The Helena independent. [volume] (Helena, Mont.) 1875-1943, 1893-05-04
A LECTURE IN GEOLOGY.
Prof A. D. Churchill Tells the Jury
About the Marysville
District
The Drum Lummon Vein Is a Fis-
sure Averaging Thirty Feet
In Width.
The Orc Bodies Are Large and Rioh, but
Are Quite n Distance
Apart.

The Orc Bodies Arc Large and R,oh, but
Are Quite N Distance
Apart.
Prot. A. d. Churchill. of Helena. one'of
che experts for the 81. Louis Mining and
Milling company In it's case against the
Montana company, limited, treated the
court and jury yesterday forenoon TO a
lecture on the geology Of the Marysville
dist'i His observations there have OK
tended over a period OF four years. and
we're with a view to finding what 10 called
the main, or whnt NAV be called the main
country rock in which the vein may OCCUR.
II made a tour" he said. "of several miles
Mt diff srent times, and / find that the basin
in which the town Of Marysville is located
appears to be somewhere near the center OF
the granite; what you might call the
granite nucleus Of the district In which the
Drum Lummon lode ocnuts. In the exam
inntion of this granite 1 find hat IL 10
rather hne-grained, especially where it IL
observed at a distance from the lode II is
unchanged in its character, and ! ind 1t
consisting of quartz aud other snail crys-
tails. and feldspar and mica, md likewise
some horn-blends in small particles. As
this granite approaches the vein the usual
change takes place. I also find
granite which IL evidently de-
tached from the main granite
formation of the country. and .some
one or two instances in which I would say
that the granite. that is what is called the
intrusive granite. Is quite metarmorphcsed.
nnd 10 really a granite dixie. The other
general feature OF tho country 10 this. that
there has been deposited upon the rock
that il superinfuaed npon the granite. what
you might call shales or slate. These arc
impregnated to a considerable extent with
mngnesin and mny be called magnesium
shales or slate. would hardly call them
shists. because they are not In that condi-
tion. This granite or nucleus seems to
have a number of ridges in it in o uniform
slope from the center, md the states being
originally deposited upon that in a hori-
zontnl position. where the country may
have been fissu.ed by any vein. either the
Drum Lummon or others and outs through
this wall, 6f course intersectinR both tho
slate and the granite. and that accounts in
part for having granite on ono side Of the
vein Of the Drum Lummo and not ON the
other. ! have given a more or less careful
examination OF the Drum Lummon vein
10 determine its size and character for
about four years.
Prot. Churchill explained the vein and
its connections with the st. Louis ground
and workings and with the workings Of tho
defendant company ms follows: 1.-THE Drum
Lummon, SO cnlled, which passes through
both tho Montana company property and
the 81. Louis property is q fssure. and 1t Ia
long, strong and large, not unusually large
for the length that it has been exposed. It
width as far as opened and It will reach
probably seventy-fve feet in places. and
PERHAPS there are rlaces where it might DO
even wider than that. and then again IL will
pinch down to probably something less
than twenty feet in width. II isl assure
suit of that has been the crushing Of the
material within the vein. and the
large amount of clay sclvege formed
upon the foot and hanging
wallis from that movement showing stria-
tions upon the foot and hanging walls.
a distance apart, and between those large
ore chutes we find ground which is practi-
crlIy barren from the foot to the hanging
wall. This barren material is composed OF
quartz near tho ohutss. That 10 to say the
chutes seem to flag out, as they say. toward
VIC hOuVu ANU IuA lNtO Il WAlt0s AhVu DATI0u
quartz, and this gradually fades into the
vein filling that may be present at that
portion of the lode, and where this change
takes place We find especially where the
matrix of the vein 10 shAles that form of
quartz takes the form to butte, aNonsidera.
which means that this vein WAS not filled
entirely as many assures are supposed
to be filled by s9lptions. gradually
crystallizinR out from the 4sidea of the vein
and finally filling NJ in the center. but a
large number OF these chutes. and in my
opinion the bulk of them, hive been
formed by mineral replacement. I have
one or two specimens which I will get at
later in which the quartz is shown in the
form of the slatea or shale which occur in
the vein. l mean the somewhat changed
shale. This is IN evidence in nv mind.
osmosc formation. On the other hand /
believe in the lower levels OF the mine
where the quartz ia very compact and some
what barren that that was filed up out of
the ore by direct mineral solution. Tho
ore bodies occur in both foot and hanging
wallis. that is to say, You will find one
chute on the hanging wall and ono on
walls Of the vein l find them
quite regular. I find that the general
heavy motion of the vein appears to have
been mp and down rs shown by tho zorro.
U0tlOn6 OH tue 1901 anu hanging Walls, ana
that this movement has been about fifteen
to twenty-five degrees further south from
the vertical on tAe dip. That 10 to say. II
you take a PROJECTION Of the situations and
~cotrooationa on both the foot and hanging
walls you will find them corresponding to
ench other. and you will find that they will
make an angle on a vertical line of fifteen
to twenty degrees.
1.-THE is conclusive to my mind that the
hanging walls, 40 matter how far above
they may be, are of the same geological
rye. and that the lode includes the Drum
Lnmmon vein. l have seen spaces with
bulkhends and timbcrs. spaces together
forty feet in width where the ore chute
from the foot wall apparently approaches
the real hanging wall. There is another
evidence of tho manner in which this
vein was filled or formed. You
will find the ore chutes. where they pass
from the foot to hanging wail. for example,
tho Jubilee is on the hanging wall at one
place and on the foot Mt another. That is
10 say, thnt while they have almost a uni
TO n. dip on the strike of the vein they are
more nenrly vertical ~ a body. l find on
examining the foot and hanging wall OF tho
lode thi its entire lonGth that on
an average there is very much more
clay selvegs on tie hanging wall than on
the foot wall. The movement has been 40
great and the pressure 80 great upon the
hanging wall. and in addition thereto there