292 APPENDIX. 



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 for- 

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

 been observed in the country bordering on Lake Superior ; and 

 that at the present day, examinations for the ores of copper could 

 not be made in that country with hopes of success, except in the 

 trap-rock itself; which rock is not certainly known to exist upon 

 anyplace upon Lake Superior, other than Keweena Point. 



If this opinion be a correct one, the cause of failure of the 

 mining company in this region is rendered plain. Having con- 

 -Tf.dered each insulated mass of pure metal as a true indication of 

 the existence of a bed in the vicinity, operations were directed to 

 wrong points ; when, having failed to realize their anticipations, 

 the project was abandoned without further actual investigation. 

 We would be induced to infer, that no attempts were made to 

 learn the original source of the metal which was discovered, and 

 thus, while the attention was drawn to insulated masses, the ores, 

 ordinary in appearance, but more important in situ, were neglected ; 

 and perhaps from the close analogy in appearance to the rock 

 with which they were associated, no distinction was observed. 



What quantity of ore the trap-rock of Keweena Point may be 

 capable of producing, can only be determined by minute and 

 laborious examination. The indications which were presented by 

 a hasty investigation are here imbodied, and, with deference, 

 submitted to your consideration. 



I have the honor to be, 



Sir, your obedient servant, 



Douglass Houghton. 



