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The
Swiss
Alps
are
only
the
western
par
of
an
immense
mountain
system
which
runs
across
the
European
continent
from
Nice
to
Vienna.
The
deep
valley
of
the
Rhine
and
Rhône
divide
the
Swiss
Alps
into
two
subsystem.
The
Northern
Alps
gradually
flatten
off,
first
into
the
Central
Plateau,
on
the
other
side
of
which
rise
the
Jura
Mountains.
The
Southern
Alps
tower
above
the
Po
Basin
of
northern
Italy,
forming
an
almost
insurmountable
obstacle.
The
Northern
Alps
are
cut
through
by
the
valley
of
the
Reuss,
which
runs
at
right
angles
to
the
Rhine
and
Rhône,
and,
like
them,
has
its
source
and
headstreams
in
the
St.
Gothard
Massif.
St.
Gothard
is
the
of
a
real
Alpine
crossroads
opening
up
to
the
four
points
of
the
compass.
The
Swiss
Alps
have
about
50
peaks
of
over
13,000
ft,
the
greatest
concentration
of
high
mountains
in
the
European
system.
Used
to
dealing
in
millions
of
years,
the
geologist
looks
upon
the
Alps
with
a
certain
degree
of
indulgence,
for,
geologically
speaking,
they
are
extremely
young.
They
were
formed
during
the
Tertiary
period,
and
the
process
was
very
simple.
it
was
a
logical
step
in
the
geological
development
of
the
earth
Around
its
shores
rose
land
masses
whose
rivers
carried
debris
into
the
sea.
This
debris
settled
on
the
sea
bed
and,
under
the
enormous
pressure
of
the
water,
was
gradually
transformed
into
sedimentary
rock:
marl,
sandstone,
and
limestone.
But
soon
the
earth’s
crust,
and
with
it
the
sedimentary
rock
layer,
was
folded
by
a
tremendous
thrust
from
the
south.
The
folded
rock
rose
higher
and
higher
,finally
emerging
above
the
water
and
forming
islands.
But
the
pressure
continued,
and
the
rock
folded
over
towards
the
north,
forming
overlapping
“pleats”,
or
overfolds.
The
Alps
were
now
born,
but
they
were
to
go
through
further
startling
changes.
Erosion
began
to
attack
these
extremely
vulnerable
masses
of
rock.
The
great
rivers
cut
their
way
deep
into
the
rocky
layers
and
transported
the
sediment
into
the
sea.
This
material
covered
a
large
area,
the
lightest
elements
drifting
far
beyond
the
coasts
the
soft
Tertiary
sandstone,
or molasse,
under
which
were
layers
of
marl,
sandstone,
and
conglomerate.
But
magma,
the
molten
material
beneath
the
earth’
crust,
also
played
a
part.
It
exerted
immense
pressure
on
the
Alpine
system,
fracturing
its
limestone
crust,
and
revealing
the
ancient
crystalline
substructures.
Granite
was
the
rock
most
frequently
forced
upwards
from
below.
Sometimes
it
appear
together
with
gneiss,
the
most
common
form
of
metamorphic
rock.
Tertiary
limestone
are
the
most
common
rock
in
the
north.
Heavily,
eroded,
and
rich
in
fossiles,
they
sometimes
enclose
minerals,
which
give
them
surprising
tints.
They
endow
the
surface
of
this
region
with
its
characteristic
appearance.
Thus
the
Alps
were
formed
by
horizontal
continental
thrusts
and
vertical
magmatic
outbreaks.
Erosive
activity
started
as
soon
as
the
land
masses
emerged
from
the
sea
and
has
never
ceased.
Erosion
is
a
sculptor
of
planetary
stature,
never
ceasing
to
work
on
the
granite
to
form
all
kinds
of
bizarre
shapes,
and
on
the
limestone
to
carve
out
steep
cliffs,
or
jagged
ridges;
transitional
shapes
of
all
kinds
are
to
found
where
harder
and
softer
rocks
occur
in
the
same
area.
Erosion
has
many
agencies,
apart
from
the
simple
action
of
wind
and
water.
Rain
seeping
into
small
cracks
and
then
freezing,
for
example,
can
split
the
rock.
And
thermal
fluctuations
leading
to
the
expansion
and
contraction
of
rock
can
also
ultimately
have
an
erosive
effect.
The
slow
death
of
the
mountains
is
often
dramatically
emphasized
by
violent
landslides.
The
rubble
is
away
by
rivers
and
accumulation
on
the
sea
bed.
And
perhaps
in
many
million
year’s
time
a
new
cycle
will
begin.
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