The silver state. [volume] (Winnemucca, Nev.) 1909-1925, 1910-07-19
GEOLOGICAL FORM
ALTON OF NATIONAL
Geological Formation Of National II
Brief.
(By 8. K. BRADFORD.)

(By s. X. BRADFORD.)
The formation appearing ON the sur
face in the north end of the district il
eruptive, while from Canon creek
south, more or less sedimentary rocks
crop through. These are to q certain
extent covered with numerous volcanic
flows To the north of Canon creek
there are on the surface many frag
ments of sedimentary formations, es
pecially lines, undoubtedly brought uI
during the eruptions which brought uT
assuring and dyking Of the entire dis
trict.
These sedimentary rocks would seem
to indicate that the base of the entire
district is sedimentary.
The igneous formations of the dis
trict seem to have trend of about
north 90 degrees west and south 90
degrees east.
Apparently Buckskin mountain was
the center of the eruptive flows of the
district. One, at least, can be traced
to Buckskin. Charleston Hill shows al
least two volcanic throats, and others
appear at various parts of the dis
trict.
There were numerous flows at vari
GUS times, which in turn have been
fractured, and new throats appearing
have given vent to flows covering the
original flows While other flows ap.
peared in form of intrusions, which on
reaching the surface have in turn
spread out over the surrounding area
making it almost impossible to distin
guish between the flow and intrusion,
the geological system of the district
is very complex, and it will take
months of study and observation to
work out a comprehensive map thereof
The ores are in well defined fis-
sures within an altered and highly
mineralized andesite. This formation
is cut with numerous intrusive dykes
which have spread out over the imme-
idate surrounding area, often leaving
little, or none at all, of the vein-enelos
ing andesite exposed 1t is very puz-
zling to the prospector to decide when
he starts work, whether he is sinking
in a flow, or whether he has encounter.
ed a dyke.
In Charleston Hill some of the dykes
cut the vein, while others are cut by
the vein, showing that some of the
dvkes antedate the fracture and that
others were subsequent to the last re.
opening of the fssure.
IL is to be hoped that the Geological
Bureau Of the United States will send
in a competent corps of geologists to
make a thorough study of the district
and thus save the prospectors hundreds
of thousands of dollars in useless and
absolutely worthless exploration.
Thousands of feet of tunnelings have
already been made in the various
later, and Of course upper, glows OF
the district. This not only is a waste
of the investor s money, but he and
his friends will ever condemn mining
for the failure; whereas there is moth
ing at fault except the gross, assinine
ignorance of the investors and manag
ers. 1t is safe to say that nine-tenths
of the failures in mining are due TO o
total ignorance of geological forma-
tions.
This makes il hard to raise money
to open meritorious mining enter
prises.
The intrusions consist principally OF
diabase, rhyolite, dacite, diorite and
andesite, all more or less altered; and
their prevalence is about in the order
named.
The surface of the district is cover
ed with wash, except in the case OF
the very latest flows. which seem tc
have been of such recent origin thai
eing altered, they have withstood al
the latter erosions of the district. III
fact, there is very little evidence OF
erosion in the entire district. This fac
alone makes it impossible to form al
accurate idea of the geological system
There are no doubt numerous faults
both vertical and horizontal, but fol
reasons above stated there is little L
be seen on the surface to guide one II
the study thereof, The underground
workings have so far shown little fault
ing.
One peculiar feature of the mos
prominent andesite flow, or dyke. a
il may later prove to be, is the fac
that it contains more or less silevr ant
little gold in spots outside the mail
lode or vein.
The deposition of the gold is probab
ly similar to that of the Goldfeld dis
trict, with the exception that, Will
both were deposited in the form o
chutcs or pipes, the National chute
occur so far in the main northerly an
southerly fssure.
No doubt development will in tn
future show values in the cross MS
sures, and possibly ehutes of ore wi
be found along the various intrusiv
dykes. as at Goldfeld.
There can be no doubt that the S,
called high grade, that is, electrm
ore will be found in all those fssurt
made at the same time as the Charlie
ton Hill fissure. There are hundreds {
assures in Charleston Hill made, I
doubt. subsequent to the Charlesto
Hill vein, which contains a differeI
ore In fact the naturalization is e.
tirely different, and the electrum OF
features, so far as opened, are missin
An erroneous impression in referen'
to National mines universally obtai
Because of the very unprecedented an
uniformly high values of the so II
treated National ores, the idea Uni
there are low grade ores in the a.
trict has obtained general circulatio
To be sure, two little mills capable
treating, one 800 pounds day and .
other 600 pounds, based on a contin
ous and steady run of gasoline G