Western news and the Libby times. [volume] (Libby, Mont.) 1920-1933, 1933-01-05
Libby Map
Is Ready For
Distribution
Gives Interesting, Valuable
Information for Miners
and Others.
PREPARED BY
DR.. RUSSELL GIBSON

This newspaper is in receipt of a
letter from DR.. Russell Gibson, who
has conducted geological work for the
government in this area for the past
two or three years DR.. Gibson en-
closes circular which states that a
map of the Libby area, prepared by
DIR. Gibson, is now ready for dis
tribution. Those desiring copies of the
map should write The Geological Sur
vey, Washington, D. C., enclosing 10
cents for each map desired, and max
ing all rernittances payable to the order
of the Director of the Geological Sur.
vey
The circular gives the following IN
teresting information relative to the
map of the Libby area
Map of adjacent parts of Lincoln
and Sanders counties. This map shows
by contour lines the oonfiguration of
a considerable part of two main ridges
of the Cabinet Mountains, several of
whose peaks rise to attitudes of 4,949
to 8,712 feet above sea level These
ridges are very rugged, and their
flanks are gashed' by deep, narrow
gorges. The Kootenai River, tribu-
tary Of the Columbia River, in the
most southerly part Of its course with
in the United States flows westward
across the northern part Of this area
at an altitude between 2,l00 and 1,875
feet and has cut transversely through
the mountain ranges in deep can
yon that separates the Purcell Noun
tains on the north from the Cabinet
Mountains on the south. The Clark
Fork Of the Columbia River. here
about z,25o fset Ahoye ~ level. flows
northwestward acrsss the southwest
corner Of the area in a broad but
steep-sided valley between the Cabinet
Mountains on the north and the Bit
terroot Mountains on the south. An
anomalous feature Is through val
ley between the two ridges Of the
Cabinet Mountains that connects the
Clark Fork Valley with the Kootenai
Valley. Bull Lake lies in this valley
Just north Of the low pass, which Is
on a gravelly flat 2.340 feet above the
sea. The outlet of the lake is north
ward by Lake Creek to the Kootenai.
South OF the pass the valley drains
through the Bull River to the Clark
Fork. Two small glaciers are shown
on the northeast flank Of Snowshoe
Peak and one on Elephant Peak. The
configuration OF many Of the gorges,
as shown by the contour lines, indi-
Gates that they were once occupied by
large glaciers that extended from no
table amphitheaters or smoothly
rounded eirques high In the mountains
for miles down to the main valleys,
This was during the great ice age.
Some OF these mountain glaciers were
tributary to lobes of the great Cordil-
leran ice sheet, which advanced south
ward one or more times from the north
into this and adjacent parts OF Mon
tana, Idaho, and Washington. One Of
these great lobes or tongues Of ice ex-
tended southwark nearly, if not en-
tirely, through the Bull Lake Valley
to the Clark Fork Another moved
southwark up the broad valley Of Lib
by Creek. Still another great lobe ex-
tended southwark along broad trough
west Of this area in northern Idaho
TO the region Of Pend Oreille anc
Occur d'Alene Lakes and completely
blocked the Clark Fork Valley neal
the present Mentana-Idaho State linz
with an ice dam 1000 feet in height
This obstruction pended the water IL
the Clark Fork Valley and its tribu,
taries for distance Of $50 miles, form.
ing lake known to .geologists as gla
cial Lake Missoula AS the ice dan
melted the level of the lake was grad
ually lowered, and IT was final.
drained. AS the ice melted in the val
leys Of Libby and Lake Creeks am
in the part Of the Kootenai Vale.
within the United States, the waite
was similarly pended to the height Q
the lowest passes leading southwark
One Of these passes was that jus
south Of Bull Lake, where the top {
the filling left in that valley had
first an altitude Of about $500 fee
In all these temporary glacial lake
and especially in the Kootenai Vale.
considerable thiclnesses of thin
bedded lake silt were deposited on to
Of the glacial drift AS shown by Ii
map, there are extensive terraces abos
$500 feet above sea level especial