Bonners Ferry herald. [volume] (Bonners Ferry, Idaho) 1904-current, 1922-07-06

geologist, School of Mines, University
of Idaho. Prof. Kirkham's article is
well worth reading and will be ap-
preciated by the readers Of the Her
aid. Owing to the length of the arti-
Gle it is necessary to publish it in
two sections and the second INSTALL
ment, which pertains more particular
ly to the geology of Boundary county
will appear in the issue of the Herald
of July 13-Editor.
There is a marked tendency among
non-technical and non-scientific
people such as are engaged in bust
nes, sundry professions and various
industries to ignore certain data
seemingly specialized and technical in
in nature which if approached and
properly explained would intrigue
their interest in the same fashion that
that it affects its technical followers
Geology is a subject. Its materials
are to be found everywhere. At every
hand we find people living constantly
in search of romance, to whom life
seems dull and uneventful, yet COM
pletely surrounded by mountains,
hills, valleys, streams, terraces, soil
and the like, the geologic history of
which when properly interpreted by
an expert geologist seems like a YER
liable fairy tale. The whole surface
of the earth's crust serves as an in
exhaustible library which the geo
logist examines and interprets volume
by volume. Boundary County and the
country contiguous to Bonners Ferry
must consequently have its volumes
OF uninterrupted and untold history
Previous to the writer's attempt to
sketch such a history it seems desir-
able to prepare his readers for better
understanding by presenting a brief
review of the geological premises that
could enter into such a history.
One may say that geology is a his
tory of the earth and it's inhabitants
that treats OF the rocks and materials
of the earth and the agencies and
various processes which have been
involved in their formation and ar
rangement Another phase of it in
terprets by the rocks, their fossil con
tents and structural attitudes, and the
various stages through which the
earth and the living inhabitants have
passed
The rocks and the materials Of the
earth are conveniently classed in
three groups:
The igneous rocks made up the first
group and owe their origin to the
cooling of the molten slag-like magma
made up of a mineral complex that is
forced into and through the earth's
hardened outer crust There are Of
course a large number of variations
in these igneous rocks but there are
three distinct classes into which they
can be grouped. The first group are
fine grained and show few crystals
since they represent magma that has
entirely pierced the crustal covering
and upon being suddenly exposed to
the air has chilled so quickly as to
prevent the arrangement of the vari-
Gus minerals into crystals. Basalt
is a common rock that is truly rep
resentative of this type of igneous
occurrence.
Opposed to the above is the form
alton of another type of igneous rock
Large reservoirs of magma slowly
eating and absorbing their way
through the OVERLAPPING layers of the
earth's crust often fail to reach the
surface before losing their heat
This magma receives no sudden chill,
but has ample time to cool and as a
consequence the various minerals
separate and and all segregate into
well defined crystals with certain
characteristics peculiar to the min
eral. The commonly known granite
represents an excellent type of this
igneous rock occurrence
The third igneous type represents
an intermediate stage between the
first two types and provides a type
of rocks which have a fine grained
texture similar to the basalt des-
cribed above but which also contains
crystals or phenocrysts. These rocks
are properly called porphyries They
are usually found as dikes, sills or
feeders to the flows of the first type
Of igneous rock.
Sedimentary rocks make up the
second great group. These rocks are
formed from various sized fragments
of all kinds OF rock material worn
and broken away by hundreds of
forces from the ever present land
masses which we call continents
This material once detached is carried
by wind or by the water of countless
streams toward the oceans. Some of
it may be deposited in the widening
of the river or in a lake; some may
travel along a mountain stream to be
deposited at the base of the mountain
slope in the form of an alluvial fan
or cone. By much the greater part
3 mill liz rl.1, h.,
sorted and left. The coarser sedi-
ments are dropped first and the finer
materials carried farther out; thus
three types of material are finally
graded out by this water sorting.
The gravel deposited close by the
shore eventually becomes compacted