530 APPENDIX. 



On the western side of Keweena Point, the same ore appears 

 under different circumstances, being disseminated through the 

 body of the trap-rock, in grains varying in size from a pin's head 

 to a pea. Although many of these grains are wholly copper black, 

 they are occasionally only depositions of the mineral upon specks 

 of carnelian, chalcedony, or agate, or are more frequently com- 

 posed, in part, of what is apparently an imperfect steatite. The 

 ore is so connected with, and so much resembles in color the 

 rock, of which it may be said to be a constituent part, that they 

 might easily, during a hasty examination, be confounded. A 

 random specimen of the rock furnished, upon analysis, 3.2 per 

 cent, of pure copper. The rock continues combined with that 

 mineral for nearly the space of three miles. Extremely thin veins 

 of copper black were observed to traverse this same rock ; and 

 in enlargements of these were discovered several masses of amor- 

 phous native copper. The latter mineral appeared in two forms 

 — the one consisting of compact and malleable masses, varying 

 from four to ten ounces each ; and the other, of specks and fasciculi 

 of pure copper, binding together confused masses of copper green, 

 and partially disintegrated trap-rock ; the latter was of several 

 pounds' weight. Each variety was closely embraced by the rock, 

 although the action of the water upon the rock had occasionally 

 exposed to view points of the metal. In addition to the accom- 

 panying copper green, which was in a disintegrated state, small 

 specks of the oxide of copper were associated in most of the native 

 specimens. 



Circumstances would not permit an examination of any portion 

 of the trap formation, except that bordering directly upon the lake. 

 But facts would lead us to infer that that formation extends from 

 one side of Keweena Point to the other, and that a range of thickly 

 wooded hills, which traverses the point, is based upon, if not formed 

 of that rock. An Indian information, which, particularly upon such 

 a subject, must be adopted with caution, would sanction the opinion 

 that the prominent constituents are the same wherever the rock is 

 observed. 



After having duly considered the facts which are presented, I 

 would not hesitate to offer, as an opinion, that the trap-rock forma- 

 tion was the original source of the masses of copper which have 

 been observed in the country bordering on Lake Superior ; and 



