374 
MALACHITE OF NIJNY TAGILSK. 
it, the surrounding matiix had been cleared away from its summit and sides ; and 
it our notes taken on the spot are accurate, the summit alone has a length of about 
eighteen feet and a width of about nine feet, an enormous bulging mass being exposed 
beneath, the extent or base of which was not fully ascertained. The whole of the 
surface, however, which had been uncovered was calculated to contain not less than 
15,000 poods, or upwards of halt a million of pounds of pure and solid malachite. 
The geological interest attached to this mass lies in the indication it affords, that 
the substance called malachite has been formed by a cupriferous solution which has 
successively deposited its residue in the stalagmitic form. “ Mutatis mutandis,” 
this mass has only to be viewed as formed of calcareous spar, and it presents every 
one of the features so well known to those who have examined stalactitic grottos 
with their stalagmitic floors in the clefts and caverns of limestone, or still more those 
large masses of tufa which have proceeded from calcareous wells. Wherever a 
portion of the malachite has been broken off, the interior is seen to consist of a 
number of fine laminae (a fasciculus of radio-concentric globules), which invariably 
arrange themselves equably around the centre on which they have been formed, 
and are adapted to every sinuosity of the pre-existing layer ; here presenting a 
dark line, there a bright and light one ; just as the solution of the moment, the 
day or the hour, happened to be more or less impregnated with colouring matter. 
Besides round concretions, sometimes almost spherical, and also depressions of 
the surface, the under sides of this malachite are singularly analogous to that of 
any large mass of calcareous tufa, in presenting pendent, finger-shaped stalactites, 
which are also composed of concentric laminae. The external surfaces of these 
concretions are frequently covered with a black ore of manganese which usually 
falls off on being touched. 
When we examined this mass of malachite, much of the surrounding matrix 
had been removed, and it presented precisely the aspect of having been deposited 
in a depression of the limestone and schaalstein. On the whole, we are disposed 
to view it as having resulted from copper solutions emanating from all the 
porous, loose, surrounding mass, and which trickling through it to the lowest 
cavity upon the subjacent solid rock, have in a series of ages produced this won- 
derful subterranean incrustation. We would not, however, wish our readers to 
infer, that we have any authority for believing in the formation at the present day 
of such cupriferous stalagmites, though it is possible that nature mavin some tracts 
be stdl carrying on a similar process. Throughout all the great cupriferous region 
