The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1922-07-06


at any rate these great areas of beds
to later rocks convince us they be-
Ionged to the earliest period Of sedi
mentation. They have suffered and
withstood various movements and
agencies that have attacked the
earth's crust in the intervening 500
million years but have become some
what changed as consequence. They
were originally sedimentary beds Of
shale. limestone, sandstone and in
termediate variations of them; but
now we class them as metamorphic
rocks called schists, States argllites,
quartzites, marbles and the like. Heat,
pressure, distortion and hot water
have conspired to recrystallize many
of the minerals and they present a
vastly different texture, color hard
ness and general appearance than
their original sediments during the
first period Of existence
Character Of the Rock.
The biologists call these rocks the
Algonkian group and the area lying in
north Idaho, Montana and Canada
probably represents the largest area
Of their kind in North America. The
greater part of these older metamor-
phic sedimentaries are known as the
belt series.
Many areas Of igneous rocks are ex-
posed in this region. They are main
~ GRANTEES and similar rocks that
cooled from molten magmas which in
truded these older sediments at date
long after they were deposited. Many
of these igneous exposures result from
the stripping away of the everything
belt series by the age long erosion Of
running water and the ice sheets
In the days of the intrusions OF
these great bodies of molten magma
into this everything crust sufficient dis
turbance occurred to change the orig
inally horizontal or nearly horizontal
position of this great mass of old sed-
imentary beds.
Resulting from the great tensions
and compressions' applied to these
fairly resistant strata. great folds
particularly resistant to the forces.
breaks would occur permitting one
side of an area 10 drop below the op-
pOsite side. OFTEN when this force
was continued one great layer would !
slide over the other part of itself !
which had been broken off. These
breaks which are common throughout /
the belt series are called faults
Many of the faults in this country /
are remarkable for their vast size and
indicating the tremend- /
ous stresses that have been so i'm |
portant a factor in developing the
geologic and photographic appear
lnce of the region.
Four great photographic provinces /
are contained in or border upon the
area of this description. They have
been produced by the faulting and /
folding of the older belt rocks by
great intrusions of magma and the |
crystal disturbances of the same time
They are represented by two noun
tain ranges and two great valleys.
Known respectively as the Cabinet
'ange, Purcell range Purcell trench
md Kootenai valley.
Cabinet Range.
This range begins at Bonners Ferry
md extends southeastward through
Montana to the Flathead river and
locke creek. II is bordered by the
'urcell trench and part of the Clark
Cork valley and is cut into two por-
ions by the deep trench of Bull river
nd Bull lake The western region /
outheast Of Boomers Ferry is great Z
'lateau that is dissected. or cut up {
" stream erosion and glaciation.
Hardness of the strata and recur- '
ent alpine glaciation has effected 5
errated details which are represent 7
d by highly picturesque sculpture. s
cotchman peak represents one of the e
lost majestic features of this land e
cape. Some parts of this scenic Il
lnge. lofty and rugged in their topo- s
raphy, are very impressive and con- {
lin living glaciers at heights of 5000 A
'et This range contains only two o
'latively small areas of granite.
Purcell Range. t.
That part of this range which lies n
Idaho is defined by the flow of the o.
ootenai river All the mountains to cl
e east and northeast of Bonners a
erry belong to this photographic s,
ovince. This range in turn is divid- ii
by the Moyie and Yak rivers Ell
'wng into the Kootenai valley. Like al
g Cabinet range this area was orig
ally high plateau. and now rugged
I'd irregular due to the same ire 81
stible erosion agencies. The peaks a
e of nearly the same height and ID
ne are conspicuous. The rocks are 81
of the belt series and their resist la
zee has permitted heights of 1900 oN
et TO be maintained on this lofty 81
ssected plateau. re
The Purcell Trench. m
This great depression extending for Dc
ndreds of miles in a north and &C
nth direction serves to cut the st
eat Rocky Mountain system i'm ii,