INTRODUCTION. 



I trust 1 may be permitted, by way of introdQction, to premise a few 

 words as regards the origin of the map which this report is intended to 

 illustrate, as well as of my connexion with the later expedition that served 

 to complete it. 



Having come to this country for the purpose of making a scientific tour, 

 and with the view of contributing to the progressive increase of knowledge 

 in the physical geography of North America, I determined, after having ex- 

 plored the Alleghany range in its various extensions through the southern 

 States, and having ascended the Red river, Arkansas river, and to a great 

 distance the Missouri river, to undertake the full exploration of the Missis- 

 sippi river from its mouth to its very sources. During the five years that 

 I was engaged in these excursions, I took occasion to make numerous ob- 

 servations, calculated to lay the foundation of the astronomical and physical 

 geography of a large extent of country, and more especially of the great 

 and interesting region between the falls of St. Anthony and the sources of 

 the Mississippi. With these labors I connected, also, the study of the cus- 

 toms, habits, manners, and languages of the several Indian nations that oc- 

 cupy this vast region of country. 



At the expiration of this long (and. as 1 found it, arduous) journey, 1 re- 

 turned to Baltimore, among my good friends of St. Mary's College, where 

 I soon received a flattering invitation from the War Department and Topo- 

 graphical Bureau to repair to Washington. Theresultsof my travels were 

 made known to these departments ; upon which they thought proper to 

 intrust me with the command of an expedition, to enable me to completBj 

 to the greatest advantage, a scheme which I had already projected on my 

 first visit to the Far West — namely, the construction of a geographical and 

 topographical map of the country explored. 



To be more explicit, I subjoin a copy of the instructions transmitted to 

 me : 



Bureau of Topographical Engineers, 



WasMnglon, April 7, 1838. 

 Sir: I am aulhorized by the honorable Secretary of War to inform you that you will be ea»- 



Sloycd lo collect additional materials for the map now in hand, of those parts of the United 

 Itates, and their territories, which lie west of the Mississippi. 



