Copper and Silver of Kewenaw Point, Lake Superior. 89 
or three have been selected, by my advice, as undoubtedly val- 
uable, and of sufficient magnitude and richness for profitable min- 
ing. ‘The others are problematical, and may perhaps ultimately 
be explored, by sinking shafts into them to some depth, whan the 
value of the ore may be estimated. 
The most valuable locality is on the west side of Eagle River,* 
eight miles from Eagle Harbor, and a mile and a half from the 
lake shore, on rocky land, elevated above the lakes about 200 feet. 
Fragments of the rock and lumps of native copper found at the 
mouth of the river, first attracted the attention of explorers to ex- 
amine the bed and banks of the stream, when metallic copper 
mixed with silver was discovered in place. This locality was 
then examined by me, and by the aid of the company of miners 
the value of the mine was sufficiently proved to warrant the out- 
lay required in exploring it thoroughly. An exploration shaft 
was then directed to be made, and the result has proved very 
satisfactory to the company. : 
The ore, if it may be so called, consists of an intimate mixture 
of copper and silver, and an alloy of those metals in an amygda- 
loidal trap rock, the cavities in it being filled with metallic glob- 
ules, and fine particles being thickly mixed with the rock, so as 
to constitute from 10 to 30 per cent. of its weight. 
The crevices and veins in the rock are also filled with thin 
sheets of an alloy of copper and silver, and occasional lumps of 
the metals are found of considerable magnitude. 
The most singular and interesting chemical and geological 
phenomenon observed at this place, is the occurrence of pieces of 
copper and silver, united together side by side by fusion, without 
any alloying of the silver, although the copper contains ;°, per 
cent. of silver, united with it chemically. The silver, however, 
is always absolutely pure. There are also specimens in which 
the copper alloy is absolutely porphyritic, with patches of fine 
silver. I have a piece, about the size of a dime, in which one 
half of it is pure silver, and the other an alloy of copper with 
#s per cent, of silver, containing patches of pure silver mixed 
with it but not alloyed, The two metals are completely soldered 
* Dr. Houghton says that this is not the stream known to voyageurs as Eagle 
River. I have therefore proposed to name it Silver River, a name evidently quite 
appropriate. 
Vol. xxix, No. 1.—April-June, 1845. 12 
