on the Southern Shore of Lake Supérior, €s’c. Sol 
metal, unlike most oxidable metals which have suffered a long 
exposure to the atmosphere, presents a metallic brilliancy*; which 
is attributable either to alloy of the precious metals, or to the 
action of the river, which during its semi-annual floods carries 
down large quantities of sand and other alluvial matter that may 
serve to abrade its surface, and kept it bright. The shape of the 
rock is very irregular—its greatest length is three feet eight 
inches—its greatest breadth three feet four inches, and it may 
altogether contain eleven cubic feet. In size, it considerably 
exceeds the great mass of native iron found some years ago upon 
the banks of Red River in Louisiana, and now deposited among 
the collections of the New-York Historical Society, but, on ac+ 
count of the admixture of rocky matter, is inferior in weight. 
Henry, who visited it in 1766, estimated its weight at five tonst. 
But after examining it with scrupulous attention, I have com- 
puted the weight of metallic copper in the rock at twenty-two 
hundred pounds. The quantity may, however, have been much 
diminished since its first discovery, and the marks of chisels and 
axes upon it, with the broken tools lying around, prove that por- 
tions have been cut off and carried away. The author just 
quoted observes, * that such was its pure and malleable state, 
that with an axe he was able to cut off a portion weighing a 
hundred pounds.” Notwithstanding this reduction, it may still 
be considered one of the largest and most remarkable bodies of 
native copper upon the globe, and is, so far as my reading ex- 
tends, exceeded only by a specimen found in a valley in Brasil 
weighing 2666 Portuguese pounds §. Viewed only as a subject 
for scientific speculation, it presents the most interesting consi- 
derations, and must be regarded by the geologist a saffording il- 
lustrative proofs of an important character. Its connexion with 
a rock which is foreign to the immediate section of country where 
it lies, indicates a removal from its original bed; while the inti- 
mate connexion of the metal and matrix, and the complete en- 
velopment of individual masses of the copper by the rock, point 
to a common and contemporaneous origin, whether that be re- 
ferable to the agency of calorie er water. This conclusion ad- 
mits of an obvious and important application to the extensive 
strata of serpentine and other magnesian rocks found in various 
parts of the globe! ‘The Ontonagon river at this place is broad, 
rapid and shallow, and filled with detached masses of rock out of 
place, which project above the water, and render the navigation 
extremely difficult during the summer season, The bed of the 
-* This, however, is no uncommon ae COW of native copper.--Ep. 
+ See Bruce’s Mineralogical Journal, p. 124, 218, 
{ See Henry's Travels and Adventures, p. 205. 
_. § Philip’s Mineralogy. 
, river 
