 

 city on the 8th of the same month, and have now the honor 

 to transmit a report of my proceedings. 



Before, however, I enter upon that part of my report imme- 

 diately connected \vith my instructions, I desire to explain 

 why I have been induced to extend this document, and lend 

 to it a character perhaps not generally expected of it. 



Well acquainted with the strong and general desire ex- 

 pressed for the acquirement of geological knowledge in this 

 country, and aware of the importance which would soon be 

 attached to it if proper measures were taken to awaken the 

 public attention, I thought it my duty, when drawing up my 

 report in 1835, concerning the elevated country between the 

 Missouri and Red rivers, to give a somewhat elementary ex- 



