AMERICAN GEOLOGY MACLUREAN ERA, 1785-1819. 



241 



Mississippi Valley and the copper regions of Lake Superior both prof- 

 iting by his labors. 



Being brought in contact with the aborigines and realizing the 

 rapidity with which they were becoming contaminated through con- 



tact with the whites, he was drawn into a study of the Indian tribes 

 of North America, to which work, after 1822, he gave up a large por- 

 tion of his time, The main work of his life lies, therefore, quite 

 outside the limits of the present paper. 



NAT MUS 1904 16 



