68 Mr. J. Taylor on Mr. Schoolcraft's " Account of the [Jan. 



rivers of the Mississippi, contains very frequent, and some 

 most extraordinary imbedded masses oi" native copper; but 

 that no body of it, which is sufficiently extensive to become 

 tlie object of profitable mining operations, is to be found at 

 any particular place. This conclusion is supported by the facts 

 already adduced, and so far as theoretical aids can be relied 

 upon, by an application of those facts to the theories of 

 mining. A further extent of country might have been embraced 

 alon^ the shore of lake Superior, but the same remark appears 

 applicable to it. 



** 2d. That a mineralogical survey of the rock formations 

 skirting the Ontonagon, including the district of country above 

 alluded to, would result in the discovery of very valuable 

 mines of the sulphuret, the carbonate, and other profitable 

 ores of copper ; in the working of which the ordinary advan- 

 tages of mining would be greatly enhanced by occasional 

 masses, and veins of native metal. This deduction is rendered 

 probable by the general appearance of the country, and the 

 concurrent discoveries of travellers, — by the green coloured 

 ^waters which issue in several places from the earth, — by the 

 bodies of native copper found, — by the cupreous tinge which 

 is presented in the crevices of rocks and loose stones, — by the 

 geological character of the country, and by other analogous 

 considerations." 



The statement which is made by Mr. Schoolcraft that has 

 particularly induced me to notice his paper is contained in the 

 following paragraph : 



** The discovery of masses of native copper is generally con- 

 sidered indicative of the existence of mines in the neighbour- 

 hood. The practised miner looks upon them as signs which 

 point to larger bodies of the same metal in the earth, and is 

 often determined, by discoveries of this nature, in the choice 

 of the spot for commencing his labours. The predictions 

 drawn from such evidence, are also more sanguine in propor- 

 tion to the extent of the discovery. It is not, however, an 

 unerring indication, and appears liable to many exceptions. 

 A detached mass of copper is sometimes found at a great dis- 

 tance from any body of the metal, or its ores ; and these, on 

 the contrary, often occur in the earth, or imbedded in rock 

 strata, where there has been no external discovery of metallic 

 copper to indicate it." 



The opinion here expressed, and which is given as that of 

 practised miners, is certainly incorrect ; it is one indeed which 

 nas been often repeated by the writers of books, but which I 

 will venture to add does not rest on the testimony of practical 

 men. Detached, or insulated masses of native copper, or even 

 of the richer kinds of ore, do not of themselves indicate the 

 proximity of valuable mines, and in fact their occurrence is rare 

 even in the most productive districts. 



