The Anaconda standard. [volume] (Anaconda, Mont.) 1889-1970, 1898-02-09
It Will Provide Data for Future
Topographic Maps.
FOREST RESERVE PLANS
The Economic Survey of the Mining
District OF Butte-Information in
Relation to the Methods
of Ore Deposition.
Washington Bureau of The Standard,
No. LII q Street ". w. |


rector OF the geological survey, is just
issued. 1t contains a great deal of
matter of especial interest to Montana
people. The director says the sur
vey of the northern portion of the
boundary line between Idaho and
Montana is the first work of the kind
assigned to the geological survey, and
IL will be done in such a manner as
to insure the required accuracy for the
boundary line and provide data for fu-
ture topographic maps in the vicinity
of the boundary. This Will be accom-
plished by having the control of the
position of the boundary established
by triangulation. 1t is also provided
that the triangulation shall be extend
ed southwark along the line OF the Bit
er Root mountains The plan Tor TINS
survey was approved by the secretary
of the interior and the work was begun
the last of June.
Provisions has also been made for
the survey of the forest reserves, an
appropriation of $150,000 being made
for the purpose The plan of opera
lions for this work was submitted to
the secretary early in June, and before
the close of the month surveying par
ties left Washington to begin the work
in the Black Hills reserve of South
Dakota the Teton and Big Horn re-
Flathead and Priest river reserves of
Montana, and the Washington reserve
of Washington. Plans We're also for
mulated and approved for an exami-
nation of the distribution of the for
ests in the same reserves. 1t is antici-
pated that before the close of the field
season sufficient data will have been
secured in relation TO the settled areas
of the reserves embraced in the eXecu-
tive orders and proclamations which
were by congressional action suspend
ed until March /, 1898 to enable the
department to form an opinion, based
upon maps and notes, as to the popu-
lation and Improvements that are in
Guided within the areas of the re-
serves; also as to the distribution of
the forested and agricultural lands.
During the year S. r. Emmons and
w. II. Weed Of Helena co-operated in
field work in Montana. The principal
work was the economic survey of the
mining district of Butte, which, as
represented on the Butte special map,
covers an area of % square miles. The
work was. however, extended far be-
yond the limits of the map. The areal
geology-that is, the outlining of the
various formations appearing on the
surface-was the special work of Mr.
Weed; while Mr.. Emmons. assisted by
c. W. Tower, had charge of the under
ground observations in the mines. The
underground work consisted in trac-
ing the veins in depth as far as deVel-
oped by the workings of the different
mines, and studying their mode OF for
nation. their mineral composition. the
nature of the fractures along which
they have been deposited. and the par
agenesis of the different vein minerals.
; In order to ascertain the age OF the
different eruptiVe rocks and the ofo-
graphic movements which have pro-
duced the vein fractures of the district,
i. ,.1 20. nd
naissance survey to the periphery of the
great granite body of which Butte is
approximately the geographic center.
For this purpose Mr.. Weed made pre-
liminary examinations throughout an
area about so or 90 miles square, and
Mr.. Emmons personally examined some
of the critical points of contact of the
granite with the surrounding sedimen-
tary formations. as thus determined by
Mr. Weed
In addition to the general field work,
MIR. Emmons and Mr.. Tower made hasty
studies of important mine developments
in the periphery of the granite region in
which Butte is situated. Among the
more important of these We're the May
flower mine in the Tobacco Root noun
tains southeast of Butte. the Cable mine
near Anaconda and the Elkhorn mine
near Boulder
The director says 1t is yet too early
to indicate the results of this work,
whether scientific or economic, as
large proportion of the results obtained
by underground work in general are ar
rived at only after considerable
amount of office work has been done,
The facts determined in regard to the
Butte district are:
Cd The basic granite. the Oldest coun-
try rock Of the region, is post carbon
ferrous and possibly more recent in age.
81 The acid aplitic granite, which
A. Il
a country rock, is a later eruptive. prob
ably an alternative phase of eruption
of the same magma.
ca The big Butte is the center Of
eruption, or "a volcanic neck whose ma
terial has been poured out since the
veins carrying gold silver and copper
were formed The rock of which 1t is
composed will probably be found not to
differ essentially in chemical compost
tion from the granite rocks In which the
economically valuable ores occur The
date of this eruption was probably that
of the effusiVe rhyolite which borders
the district ON the northwest.
"a There is evidence in the mines of
two general periods of dynamic move
ment by which the rock fractures that
admitted Undertaking solutions have
been produced. also. that there have
been successive concentrations of me-
tallic minerals after these movements.
The investigation, according to Mr.
Walcott. was undertaken too late in the
history of the district To enable Messrs
Emlons and Weed To make their work
of much immediate practical advantage
To the mine owners. Ii is probable, how
ever. that the mapping of all the veins
and the discussion of the fracture sys-
TENS and of the probable methods and
succession of deposition of metallic min
erals. will inure TO the advantage of the
miners in ways that cannot at present
be seen. The great and certain result OF
economic Importance TO the mining in
dustry in general will be the accurate
delineation OF the various phases OF ore
occurrence in this remarkable district
which ranks in Importance With thar nj
Leadville and the ComstoCk
The reconnaissance examinations Of
other mining districts and regions
made during the summer. While not
sufficiently refined or detailed To ius-
tify the publication OF individual re-
ports, have materially enlarged the