80-i APPENDIX. 



Albany, March, 1822. 



Sir: Agreeably to your appointment as a member of the ex- 

 pedition to explore tlie sources of the Mississippi, by the way of 

 the Lakes, I proceeded to join the party organized for that pur- 

 pose at Detroit, by His Excellency Lewis Cass. Diurnal notes 

 were kept of the changes in the geological features of the regions 

 visited ; of the mineralogy of the country ; and of such facts as 

 could be ascertained, with the means at command, to determine 

 its general physical character and value* 



I have heretofore reported to you the facts and appearances 

 which indicate the existence of the ores of copper, and of valuable 

 deposits of copper in its native form, in the basin of liake Supe- 

 rior — a point which constituted one of the primary objects to 

 which my attention was called — and I now proceed to state such 

 particulars in the topics confided to me as fell within my ob- 

 servation. 



In generalizing the facts, it must be observed that the expedi- 

 tion had objects of a practical character relative to the number, 

 disposition, and feelings to be learned respecting the Indian tribes ; 

 that the transit over large portions of the country was necessarily 

 rapid; and that few opportunities of elaborate or long-continued 

 observations occurred at any one point. The topography was 

 committed to a gentleman who is every way qualified for that 

 topic, who was well supplied with instruments, and who will do 

 ample justice to that department, I make these remarks to pre- 

 pare you for a class of observations which are necessarily tech- 

 nical, and quite imperfect, and to which it is felt that it will not 

 be an easy task to impart a high degree of interest, whatever may 

 have been the anticipations. 



To prepare the mind to appreciate the account which I give of 

 changes and developments in the physical structure of the country, 

 it may be observed that the American continent has experienced 

 some of the most striking mutations in its structure at and north 

 of the great chain of lakes. That chain is itself rather the evi- 

 dence of disruptions and upheavals of formations, which give its 

 northern coasts, to some extent, the character of ancient — very 



* The two geological profiles of the Mississippi Valley and the Lake Basins ac- 

 companying the original are here omitted ; as, also, most of the illustrative views 

 of scenery which accompanied the original. 



