100 



NARRATIVE OF THE EXPEDITION. 



being removed from the parent beds. The following sketches 

 depict the shapes of these masses. 



Fig. 2. 



Fig. 3. 



With respect to the general question of the mineral character 

 of this part of the country, and the probable value of its mineral 

 and metallic deposits to the public domain, the entire class of 

 facts, from which a judgment must be formed, are favorable.* 

 Salts and oxides of copper are not only seen in various places in 

 its stratification, but these indications of mineral wealth in this 

 article are confirmed, by the subsequent discovery of masses of 

 native copper, along the shore, and imbedded in its traps and 

 amygdaloids. In addition to the opportunities of observation 

 furnished by this expedition, subsequent public duties led me to 

 perform seven separate trips along its shores, and each of these 

 " but served to accumulate the evidences of its extraordinary 

 mineral wealth. Indications of the sulphurets, arseniates, and 

 other ores of this metal are found in the older class of horizontal 

 rocks ; but it is to the trap-rocks alone that we must look for 

 the veins of native metal. Some of these masses contain silver, 

 in a state of combination. Traces of this metal, chiefly in the 

 boulder form, are found in the metalliferous horizontal strata. 

 Nor is there wantino^ evidence, that there are localities of virmn 



* Vide Pieports in the Appendix: 1. Report on the Copper Mines of Lake Supe- 

 rior, November 6, 1820. 2. Report on the Value of the Existing Evidences of 

 Mineral Wealth in the Basin of Lake Superior to the Public Domain, October 1, 

 1822. 



