60 
THE GEOLOGIST. 
very easy to smelt. However frequent copper may be, tin is of rare 
occurrence. Thus the only mines in Europe which produce tin at 
the present day are those of Cornwall, in England, and of the Erzge- 
birge and Fichtelgebirge, in Germany. 
But the question arises whether previous to the discovery of 
bronze, man, owing to the great rarity of tin, may not have begun 
by using copper in a pure state. If so, there would have been a 
copper-age between the stone- and bronze-ages. 
In America this has really been the case. When they were dis- 
covered by the Spaniards, both the two centres of civilization, Mexico 
and Peru, had bronze composed of copper and tin, which was used 
for manufacturing arms and cutting-instruments, in the absence of 
iron and steel, which were unknown in the New World ; but the 
admirable researches of Messrs. Squier and Davis on the antiqui- 
ties of the Mississippi valley* have brought to light an ancient civi- 
lization of a remarkable nature, and distinguished by the use of raw 
virgin copper, worked in a cold state by hammering without the aid 
of fire. The reason of its being so worked Hes in the nature of pure 
copper, which, when melted, flows sluggishly, and is not very fit for 
casting. A peculiar characteristic of the metal, that of occasionally 
containing crystals of virgin silver, betrays its origin, and shows that 
it was brought from the neighbourhood of Lake Superior. This 
region is still rich in metallic copper, of which single blocks attaining 
a weight of fifty tons have lately been discovered. There was even 
found at the bottom of an old mine a great mass of copper, which 
the ancients had evidently been unable to raise, and which they had 
abandoned, after having cut ofi" the projecting parts with stone 
hatchets. t 
The date of this American age is unknown : all we know is that 
it must reach as far back as ten centuries at least, that space of time 
being deemed necessary for the growth of the virgin forests, now 
flourishing upon the remains of that antique civilization of which the 
modem Indians have not even retained a tradition. 
* Squier and Davis. — " Ancient Monmnenta of the Mississippi Valley." 
Smithsonian Contributions to Knowledge. Washington, 1848. It is one of the 
most splendid archaeological works ever pubhshed. 
+ Lapham. — " The Antiquities of Wisconsin." Smithsonian Contributions to 
Knowledge, p. 76, 1855. 
