204 Mr. Schoolcraft on the 



A strip of alluvial land of a sandy character extends from 

 the lake up the river three or four leagues, where it is suc- 

 ceeded by high broken hills of a sterile aspect and covered 

 chiefly by a growth of pine, hemlock, and spruce. Among 

 these hills, which may be considered as lateral spurs of the 

 Porcupine mountains, the Copper Mines, so called, are situ- 

 ated, at the distance of thirty two miles from the lake, and 

 in the centre of a region characterized by its wild, rugged, 

 and forbidding appearance. The large mass of native cop- 

 per reposes on the west bank of the river, at the water's 

 edge, and at the foot of a very elevated bank of alluvion, 

 the face of which appears, at some former period to have 

 slipped into the river carrying with it the mass of copper 

 together with detached blocks of granite, hornblende, and 

 other bodies peculiar to the soil of that place. The copper, 

 which is in a pure and malleable state, lies in connexion with 

 serpentine rock, the face of which, it almost completely 

 overlays, and is also disseminated in masses and grains 

 throughout the substance of the rock.(l) The surface of 

 the metal, unlike most oxydable metals which have suffered 

 a long exposure to the atmosphere, presents a metallic bril- 

 liancy ;* which is attributable either to alloy of the pre- 



(1) In preparing this report, a more particular description of the geog- 

 nostic character of this mass of copper was deemed unnecessary, but in 

 presenting it for the perusal of the amatuers of natural science, it may be 

 proper to add — that the serpentine rock is not in situ, nor is it so found in 

 any part of the regions visited. To account for its appearance in a section 

 of country to which it is geologically foreign, it would be necessary to enter 

 into the enquiry "by what means have the loose masses of primitive rocks 

 been transported into secondary countries" — an enquiry which is incom- 

 patible with the limits of this report, and which, moreover would, in itself, 

 furnish the subject of a very interesting memoir. I will now however 

 suggest, v/hat has struck me in passing through that country — that the Por- 

 cupine mountains which are situated thirty miles west, are the seat of ex- 

 tinguished volcanoes that have thrown forth the masses of native copper 

 which are found (as will be mentioned in the sequel) so abundantly through- 

 out the region of the Ontonagon. This opinion is supported by the fact 

 that those mountains are composed (so far as observed) of granite, which is 

 probably associated with other primary rocks, and among them serpentine — 

 that the red sand-stone rock at their base is highly inclined towards the 

 mountains so as to be almost vertical, and apparently thrown into this posi- 

 tion by the up-heaving of the granite — and also, that their elevation which 

 has been calculated by Capt. Douglass and myself at 1800 feet above the 

 IriveJ of lake Superior — their conical and rugged peaks, and other appear- 

 ances, are such as frequently characterize volcanic mountains. 



* This however, is no uncommon appearance of native copper. — Ed. 



