372 
COPPER ORES OF NIJNY TAGILSK. 
parts only which were in contact with it the most crystalline and metallic, by the 
development at such points of the most powerful electrical action. 
We leaned, we confess, when on the spot, to this opinion ; but, after having 
read the memoir of Colonel Helmersen upon the origin of the magnetic iron ore 
of Blagodat (which we regret we were unacquainted with when we examined this 
tract), we are bound to admit, that the plisenomena at Nijny Tagilsk may possibly 
be explicable in accordance with his views, and that the metallic iron ore may 
have penetrated the pre-existing greenstone of the hill and thence have flowed as 
submarine lava or volcanic mud into the contiguous depressions. The facts that 
the ore expands in width, thickness and dimensions as it is followed into the lower 
parts of the valley, and that it fills up all the sinuosities of the subjacent rock, 
seem, on the whole, to favour this view, to the consideration of which we shall 
recur in the next chapter. 
Copper ores and great mass of Malachites . — In the adjacent cupriferous ground 
at Nijny Tagilsk, nests and veins of copper ore have been found in the hollows 
between the eruptive rocks ; and although the largest mass of cupriferous ground 
lies at some little distance (nearly an English mile) from the chief mass of iron ore, 
igneous rocks arise on all sides of it. Here, however, the matrix is very dif- 
ferent from that of the iron ore. Instead of overlying and associated clay, the 
copper ground is flanked on one side by a rock much resembling the schaalstein 
or bedded trap of which we have spoken upon the river Issetz, and which highly 
inclined and sometimes vertical, seemed to be affected by powerful faults as repre- 
sented in this woodcut. 
ROUGH VERTICAL SECTION OF THE COPPER GROUND AT NIJNY TAGILSK. 
54 . 
Copper ground containing lumps 
of limestone and other rocks with 
thin veins of malachite. 
