Mineral Point tribune. [volume] (Mineral Point, Wis.) 1854-1858, 1854-09-06
For the Tribune.

veins are true mineral veins.
The absorbing inquiry with all is, viii these
lodes continue productive in their downward
course. am aware that the conclusion adopted
by all Biologists who have visited Us, and conse-
qaently the impression made on the minds of this
community Is, that this sandstone that underlles
our limestone beds is non netalllfcrous, and in il
our lodes cannot be otherwise than destroyed
Bat 10 me- II is an unsettled question, whether any
rock IN the strictest sense and under all circunl
stances can be said tc be non netallilerous What
ever may be the conclusion OF scientific
this subject, the practical miner whose home is
IN the rocks, whose business it is TO investigate,
whose interest ii is to collect facts, has long been
convinced that the prominent features of good
mineral ground consist no more in the class of
rock to which il belongs than to the metamorphic
action TO which it has been exposed or in other
words, certain class of rocks, which under ordi-
nary circumstances, may be said to be metal
herous, when acted upon by certain physical for
ces, become good mineral bearing rocks. These
facts are evident in the Accommodations of all Geo
logical ages, and may be well studied in the exca-
Vatlons made Ill all good mining regions. This
truth is as evidently set forth in the sandstone beds
as IN any other rock. The man who has paid par
tcular attention 10 the notifications of rocks is
aware that il is singular thing to find sandstone
dwlndiing into quartz rock, quartz rock gradu-
ally passing into its ordinary sandstone character
leaving US the most indubitable evidence that their
age and origin is the same. Now while the sand
stone is set down to be non-metalilerous quartz
Is known to be the most genial matrix of ore To
know the cause or causes by which these changes
have been produced, is of the utmost importance
to the practical miner, and should never be lost
sight of in determining the value of a mining dis
trict, inasmuch as the are generally found
in these altered modified rocks. 1t would
doubtless be far beyond my sphere to ATTEMPT
to define the various causes by which these chan
ges have been produced; nevertheless NAV col
lect and use TO explain any Geological phenomena
those facts that may be found in the sphere of the
practical man. II is fact unquestionable to ey-
cry observing miner, that close proximity to gran
lie or other rocks of igneods origin is one cause
by which these changes are effected If we travel
through the mining regions of Devon and Corn
wall, England we shall find most of the ores of
the useful metals at or near the functions of the
granite and the sed!mentaTy rocks, and more es
pecially where these sedimentary rocks have been
considerably altered or modified in consequence
of their close proximity to rocks Of igneous ori-
gin. do not claim for the basis of this. sand
stone, granite, or any other isneous rocks But
DO think tor reasons watch might be given that
there are places in this mining region where its
influences have been and perhaps are being felt
and TO this W IcIb-IaSS ;L,,+o
some Of the features of our mineral bearing rock.
Another cause which holds prominent place
among those by which these changes are effected,
is heat, and whether this heat arises from large
masses of lgneous rocks adjacent thereto or from
suberraneous elevated temperature through crew
ices, the effect doubtless the same: another
cause by which sandstone especially, is changed
and nodihet l. the introduction of silica after
It's original deposit II is an established fact with
Biologists that silica, if finding its way to sand
stone beds IN solution, has the property of des-
semnatng itself amid the pores of the rock
though the rock may be hard and compact Hence.
the sandstone being changed TO quartz, in many
places, is attributed to this cause by the ablest
Biologists of the day. What binders the sand
stone here then, from being effected by some oil
these or similar causes, and if so, why not be
metaillieTous whether it is thus effected or not
one thing is evident and that is, the upper masne
sian limestone, that class of rock to which our
mining operations have hitherto been confined
has been so changed and effected in the vicinity
of the crevices by some cause, as TO nearly oblit
crate (to use the language of Professor Daniels
ITS usual characters Why not the sandstone be
effected also Z H. however, this sandstone should
remain unaffected by these causes, is there no pos
sible way by which our lodes NAV be saved from
death and destruction when passing through this
so called dead and barren rock? If ours are
true veins, these forces referred to in a former
communication, would doubtless derive their
power from below the sandstone. Ifso. we mioht
expect to find the san .stone broken in places
and lis fragments deposited intrusive rocks
along the lode just as we find granite or frag,
ments OF other igneous rocks thrown up and de-
posted in lodes that are traversing sedimentary
rocks. This is by no means an anomaly in true
mineral veirs; and to me, satisfactorily develop
ed in these lodes at the Dreadnaught mine Nv
first visit to this mine was in company with a |
man who had been acquainted with its former |
and the materials with which it was composed. |
ne handed me rounded piece of sandstone When
remarked 1t was sandstone, he said if this was |
sandstone he could show large quantity of
1t. He took me few feet farther west. and |
there were seven or eight large pieces, some oil
them three or four thousand pounds Up to this !
time they seemed to have passed unnoticed. II |
Is true, on these the rude Indian NAV have SAT |
weary and latigued, but in these rocks he saw
nothing more than resting place BY these too
the miner may have passed when out in quest of
mineral wealth, regarding them only as way
marks to guide him back to his lonely cabin
but however void of interest they may be to the
red man or the man whose mind remains nntoncb |
ed by the expansive power Of science, to the /
scientific man, they interesting, they are i'm
poFtant. They furnish subject on which the |
noDieSt powers of his mind may find full exercise
lnese large pieces of sandstone on the surface of
mr. -of, 49,,