AURIFEROUS COPPER LODES. 
169 
walls very well defined. At the depth of thirty-five or forty 
feet, its extreme width is forty feet. No one can inspect this 
lode and be uninterested in the chemical changes that have 
taken place since the fissure was filled with metal. The first 
change which perhaps would be noticed, is the perfect destruc¬ 
tion of the original lode. Its gangue, which is quartz, is dis¬ 
persed through the mass of black oxide and gossan in part. 
The true, original walls are broken down, and the copper is 
extended laterally into oven-shaped cavities, in the soft adja¬ 
cent slate. The smaller oven-shaped expansions extend into 
the rock six or seven feet, the larger still farther. The smaller 
are three or four feet high, and as many wide, and as they are 
occupied entirely with the black oxide of copper and its gangue, 
the contents only require to be shoveled and screened, in order 
to be prepared for market. Three hundred tons of this ore were 
taken out from this vein in one month. The chamber, after the 
removal of the ore, presents an irregular shape. Its roof is 
more uniform from the existence of the layer of bell-metal ore. 
This vein presents its most remarkable feature only when we 
contemplate it in its original condition; when the iron, copper, 
and arsenic were in combination with each other, and arranged 
in the usual order. Now we find the copper in the form of a 
black oxide, occupying the lowest place in the lode. The iron 
forms a mass seventy feet thick overlying all the rest. The 
more volatile elements, sulphur and arsenic, have disappeared. 
The change is undoubtedly one which should be referred to 
molecular forces, representing in its effects the formation of 
nodules, septaria, and sometimes entire strata. 
Ducktown can boast of five veins, rich as the Congdon, and 
similar in structure. Here is, therefore, a peculiar mineral 
district, rich beyond any which had been explored, and yet 
there is nothing upon the surface which would lead a geologist 
or miner to suspect the value and magnitude of the mines 
beneath it. It is true that on the surface there are mounds of 
gossan, or the hydrous peroxide of iron; yet copper is never 
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