The
Niagara
Escarpment
is
the
most
prominent
of
several
escarpments
formed
in
the
bedrock
of
southern
Ontario.
It
is
traceable
from
the
Niagara
River
to
northern
Michigan,
forming
the
spine
of
the
Bruce
Peninsula
and
Manitoulin
and
other
islands
in
northern
Lake
Huron.
It
also
extends
into
New
York
State
and
Wisconsin,
roughly
encircling
the
Michigan
structural
basin
in
the
bedrock.
How
was
it
formed?
The
escarpment
formed
over
millions
of
years
through
the
differential
erosion
by
weather
and
streams
of
rocks
of
different
hardnesses.
The
Niagara
Escarpment
has
a
caprock
of
dolostone
which
is
more
resistant
and
overlies
weaker,
more
easily
eroded
shale
rocks.
Through
time
the
soft
rocks
weather
and
erode
away
by
the
action
of
streams.
The
gradual
removal
of
the
soft
rocks
undercuts
the
resistant
caprock,
leaving
it
standing
as
a
cliff
-
the
escarpment.
The
erosional
process
is
most
readily
seen
at
Niagara
Falls,
where
the
river
has
speeded
the
process.
The
Niagara
Escarpment
is
not
formed
by
faulting.
There
is
no
displacement
of
the
rock
layers
at
the
escarpment,
as
shown
by
study
or
rock
exposures
and
drillholes.
Additional
resistant
rock
layers
make
more
than
one
escarpment
in
some
places.
Also,
in
some
places
thick
glacial
deposits
conceal
the
Niagara
Escarpment,
such
as
north
of
Georgetown,
but
it
continues
underground
and
reappears
farther
north.
