212 Mr. Schoolcraft on the 



earth, or imbedded in rock strata, |vhere there has been no 

 external discovery of metalHc copper to indicate it. So far 

 as the opinions of mineralogical vvriters can be collected on 

 this point, they teach,— that large] veins of native copper 

 are seldom found, but that it is frequently disseminated in 

 masses of various size in the rocks, and among the spars 

 and ores of copper and other mii^es ; and when found in 

 scattered masses upon the surface, is rather to be consider- 

 ed as a token of the existence of the sulphuret — the car- 

 bonate, and other ores of copper, within the circle of coun- 

 try where it occurs, than as the precursor to contiguous 

 bodies of the same metal. " Native copper" says Cleve- 

 land, " is found chiefly in primitive rocks, thrpy^ J^^^^i^ J^ 

 is sometimes disseminated, or m|^ fr^qflentiy it drit^rsj'nto 

 the composition of metallic vein^jW^ich traverse tli,ese,^rpcks. 

 It is thus connected with grajapwhe, gheiss, micaceou^^^nd ar- 

 gillaceous slates, granular jimestonje, chlorite, serpentine, 

 porphyry, &c. It also occurs, in 'Iransition and secon- 

 dary rooks. It accompanies other ,9rfes of copper, as the 

 red oxyde, the carbonate and sulphuret of copper, pyritous 

 and grey copper, also the red and brown oxides of iron, 

 oxide of tin, Sic. Its usual gangues are quartz, the fluate 

 and carbonate of hme, and sulphate of barytes. At Ober- 

 stein it occurs in prehnite; and in the Faroe islands, it ac- 

 companies zeolite. 



" Native copper is not rare, nor is it found in sufficient 

 quantity to be explored by itself. It sometimes occurs in 

 loose, insolated masses of considerable size." (1) 



From all the facts which I have been able to collect on 

 lake Superior, and after a deliberation upon them since my 

 return, I have drawn the following conclusions : — 



1st. That the alluvial soil along the banks of the Onton- 

 agon river, extending to its source, and embracing the con- 

 tiguous region which gives origin to the Menomonie river of 

 Green Bay, and to the Ousconsing, Chippeway and St. 

 Croix rivers of the Mississippi, contains very frequent, and 

 some most extraordinary imbedded masses of native copper ; 

 but that no body of it, which is sufficiently extensive to be- 

 come the object of profitable mining operations, is to be 

 found at any particular place. This conclusion is support- 



(1) Ckyeland's Mineralogy, p. 450. 



