64 On the Paragenetic Relations of Minerals. 
blende, are remarkably frequent in it,and also the arsenio-sul-. 
phurets and arseniurets, perhaps also withantimony. Itisthese 
minerals chiefly which gave to the lodes their distinguishing 
characters in their original perfect state. To these must be 
added several of the above mentioned oxidized minerals, 
such as tin ore, dyschorite, &c., while other oxides are pro- 
ducts of decomposition. In the upper part lodes certainly 
present a physiognomy differing from that of their original 
state, because the products of decomposition are situated there, 
sometimes predominating, and either in their own forms or 
as pseudomorphs. Adding to these the products of gradual 
alteration, such as steatite, it is evident that the present 
condition of certain depths of lodes varies greatly from the 
original. Substances coming from the surface have certainly 
taken part in the decomposition, and the influence of the 
adjoining rock is not to be doubted. 
The substances found in vesicular cavities show what may 
result from lateral secretion alone ; but there is a great 
difference between these substances and those found in lodes. 
What has been said of these latter is sufficient to lead to 
the conviction that the greater part of them must have come 
from the interior of the earth, and not from the side or above. 
We may indeed imagine the oxides to have been brought 
up in a solution as springs, and precipipated by sulphuretted 
hydrogen and arseniuretted hydrogen, but it is more probable 
that they were introduced into the fissures in thisform, and the 
question may justly be raised whether there has not been more 
introduced into the rocks from lodes than from the rocks into. 
the lodes. We have already seen how astonishing is the action 
of a younger rock upon an older. The old belief of miners 
that the lodes are richer at greater depths has therefore, in 
general, a good foundation. It is possible that where con- 
siderable decomposition and alteration has taken place much 
has been carried away from the lodes through fissures, in 
consequence of which they may very probably be more yalu- 
able at a depth than where the minerals are no longer in the 
original state. It is, moreover, in all respects, easily con- 
ceivable that the sulphuretted and arsenious minerals should 
be farther from the surface than those which are oxidized 
