350) Account of the Native Copper 
to the observations of Captain Douglass. It is connected 
by portages with the Menomonie river of Green Bay, and with 
the Chippeway river of the Mississippi, routes of communication, 
occasionally travelled by the Indians in canoes. At its mouth 
there is a village of Chippeway Indians of sixteen families who 
subsist chiefly, on the fish (sturgeom) taken in the river; and 
whose location, independently of that circumstance, does not ap= 
pear to unite the ordinary advantages of Indian villages in that 
region. A strip of alluvial land of a sandy character extends 
from the lake up the river three or four leagues, where it is sue- 
ceeded by high broken hills of a sterile aspeet and covered chiefly 
by a growth of pine, hemlock, and spruce. Among these hills, 
which may be considered as lateral spurs of the Porcupine moun- 
tains, the Copper Mines, so called, are situated, 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 copper reposes on the west bank of the 
river, at the water’s edge (see Plate V. fig. 3), 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 con 
nexion with serpentine rock, the face of which it almost com- 
pletely overlays, and is also disseminated in masses and grains 
throughout the substance of the rock*, The surface of the 
* 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 amateurs of natural science, it may be 
proper to add—that the serpentine rock is not én situ, nor is it so found in 
any part of the regions visited. To aceount for its appearance in a section 
of country to which it is geologically foreign, it would be necessary to enter 
into the inquiry ‘‘ by what means have the loose masses of primitive rocks 
been transported into secondary countries ?”—an inquiry 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 sug- 
gest, what 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 ahundantly 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 he 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 
level of Lake Superior, their conical and rugged peaks, and other appears 
ances, are such as frequently characterize veleanic mountains. “1% 
metal, 
