412 APPENDIX. 



in huge boulders. Tlie most elevated rock, in place, on the 

 sources of the Mississippi, is found to be quartzite. This is at 

 the Falls of Pakagama. In coming down the Mississippi, soon 

 after passing the latitude of 46°, the river is found to have its 

 bed on greenstones and sienites, till reaching near to the Falls of 

 St. Anthony, where the great western horizontal limestone series 

 begins. To facilitate the study of the latter, opportunities were 

 sought of detecting its imbedded forms of organic life, but their 

 infrequency, and the rapid mode of our journeying, was averse 

 to much success in this line without the boundaries of the great 

 lake basins. 



lu the department of mineralogy, I have not as brilliant a col- 

 lection as I brought from Potosi in 1819 — but, nevertheless, one 

 of value — the country explored being a wilderness, and very little 

 labor having been applied in excavations. Among the objects 

 secuijed, I have fine specimens of the various forms of native 

 copper and its ores, together with crystallized sulphurets of lead, 

 zinc, and iron; native muriate of soda, graphite, sulphate of lime, 

 and strontian, and the attractive forms which the species of the 

 quartz family assume, in the shore debris of the lakes, under the 

 names of agate, carneiian, &c. The whole will be prepared and 

 elaborately reported to the Department. 



I found the freshwater shells of this region to be a very attract- 

 ive theme of observation in places 



"Where tlie tiger steals along, 

 And the dread Indian chants his dismal song;" 



where, indeed, there was scarcely anything else to attract atten- 

 tion; and I have collected a body of bivalves, which will be for- 

 warded to our mutual friend, Dr. Mitchell, for description. Indeed, 

 the present communication is designed, after you have perused 

 it, to pass under his eye. No one in our scientific ranks is more 

 alive to the progress of discovery in all its physical branches. 

 Governor Clinton, in one of his casual letters, has very happily 

 denominated him the Delphic oracle, for all who have a question 

 to ask come to him, and his scientific memory and research, in 

 books, old and new, are such, that it must be a hard question in- 

 deed which he cannot solve. 



!Next to him, as an expounder of knowledge, you, my dear sir, 



