The terraces of the Westfield River, Massachusetts


Davis, W.M.

American Journal of Science 14: 77-94

1902


T
II
E
AMERICAN
JOURNAL
OF
SCIENCE
[FOURTH
SERIES.]
ART.
Xiii.—The
Terraces
of
the
Westfield
River,
_Mass.;
by
W.
DAVIS.
(With
Plate
IV.)
1.
The
several
theories
of
river
terraces.
The
river
terraces
that
are
so
abundantly
developed
in
the
stratified
drift
of
our
New
England
valleys,
receive
scanty
explanation
in
the
text-
books
to
which
reference
is
ordinarily
made
for
accounts
of
such
forms,
and
are,
indeed,
not
exhaustively
treated
in
essays
of
a
more
advanced
character.
Their
most
significant
feature
is
an
arrangement
in
the
form
of
a
flight
of
steps,
of
unequal
tread
and
rise,
and
usually
of
unlike
sequence
on
the
two
sides
of
a
valley,
but
necessarily
exhibiting
a
less
cross-valley
breadth
between
the
terraces
at
the
bottom
of
two
opposite
flights
than
between
those
at
the
top.
It
is
generally
agreed
that
each
terrace
plain
is
the
remnant
of
a
flood
plain,
that
was
formed
during
the
process
of
valley-carving
by
the
river
that
now
flows
on
the
flood
plain
or
"interval"
between
the
lowest
terraces
of
the
series
and
that
the
terrace
fronts
or
scarps
have
been
carved
by
the
wandering
river
as
it
swung
laterally
on
its
successive
flood
plains.
The
slope
of
the
terrace
plains
down
the
valley
and
the
pattern
of
the
terrace
scarps
in
curves
concave
towards
the
river,
frequently
uniting
in
cusps,
give
convincing
proof
of
these
conclusions.
It
follows
that
our
terracing
rivers
habitually
had
a
greater
breadth
of
swinging
on
the
flood
plains
at
high
levels,
when
beginning
the
work
of
sweeping
the
drift
from
their
valleys,
than
at
the
low
levels
on
which
they
are
now
flowing.
The
special
point
that
needs
to
be
accounted
for
is,
therefore,
the
restriction
of
the
belt
over
which
the
river
swings
to
a
less
and
less
breadth
in
passing
from
the
initial
to
the
present
stage
of
terrace
development.
There
are
three
theories
which
offer
an
explanation
for
this
restriction.
The
first
and
most
popular
postulates
a
decrease
A.M.
JOUR.
SCL—FOURTH
SERIES,
VOL.
XIV,
NO.
sp.—ArGusT,
1902.
6
78
Davis—Terraces
of
the
Westfield
River,
21
-
ass.
in
river
volume
during
and
after
the
uplift
of
the
region
by
which
the
erosion
of
the
valley
was
prompted.
The
river
is
by
this
theory
supposed
to
have
been
so
large
when
terracing
began
that
it
needed
a
broad
space
on
which
to
swing
;
now
that
the
river
has
diminished
in
volume
it
is
relatively
enfeebled
and
is
contented
to
swing
over
a
narrower
belt
than
formerly
;
so
the
later
formed
terraces
do
not
undercut
and
destroy
those
of
earlier
date.
The
second
theory
postulates
successive
uplifts
of
the
region.
The
river,
revived
by
each
uplift,
wears
its
channel
beneath
its
previous
flood
plain
and,
on
reaching
grade,
begins
to
swing
laterally.
It
is
then
further
postulated,
sometimes
tacitly,
that
the
later
uplifts
have
succeeded
each
other
at
shorter
and
shorter
intervals,
allowing
legs
and
less
time
for
lateral
swinging
as
the
valley
was
worn
deeper
and
deeper.
2.
"Miller's
theory
of
river
terraces.—The
third
theory,
sug-
gested
in
explanation
of
terraces
in
Scotland
by
Hugh
Miller,
the
younger,
in
1882,*
recognizes
slow
regional
uplift
as
the
cause
of
valley
erosion
and
then
calls
attention
to
the
increase
in
the
number
of
resistant
obstacles—rock
ledges,
boulders,
till—that
the
degrading
river
will
encounter
as
it
swings
later-
ally
while
eroding
the
valley
floor
to
lower
and
lower
levels,
and
ascribes
the
decrease
of
interscarp
breadth
to
this
effectual
and
observable
cause.
As
Miller's
theory
has
not,
to
my
knowledge,
been
quoted
in
this
country,
except
in
a
brief
note
of
my
own,f
a
brief
exposi-
tion
of
its
merits
may
be
made.
I
have
found
it
very
generally
applicable
to
the
terraced
valleys
of
New
England,
and
nowhere
more
so
than
in
the
valley
of
the
Westfield
river,
between
the
eastern
base
of
the
Berkshire
hills
and
the
village
of
Westfield,
Mass.,
a
distance
of
about
five
miles,
where
I
have
repeatedly
examined
it.
This
district
was
the
scene
of
an
intercollegiate
excursion
in
the
autumn
of
1901,
in
which
Yale,
Amherst,
Williams,
Wesleyan,
Institute
of
Technology,
and
Harvard,
together
with
six
secondary
schools,
were
represented
by
teachers
and
students
to
the
number
of
forty-six
;
and
it
is
not
too
much
to
say
that
at
the
end
of
the
day's
walk
along
the
north
side
of
tlte
valley
no
doubt
remained
as
to
the
competence
of
Miller's
theory
to
explain
the
occurrence
and
the
pattern
of
the
terraces
there
seen.
Decrease
of
volume
and
intermittent
uplift
seemed
to
be
of
altogether
secondary
importance,
if
indeed
they
had
produced
any
recognizable
effect.
The
Westfield
terraces.
The
followino
,
pages
give
a
brief
account
of
the
Westfield
terraces,
beginning
with
those
on
the
*
River
terracing,
its
methods
and
their
results,
Proc.
Roy.
Phys.
Soc.
Edinb.,
1883,
263-305.
f
Bull.
Geol.
Soc.
Amer.,
xii,
1900,
483-484.
Davis—Terraces
of
the
Westfield
River,
'Vass.
79
north
side
of
the
valley
near
Westfield
railroad
station,
thence
going
west
about
two
miles
to
a
little
settlement
known
as
Pochassic
Street
;
and
returning
by
the
south
side
of
the
valley
to
the
village
again.
The
general
pattern
of
the
terraces
is
indicated
in
figure
6
(Plate
IV),
where
the
attempt
is
made
to
show
them
in
bird's-eye
view,
as
if
looking
northeast
from
a
height
of
two
or
three
thousand
feet
above
a
point
about
a
mile
south
of
Pochassic
Street.
The
scale
in
the
further
part
of
the
view
is
somewhat
smaller
than
in
the
foreground.
The
vertical
scale
is
significantly
exaggerated.
The
Boston
and
Albany
rail-
road
is
not
so
straight
as
it
is
here
drawn
through
the
valley
;
about
a
mile
and
a
half
of
its
length
is
shown.
Defending
ledges
are
drawn
in
black..
Roads
are
dotted.
3.
The
open
IVesVeld
plain.
Just
north
of
Westfield
station,
a
good
view
is
had
from
the
terrace
near
Prospect
hill
.schoolhouse,
A,
figure
6,
over
a
broad
plain
that
the
river
has
excavated
east
of
the
village.
The
plain
is
limited
on
the
north
by
a
single
high
terrace,
B,
rising
at
once
from
the
marshy
abandoned
river
channels
at
its
base
to
the
level
of
the
highest
drift
plain
of
the
district.
On
the
opposite
side
the
flood
plain
of
the
Westfield
is
confluent
with
that
of
(West-
field)
Little
river
(not
shown
in
fig.
6),
limited
on
the
south
by
a
single
high
terrace,
to-day
undercut
by
Little
river
at
two
places.
The
low
plain
thus
gains
the
unusual
breadth
of
a
mile
or
more
for
a
distance
of
about
two
miles
eastward
from
our
point
of
view.
The
two
rivers
here
show
no
incompetence
whatever
in
the
process
of
lateral
swinging.
Whatever
loss
of
volume
they
may
have
suffered—and
some
loss
since
the
disappearance
of
the
ice
sheet
is
highly
probable—and
how-
ever
recent
the
last
uplift
of
the
region
may
have
been,
these
two
streams
are
here
sweeping
over
a
broader
valley
floor
to-day
than
they
have
opened
at
any
earlier
time
;
for
whatever
earlier
flood
plains
they
have
formed
at
intermediate
levels,
during
the
process
of
excavating
their
valleys,
are
now
com-
pletely
undercut
and
destroyed
(except
for
a
few
low
terraces)
by
the
opening
of
the
present
broad
plain.
The
prime
reason
for
so
striking
an
exhibition
of
competence
on
the
part
of
the
streams
is
believed
to
be
the
absence
of
rock
ledges
in
this
section
of
the
valley.
No
ledges
have
here
been
discovered
by
the
degrading
streams
;
their
high
terrace
scarps
consist
of
clays,
sands
and
gravels
(the
latter
near
the
top),
very
easily
eroded
wherever
the
streams
flow
against
their
base,
as
may
be
seen
where
Little
river
is
now.
swinging
against
the
terrace
scarp
on
the
southern
side
of
the
plain.
A
secondary
reason
for
the
competence
of
the
river
to
swing
so
broadly
at
the
present
level
is
probably
to
be
found
in
the
delay
of
further
valley-deepening
and
in
the
resulting
detention
of
the
streams
80
Davis
Terraces
qf
the
Westfield
River,
.Bass.
close
to
their
present
grade
by
the
trap
sheen
which
their
united
current
has
come
upon
in
the
notch
in
the
trap
ridge
about
two
miles
east
of
Westfield.
4.
Terrace
diagrams.
The
single
high
terrace
scarp,
here
so
well
developed
and
typified
in
figure
1,
is
of
more
general
occurrence
in
the
terraced
valleys
of
New
England
than
is
generally
supposed
to
be
the
case.
It
may
indeed
be
taken
as
typical
of
many
terraced
valleys
where
no
ledges
have
been
discovered
to
prevent
the
free
swinging
of
the
rivers.
A
few
lower
terraces
may
still
be
unconsumed
here
and
there,
as
in
figure
2
;
this
arrangement
of
terraces
also
being
of
common
occurrence
where
ledges
are
wanting.
The
ordinary
diagram
of
a
terraced
valley,
such
as
is
here
reproduced
in
figure
3,
is
there-
fore
misleading
in
implying
that
the
stepping
terraces
have
been
carved
in
drift
alone,
without
relation
to
the
rock
beneath.
These
many-stepped
flights
of
terraces
need
for
their
preserva-
tion
a
number
of
ledges,
as
in
figure
4
;
but
this
figure
is
very
faulty
in
implying
that
ledges
occur
all
along
the
base
of
the
terrace
scarps.
As
a
matter
of
fact,
the
ledges
do
not
occupy
more
than
a
small
percentage
of
the
terrace
lengths,
and
far
from
all
lying
on
the
line
of
a
single
cross
section,
as
figure
4
implies,
they
are
frequently
distributed
somewhat
irregularly
lip
and
down
the
valley
sides.
The
true
relation
of
ledges
and
terraces
is
better
shown
in
a
block
diagram,
such
as
figure
5
;
and
even
here
the
area
of
the
ledges
exposed
in
the
terrace
cusps
is
exaggerated
over
that
commonly
observed.
5.
The
Westfield
spur
(Prospect
the
terrace
by
Westfield
station
is
now
crossed
to
the
west,
it
is
soon
found
to
be
a
spur
of
a
high,
but
not
of
the
highest
plain,
extending
forward
(southward
on
the
north
side
of
the
valley)
from
the
broad
plain
in
the
background.
It
is
known
as
Prospect
hill.
The
apex
of
the
spur,
E,
figure
6,
reaches
the
river
;
its
breadth,
east
and
west,
is
about
a
quarter
of
a
mile.
From
its
western
side
the
valley
floor
again
widens,
making
a
recess
or
re-entrant
in
the
high
plain
on
the
north
;
but
here
four
sub-
ordinate
terraces
are
found
beneath
a
stronger
scarp
that
rises
to
the
highest
level
;
they
combine
in
a
charming
landscape,
when
seen
from
the
western
scarp
of
Prospect
hill.
As
the
river
is
thus
found
to
have
been
competent
to
widen
its
valley
both
east
and
west
of
the
terrace
spur,
some
reason
for
the
pre-
servation
of
the
spur
should
be
looked
for
;
and
it
is
discovered
clearly
enough
on
descending
the
western
scarp,
which
is
found
to
be
defended
at
various
points
along
its
bank
by
sandstone
ledges,
C',
C",
C"'.
The
sandstones
are,
to
be
sure,
relatively
friable
;
they
are
weak
compared
to
the
schists
and
gneisses
of
the
Berkshire
hills
to
the
west
;
so
weak,
indeed,
that
while
the
Berkshires
retain
in
the
equable
height
of
their
uplands
a
Davis
Terraces
of
the
Westfield
River,
glass.
81
\\\
FIG.
1
FIG.
2
FIG.
3
FIG.
4
FIG.
5
82
Davis—Terraces
of
the
Westfield
River,
_Hass.
fair
indication
of
the
altitude
to
which
the
Cretaceous
peneplain
of
this
region
has
been
raised,
the
Triassic
sandstones
in
this
part
of
the
Westfield
valley
(part
of
the
greater
Connecticut
valley
lowland)
have
been
reduced
by
later
Tertiary
erosion
to
a
lowland
of
a
second
(or
n+1)
generation.
Yet
compared
to
the
silts
and
gravels
of
the
terraces,
the
sandstones
are
very
strong
whenever
the
river
has,
in
the
process
of
sweeping
the
drift
from
its
valley,
swung
against
a
sandstone
ledge,
pre-
viously
buried,
further
lateral
swinging
has
been
peremptorily
stopped
and
the
terrace
behind
the
ledge
has
been
preserved.
It
is
evidently
because
of
the
abundant
defending
ledges
here
that
the
Westfield
spur
has
not
been
destroyed.
The
stream
has
made
a
Most
determined
effort
to
destroy
the
spur
by
scouring
out
a
hollow,
C,
at
its
back,
sweeping
around
in
so
great
a
curve
that
its
normal
eastward
course
was
locally
turned
back
to
the
southwest
but
the
ledge,
C',
on
which
the
stream
was
caught,
could
not
be
removed;
and
hence
the
spur
still
stands
there.
The
river
seems
to
have
been
withdrawn
from
the
deep
recess,
C,
by
taking
a
short-cut
across
a
more
axial
part
of
the
valley
floor
of
that
time,
probably
during
a
flood.
When
it
again
swung
northward
towards
the
recess,
at
a
somewhat
lower
level
than
before,
a
lower
part,
D',
of
the
same
ledge
was
encountered
a
little
farther
forward
than
the
point,
C'
and
a
small
innate
area,
C,
of
the
earlier
sweep
was
therefore
preserved
back
of
the
new
terrace,
D.
On
the
third
return
of
the
river
into
the
same
locality
at
a
still
lower
level,
it
was
caught
by
a
small
ledge,
D",
several
hundred
feet
farther
forward,
and
again
by
larger
ledges,
C",
C'",
and
hence
a
good
stretch
of
the
flood
plain
between
D'
and
D"
was
preserved
in
a
terrace.
The
Westfield
river
is
at
present
making
still
another
effort
to
remove
the
spur,
and
it
is
now
for
at
least
the
fourth
time
stopped
by
a
member
of
this
group
of
ledges,
for
a
strong
reef
of
sandstone
is
seen
in
the
river
bank
at
E
in
the
southern
corner
of
the
spur.
The
spur
may
in
the
distant
future
be
somewhat
sharpened
by
losing
ground
on
its
undefended
south-
east
corner,
should
the
river
chance
to
swing
that
way
but
such
swinging
will
be
for
the
present
strongly
resisted
by
the
buttresses
of
two
bridges
and
by
artificial
embankment
where
the
Boston
and
Albany
railroad
follows
the
river
it
will
cost
less
to
restrain
the
river
than
to
remove
the
bridges
and
the
tracks.
6.
No
local
evidence
of
decrease
of
volume
in
the
Tirestfield
river.—Evidently
the
preservation
of
the
spur
of
Prospect
hill
is
not
due
to
any
incompetence
or
to
any
want
of
effort
on
the
part
of
the
river
to
remove
the
sands
and
gravels.
The
river
has
repeatedly
and
energetically
attacked
the
spur
it
has
in
Davis—Terraces
of
the
Westfield
River,
Mass.
83
the
most
competent
fashion
swept
away
all
the
drift
that
could
be
reached.
It
was
only
upon
encountering
the
stubborn
resistance
of
an
ambushed
and
impregnable
ledge
that
the
river
first
withdrew,
and
even
then
it
withdrew
only
to
renew
the
attack
by
returning
bravely
toward
the
spur
on
a
later
swing.
Unfortunately
for
the
reputation
of
the
river,
the
ambushed
ledges
have
been
found
entrenched
farther
and
farther
forward
at
every
successive
attack
that
has
been
made
upon
them
;
hence
the
river,
losing
ground
at
every
advance,
has
come
to
be
looked
upon
as
a
weakened
and
shrinking
stream
that
voluntarily
abandons
its
earlier
enterprises
and
accepts
a
narrower
limit
for
its
conquests
to-day
than
when
in
a
youth
of
(imagined)
greater
vigor
and
aggression
;
but
this
is
a
most
unjust
interpretation
of
its
behavior.
The
river
is
making
a
most
determined
and
heroic
effort
to
carry
out
its
original
plan
of
campaign.
It
is
eminently
successful
in
open-
ing
the
valley
east
of
Westfield,
and
if
it
is
defeated
at
the
spur,
this
is
only
because
of
the
reinforcement
of
the
uncon-
solidated
drift
by
the
invincible
strength
of
the
entrenched
ledges.
The
river
may
be
accused
of
want
of
foresight
in
not
more
carefully
reconnoitering
the
ground
that
it
originally
proposed
to
excavate,
but
it
is
notorious
that
rivers
are
heedless
of
buried
ledges,
on
which
they
often
become
inextricably
superposed.
The
river
may
be
thought
headstrong
to
return
to
an
attack,
a
forlorn
hope,
where
defeat
is
inevitable.
Heed-
less
and
headstrong
it
may
be,
but
it
does
not
deserve
the
reproach
of
being
looked
upon
as
enfeebled.
Even
if
its
volume
is
now
less
than
formerly,
the river
is
as
competent
to-day
as
it
ever
was
to
open
a
wide
flood
plain
in
drift,
and
it
does
so
wherever
free
opportunity
is
offered
of
carrying
out
its
original
enterprise.
7.
Relation
of
ledges,
terraces
owl
river
swings.—It
should
be
noted
that
the
ledges
of
the
Westfield
spur
have
not
in
any
case
determined
the
depth
to
which
the
river
has
cut
its
valley.
The
ledges
here
were
not
encountered
in
the
river
bed
but
in
the
river
bank,
and
hence
have
controlled
only
the
breadth
of
lateral
swinging
at
the
point
where
they
were
by
chance
dis-
covered.
The
depth
at
which
the
ledges
were
encountered
was
dependent
simply
on
the
amount
of
valley
excavation
that
had
been
accomplished
by
the
graded
river
at
the
time
that
the
discovery
was
made.
It
is
also
important
to
note
that
while
a
ledge
thus
encountered
in
the
bank
of
a
swinging
river
will
defend
and
preserve
that
part
of
any
flood
plain
previously
formed
at
a
higher
level,
above
and
back
of
the
ledge,
it
is
not
at
all
necessary
that
every
former
flood
plain
of
the
river
should
be
thus
recorded.
If
the
successive
northward
swings
of
an
east-flowing
river
have
by
chance
less
and
less
ampli-
84
Davis—Terraces
qf
the
[Test,*ld
River,
_Ilfass.
tude,
successive
terraces
will
remain,
even
without
defense
by
ledges.
There
can
be
no
question
that
some
of
our
terraces
are
of
this
accidental
kind.
But
the
undefended
lower
terraces
will
be
undercut
and
destroyed
if
the
river
swings
more
strongly
north
again.
If
the
river
again
swings
north
until
it
strikes
a
ledge,
the
uppermost
terrace
may
alone
be
preserved,
and
that
only
back
of
the
defending
ledge.
It
thus
becomes
evident
that
in
order
to
discover
the
number
of
times
that
a
river
has
swung
across
its
valley,
making
laterally
sloping
flood
plains
at
lower
and
lower
altitudes
at
every
swing,
we
must
not
trust
to
the
chance
preservation
of
flood
plain
remnants
in
terraces
here
and
there,
but
must
seek
a
flight
of
terraces,
systematically
grouped
on
a
long
sloping
ledge,
which
may
preserve
a
lateral
remnant
of
every
flood
plain
that
has
been
formed,
as
in
figure
5.
It
is
certainly
a
striking
fact
that
the
number
of
steps
in
a
flight
of
valley
terraces
always
reaches
a
maximum
in
just
such
situations.
The
preservation
of
numerous
terraces
of
moderate
height
on
long
sloping
ledges—however
few
such
ledges
there
may
be
in
the
valley
and
however
few
terraces
occur
elsewhere
on
the
valley
sides—goes
far
towards
excluding
the
theory
of
successive
uplifts
and
pauses
as
a
cause
of
terracing.
It
goes
far
also
towards
supporting
the
theory
that
the
wandering
river
has
been
swinging
from
side
to
side
across
its
valley,
always
degrading
its
channel
but
always
acting
as
a
graded
river,
during
the
whole
period
of
terracing,
whatever
may
have
been
the
cause
that
determined
the
excavation
of
the
valley
drift.
If
uplift
were
the
cause,
the
uplift
must
have
been
slow
and
relatively
uniform.
In
illustration
of
this
conclusion,
we
may
return
for
a
moment
to
the
broad
basin
east
of
Westfield.
No
terraces
at
intermedi-
ate
levels
are
found
here
to
prove
that
the
river
did
repeatedly
swing
laterally
while
degrading
its
valley
floor
in
this
part
of
its
course
;
yet
there
can
be
no
reasonable
doubt
that
the
river
really
did
swing
back
and
forth
here,
for
the
remnants
of
four
flood
plains
at
intermediate
altitudes
are
found
in
the
terraces
on
the
west
side
of
Prospect
hill,
only
half
a
mile
away.
Farther
up
the
valley
one
may
find
a
flight
of
nine
defended
terraces,
described
below,
whose
subequal
heights
range
from
ten
to
fifteen
feet
;
thus
proving
that
even
the
four
terraces
on
the
Westfield
spur
preserve
a
very
incomplete
record
of
the
river's
activity.
Evidently
the
maximum
number
of
steps
observed
in
any
terrace
flight
gives
only
the
minimum
number
of
swings
that
the
river
may
have
made
during
the
whole
period
of
degradation.
8.
Ledges
outcrop
on
the
up-valley
side
qf
terrace
spurs.—
In
the
terrace
spur
here
called
Prospect
hill,
as
in
many
others,
it
is
noteworthy
that
the
up-valley
side
of
the
defending
ledges
Davis—Terraces
of
the
Westfield
River,
_Mass.
85
has
been
clean
swept
by
a
swinging
curve
of
the
attacking
river.
This
may
be
explained
as
a
result
of
the
normal
progress
of
a
river
meander
down
the
valley,
until
it
is
stopped
by
coming
on
a
ledge,
or
abandoned
by
withdrawal
of
the
current
to
a
short-cut
or
cut-off
course.
The
fact
of
the
down-valley
progress
of
a
meander
does
not
seem
to
have
received
much
attention
from
physiographers,
judging
by
the
silence
of
text-
books
concerning
it
;
but
it
must
be
a
familiar•
matter
to
river
engineers,
so
conspicuously
is
it
exhibited
on
such
maps
as
those
prepared
by
the
Mississippi
River
Commission.
The
cause
of
the
down-valley
progress
is
evidently
to
be
found
in
the
con-
tinued
displacement
of
the
thread
of
fastest
current
to
the
down-valley
side
of
the
channel
on
entering
the
tangent
of
inflexion
between
two
meander
curves.
9.
Brown's
spur.--On
the
other
hand,
a
terrace
may
trail
some
distance
down-valley
from
its
defending
ledge,
unless
the
stream
should
by
any
chance
swing
in
again
and
sweep
it
away.
This
chance
has
not
happened
in
Prospect
hill,
the
spur
thus
far
considered
;
but
it
has
in
Brown's
spur,
F,
half
a
mile
farther
west.
This
spur
is
well
defended
by
a
large
sandstone
ledge,
at
whose
forward-reaching
base
the
river
is
now
flowing
in
a
vain
effort
to
widen
its
valley.
Four
terraces
in
the
next
up-valley
reentrant
curve
forward
to
the
apex
of
the
spur,
and
all
agree
in
the
most
unanimous
manner
to
sweep
tangent
to
the
slope
of
the
defending
ledge.
The
ledge
is
well
exposed
in
the
cuts
made
by
the
passing
road
and
railroad.
The
scarp
of
the
next
higher
terrace,
G,
is,
however,
pushed
back
a
quarter
of
a
mile
farther
north
;
evidently
because
when
it
was
made
the
river
was
swinging
at
a
slightly
higher
level
than
the
summit
of
the
defending
ledges
in
the
apex
of
Brown's
spur.
It
seems
undeniable,
when
one
looks
at
these
terraces
on
the
ground,
that
the
river
would
have
pushed
back
the
lower
members
of
the
series
about
as
far
as
the
higher
member,
if
its
lateral
swinging
had
not
been
stopped
by
the
ledge.
The
peculiar
feature
of
this
spur
is,
however,
the
close
trim-
ming
that
it
has
suffered
on
its
down-valley
side.
The
river
has
at
least
three
times
swung
northward
so
near
the
eastern
side
of
the
ledge
as
to
narrow
the
spur
into
a
sharp
point.
The
normal
down-valley
progress
of
the
meanders
cannot
be
appealed
to
as
a
cause
of
this
close
trimming
on
the
down-
valley
side
of
the
ledge
;
some
special
cause
must
be
looked
for
to
direct
the
several
northward
swings
of
the
river
over
so
nearly
the
same
course.
It
seems
probable
that
some
constraint
has
been
exerted
on
the
river
further
up
its
channel,
whereby
it
has
been
repeatedly
guided
to
the
down-valley
side
of
the
ledge.
A
possible
explanation
of
this
peculiar
feature
will
be
suggested
on
a
later
page.
86
Davis—Terraces
of
the
Westfield
River,
Mass.
10.
The
light
of
terraces
by
Pochassic
Street.--The
finest
flight
of
terraces
hereabouts
is
preserved
a
little
east
of
a
small
settlement,
known
as
Pochassic
Street,
on
the
southeastern
slope
of
Pochassic
hill,
a
drumlin,
around
whose
base
abundant
ledges
have
been
discovered.
The
settlement
and
drumlin
are
just
to
the
left
of
the
limit
of
figure
6.
The
highest
terrace,
H,
shows
waterworn
cobbles
and
pebbles
on
its
plain
;
the
bouldery
slope
of
Pochassic
hill
rises
behind
it.
Terraces
are
usually
counted
upward
from
the
valley
floor
in
the
reverse
order
from
that
of
their
production.
It
will
be
convenient
here
to
follow
the
natural
order
and
count
downward,
beginning
with
the
plain
and
scarp
of
the
highest
terrace
as
number
one.
Thickets
of
small
trees
and
bushes
obscure
many
details
here,
and
some
of
the
terrace
plains
are
inconveniently
swampy
near
their
back
border,
perhaps
because
of
ledges
farther
forward
by
which
the
ground
water
is
held
up.
Hence
the
correlation
of
some
of
the
terraces
in
this
locality
is
doubtful,
as
indicated
by
the
blanks
left
in
the
figure.
A
flight.
of
at
least
nine
steps,
H—M,
may,
however,
be
counted,
all
presenting
characteristic
concave
fronts
in
what
may
be
called
the
Pochassic
reentrant,
all
curving
forward
at
their
down-valley
ends
to
defending
ledges,
and
all
of
similar
height,
roughly
from
eight
to
fifteen
feet.
A
later
terrace
occasionally
undercuts
an
earlier
one,
so
that
the
two
scarps
are
locally
united
in
a
slope
of
more
than
the
average
height
;
such
being
the
case
with
the
fifth—sixth
scarp,
along
whose
base
lies
a
narrow
country
road
in
the
mid-
dle
of
the
reentrant
;
a
little
farther
east
and
west
the
scarp
is
divided
into
two
(or
more)
parts
by
a
narrow
terrace
that
comes
forward
at
an
intermediate
level;
thus
what
seem
to
be
the
fifth
and
sixth
swings
of
the
river
may
be
identified.
The
uppermost
terrace
may
be
followed
along
its
scarped
front
through
the
second
growth
of
bushes
and
trees
past
two
defended
cusps,
H
and
H',
beyond
which
it
turns
to
the
north-
east
and
at
a
distance
of
half
a
mile
or
so
seems
to
rim
tangent
to
another
drumlin.
The
second
terrace
is
not
identified
on
the
first
ledge,
II,
bat
appears
on
the
second,
H';
it
seems
to
fade
away
on
the
broad
plain
a
quarter
of
a
mile
to
the
north-
east.
The
third
terrace
is
caught
on
both
ledges,
II
and
H'
;
it
then
runs
eastward
half
a
mile
and
is
undercut
at
G
by
the
large
reentrant
between
Prospect
hill
(the
Westfield
spur)
and
Brown's
spur.
Shortly
before
it
is
cut
away,
a
low
terrace
turns
off
northeastward
from
it
and
seems
to
continue
some
distance
;
hence
what
has
just
been
called
the
third
scarp
might
be
taken
to
represent
the
fourth
northward
swing
of
the
river.
It
is
important
to
note
that
the
sharp
curvature
and
large
arc
of
the
reentrants
in
the
first
and
third
scarps
in
connection
with
the
ledges
at
and
H'
are
much
more
consistent
with
the
Davis—Terraces
of
the
Westfield
River,
.Mass.
87
behavior
of
a
river
similar
in
volume
to
that
of
the
present
Westfield
than
with
the
behavior
of
a
much
larger
river.
The
fourth
terrace
in
the
Pochassic
reentrant
is
caught
on
a
ledge
of
loose-textured
sandstone,
J,
that
stands
forward
from
the
first
small
reentrant
in
the
higher
terraces.
The
ledge
is
not
directly
exposed,
but
abundant
angular
fragments
of
pebbly
sandstone
are
found
in
the
apex
of
the
blunt
cusp
on
the
terrace
front.
This
terrace
is
believed
to
be
the
one
that
runs
forward
in
a
long
sweeping
curve
to
the
apex
of
Brown's
spur
;
but
it
has
not
been
followed
all
through
the
bushes
and
some
details
of
its
form
may
not
be
shown
in
the
figure.
The
divergence
between
the
eastward
course
of
the
third
and
fourth
terraces,
G
and
F,
is
highly
significant.
The
third
scarp
was
cut
a
quarter
of
a
mile
back
of
what
is
now
the
apex
of
Brown's
spur,
because
at
the
time
of
the
third
northward
swing
of
the
river,
its
channel
had
not
been
worn
deep
enough
to
catch
upon
the
summit
of
the
ledges
in
the
spur.
But
at
the
time
of
the
fourth
northward
swing
the
river
had
eroded
its
plain
to
a
lower
level,
so
that
it
was
held
by
the
topmost
ledge.
The
fourth
terrace,
therefore,
could
not
be
cut
so
far
back
as
the
third
;
it
makes
a
long
sweep
forward
from
the
Pochassic
reentrant
to
the
apex
of
Brown's
spur
and
leaves
a
rather
broad
plain
between
its
scarp
and
that
of
the
third
terrace.
It
is
per-
fectly-
evident
that
this
arrangement
of
the
two
terraces
was
not
clue
to
any
decreasing
strength
on
the
part
of
the
river,
but
to
the
constraint
imposed
upon
its
wandering
by
the
ledge
at
F.
11.
Perry's
spur.—Below
the
fourth
terrace,
J—F,
come
several
others,
which
run
forward
to
the
rounded
front
of
Perry's
spur,
K,
K',
where
several
blunt
cusps
are
determined
by
ledges
of
very
friable
sandstone
that
would
hardly
be
seen
but
for
cuts
made
by
the
road
and
the
railroad.
This
item
is
of
importance,
for
it
shows
that
certain
ledges
which
are
strong
enough
to
defend
a
terrace
are
not
always
bold
enough
to
keep
themselves
in
sight.
After
having
done
their
duty
in
fend-
ing
off
the
river,
they
strategically
weather
under
cover
and
thus
ambush
themselves
again
beneath
a
thin
sheet
of
their
own
waste
mixed
with
creeping
drift
from
the
terrace
they
have
protected.
It
is
possible
that
another
example
of
this
kind
may
be
found
in
the
well
defined
cusp,
D"',
of
a
low
terrace
in
the
reentrant
between
Prospect
hill
and
Brown's
spur
;
it
seems
at
first
to
be
only
the
free
intersection
of
two
curves,
for
there
is
no
sign
of
a
ledge
at
its
base
and
there
are
no
angular
fragments
of
sandstone
by
which
the
presence
of
an
ambushed
ledge
is
sometimes
revealed.
A
little
digging
or
a
boring
with
a
soil
auger
would
suffice
to
determine
this
point.
The
indefiniteness
of
some
of
the
terraces
in
the
Pochassic
reentrant
may
be
clue
to
the
discovery
there
of
till
underlying
88
Davis
Terraces
of
tie
Westfield
River,
11fass.
the
stratified
drift.
Till
is
seldom
well
carved
by
a
swinging
river
;
its
texture
is
significantly
firmer
than
that
of
stratified
sands
and
clays.
A
small
stream
coming
out
from
the
north
cuts
little
trenches
in
the
terrace
fronts
and
spreads
its
gravel
fans
on
their
plains,
thus
further
obscuring
their
forms.
The
eighth
and
ninth
members
of
the
.
Pochassic
flight
are
well
defined,
but
instead
of
conforming
to
the
concave
pattern
of
the
higher
members
of
the
series,
they
spring
forward
to
a
defended
cusp,
M,
nearly
opposite
the
middle
of
the
reentrant.
Here
as
elsewhere
it
is
perfectly
evident
that
the
failure
of
the
river
to
cut
back
these
lower
terraces
is
not
due
in
the
least
to
any
loss
of
its
original
strength,
but
to
the
increase
of
resistance
offered
by
the
ledges.
The
river
has
now
swung
away
from
the
northward
meander
that
it
followed
while
carving
the
lowest
terrace,
N',
to
a
correspondingly
strong
southward
meander,
T',
which
is
now
cutting
a
low
terrace,
T,
on
the
south
side
of
the
valley.
A
broad
flood
plain,
N,
has
thus
been
opened.
It
happens
curiously
enough
that
the
down-
valley
progress
of
this
southward
meander
has
just
now
brought
it
to
such
a
position
that
it
is
impinging
against
a
large
exposure
of
the
sandstones
at
AI.
The
normal
down-valley
advance
of
the
meander,
T',
will
soon
carry
it
past
the
ledge,
unless
the
caving
bank
at
T
is
protected.
For
the
present,
the
obstruction
caused
by
the
ledge
in
the
normal
flow
of
the
river
seems
to
have
produced
a
slight
bend
in
the
channel
a
little
farther
up-
stream.
When
the
meander
is
sufficiently
advanced
the
river
will
impinge
directly
on
the
unprotected
bank
between
111
and
L,
and
consume
it
rapidly,
leaving
a
sharp
cusp
at
M.
It
is
probably
in
some
such
way
that
the
sharpening
of
Brown's
spur,
referred
to
above,
has
been
accomplished.
There
has
already
been
some
undercutting
of
the
low
terrace
east
of
AI,
for
the
main
valley
road
was
swept
away
by
the
northward
swing
of
the
river
at
L
a
few
years
ago.
The
road
has
been
set
back
so
as
to
cross
Perry's
spur,
K',
north
of
the
railroad,
thus
causing
the
desertion
of
several
houses
on
the
low
plain,
R,
in
front
of
the
spur.
The
railroad
itself
is
threatened
by
the
river
near
L
;
the
caving
bank
has
been
worn
back
danger-
ously
near
the
track,
and
a
quantity
of
coarse
rock
blocks
has
been
thrown
in
there
to
stop
the
caving.
But
for
this
resist-
ance
the
river
would
probably
continue
to
swing
northward
until
it
encountered
a
low
member
of
the
group
of
ledges
in
the
southwest
base
of
Perry's
spur,
K'.
West
of
Pochassic
Street
another
large
reentrant
has
been
swept
out
on
the
north
side
of
its
valley
;
its
down-valley
side
is
well
defended
by
ledges
in
the
southwest
base
of
Pochassic
hill.
Davis
—Terraces
of
the
Westfield
River,
_Vass.
89
The
flight
of
nine
terraces
in
the
Pochassic
reentrant,
above
described,
constitutes
the
best
series
in
the
valley,
as
far
as
I
have
seen
it.
Closer
study
will
probably
increase
the
number
of
steps.
The
subequal
height
of
the
scarps
suggests
that
these
terraces
record
nearly
every
northward
swing
of
the
river
in
their
locality.
A
similar
number
of
swings
has
probably
occurred
elsewhere
the
record
of
them
is
incomplete
or
want-
ing
only
because
of
the
absence
of
defending
ledges.
It
may
therefore
be
concluded
in
general
that
it
is
only
in
localities
well
provided
with
ledges
that
one
may
expect
to
see
preserved
in
terraces
the
lateral
remnants
of
all
the
flood
plains
that
were
formed
by
the
swinging
river
during
the
excavation
of
its
valley
and
that
the
maximum
number
of
steps
in
a
terrace
flight
is
only
the
minimum
'limber
of
lateral
swings
made
by
the
river.
All
of
these
terraces
testify
to
the
graded
condition
of
the
degrading
river
at
the
time
the
terrace
plains
were
made.
The
nine
chance
samples
of
river
condition
thus
preserved
may
be
fairly
taken
to
show
that
the
degrading
river
was
meander-
ing
and
swinging
at
grade
during
the
whole
period
of
terracing
in
this
section
of
the
valley.
There
is
no
indication
that
the
individual
terraces
depend
in
any
way
whatever
on
individual
uplifts.
12.
Terraces
south
of
the
river.
The
terraces
on
the
south
side
of
the
valley
may
now
be
considered.
No
ledges
are
seen
on
this
side
of
the
river
within
the
two-mile
stretch
included
in
figure
(3.
The
first
ledges
are
found
half
a
mile
further
west
they
defend
the
eastern
or
down-valley
side
of
a
strong
reentrant
a
little
west
of
the
town
farm.
Correlated
with
the
prevailing
absence
of
ledges
is
the
absence
of
upper
terraces.
The
high
plain
is
habitually
bordered
by
a
strong
scalp
of
forty
or
more
feet,
beneath
which
there
may
be
several
low
terraces;
but
in
one
case
the
low
flood
plain
of
the
present
river
enters
a
strong
reentrant,
P,
to
the
base
of
single
scarp
by
which
the
whole
descent
is
made
from
the
high
plain.
Nowhere
in
this
district
is
there
a
flight
of
low-scarped
terraces
from
the
top
to
the
bottom
level
on
the
southern
side
of
the
valley.
The
reason
for
this
contrast
between
the
two
sides
of
the
valley
may
be
with
confidence
ascribed
to
the
general
south-
ward
shifting
of
the
belt
within
which
the
river
swings,
because
of
the
southward
slope
of
the
ledges
on
the
north
side
of
the
valley
and
the
undefended
condition
of
the
terrace
drift
on
the
south
side
of
the
valley.
It
is
a
sort
of
monoclinal
shifting
of
a
river
course.
The
several
low
terraces
on
the
south
might
seem
at
first
to
contradict
this
explanation.
They
may,
how-
ever,
be
reasonably
explained
as
being
not
yet
swept
away.
The
river
cannot
attack
the
whole
length
of
the
southern
side
of
the
valley
at
once
it
will
swing
against
the
southern
90
Davis—Terraces
of
the
Westfield
River,
.3fass.
terraces
only
here
and
there,
now
and
then
and
hence
the
destruction
of
the
lower
southern
terraces
by
the
southward
shifting
of
the
belt
of
river-swinging
can
only
be
accomplished
progressively.
Thus
viewed,
it
is
no
wonder
that
some
of
the
lower
southern
terraces
still
remain.
This
corollary
to
the
explanation
above
suggested
receives
much
support
when
examination
is
made
of
the
relation
between
the
defended
cusps
of
the
terraces
on
the
north
and
the
concave
reentrants
of
the
terraces
on
the
south,
to
which
we
now
proceed.
13.
Correlation
of
terraces
on
the
two
sides
of
the
valley.—
It
will
be
readily
understood
that,
wherever
a
terrace
scarp
curves
forward
from
a
concave
reentrant
to
a
defended
cusp,
the
river
must
have
once
flowed
along
the
base
of
the
scarp
and
must
have
continued
the
line
of
the
terrace
curve
past
the
cusp
toward
the
opposite
side
of
the
valley,
there
to
recurve
toward
the
general
valley
axis.
The
farther
forward
the
defended
cusp
reaches
toward
the
axis
of
the
valley,
the
more
likely
it
is
to
direct
the
departing
river
strongly
against
the
terraces
on
the
opposite
side
of
the
valley.
Thus
the
curved
scarps,
K',
K",
K"',
of
the
northern
terraces,
suggest
that
the
river
has
formerly
flowed
on
past
the
defending
ledges
of
Perry's
spur
at
these
several
levels
and
has
thus
entered
the
reversed
curves
of
the
southern
scarps,
S',
S",
S"'.
The
levels
of
the
terraces
concerned
seem
to
correspond
by
pairs,
but
they
have
not
yet
been
accurately
measured.
Of
the
three
northern
scarps,
the
one
leading
to
K'
has
the
strongest
curvature,
for
the
middle
of
its
reentrant
is
cut
farther
back
than
the
middle
of
the
others.
When
the
river
flowed
at
the
base
of
this
scarp,
its
current
must
have
departed
from
the
defending
ledge
almost
transversely
to
the
general
eastward
course
of
the
valley.
Con-
sequently
the
corresponding
southern
scarp,
S',
makes
a
strong
reentrant
on
the
south
side
of
the
valley.
The
second
scarp,
K",
of
the
northern
group
was
more
gently
curved
the
third
scalp,
K'",
still
more
gently
curved
and
the
same
relation
is
seen
in
S"
and
S'".
It
is
possible
that
even
the
higher
southern
reentrant,
S,
is
indirectly
related
to
the
ledges
of
the
northern
valley-side
about
K
the
general
curvature
of
the
river
being
determined
by
the
ledges
and
a
southward
swing
of
the
curving
river
there
causing
the
excavation
of
the
reentrant,
S.
It
is
proposed
to
make
a
careful
measurement
of
all
these
terraces
in
order
to
test
their
correspondences.
Another
example
of
this
cross-valley
relation
is
found
far-
ther
west.
The
curved
scarp
of
the
lowest
northern
terrace,
N',
that
sweeps
out
to
the
defending
ledges
at
M,
is
the
north-
ern
member
of
a
double
curve
whose
southern
member
made
the
strong
concave
sweep,
P,
already
mentioned,
under
the
high
southern
terrace
plain.
The
ledges
at
M
stand
unusually
Davis—Terraces
of
the
Tirest,fleld
River,
3fass.
91
far
forward
toward
the
valley
axis
;
this
southern
sweep
is
therefore
the
only
one
that
has
consumed
all
the
southern
ter-
races
at
intermediate
and
low
levels.
The
abandoned
channel
of
the
sweep
is
still
swampy
and
the
enclosing
scarp
is
still
uneven
with
landslides,
so
lately
has
the
river
been
withdrawn.
It
is
natural
enough
that
the
river
should
not
have
swung
so
far
south
at
higher
levels,
for
the
guiding
ledge,
M,
is
rather
low
;
it
was
not
encountered
until
the
river
had
cut
down
its
flood
plain
nearly
to
the
present
level.
Inasmuch
as
the
southern
sweeps,
S'
and
P,
seem
to
have
been
guided
by
the
northern
ledges,
K'
and
M,
it
is
natural
to
find
the
unconsumed
remnant
of
the
terrace
between
the
two
sweeps
in
the
form
of
a
cusp,
Q.
This
cusp
is
about
forty-five
feet
high.
It
is
entirely
undefended
and
might,
therefore,
at
first
sight
be
classed
with
free
cusps,
and
re-
garded
as
the
consequence
of
a
chance
intersection
of
succes-
sive
meander
sweeps
on
the
valley
side.
But
the
dependence
of
the
sweeps,
P
and
S',
upon
the
defended
spurs
on
the
northern
side
of
the
valley
shows
that
the
strong
southern
cusp,
Q,
is
not
altogether
accidental.
It
is
in
reality
a
natural,
although
an
indirect
and
temporary,
product
of
the
northern
ledges
at
M
and
K'.
Unlike
the
defended
northern
spurs,
which
are
relatively
permanent
features,
the
indirectly
de-
fended
cusp,
Q,
will
not
endure.
Its
apex
is
already
trun-
cated
by
a
chance
swing
of
the
river
against
it
;
it
will
be
more
and
more
consumed
as
such
swings
are
continued
and
repeated.
It
is
safe
only
so
long
as
the
river
flows
on
curves
determined
by
the
ledges
at
M.
and
K'.
The
truncated
free
cusp,
W,
on
the
south
side
of
the
valley,
is
probably
related
to
Brown's
spur,
F,
in
much
the
same
way
that
the
truncated
spur,
Q,
is
related
to
Perry's
spur,
K'.
Another
southern
cusp,
T,
is
the
remnant
of
a
15-foot
ter-
race
projecting
far
into
the
valley
between
the
southern
re-
entrants,
T'
and
P.
A
strong
scarp,
T",
with
blunt
salients
rises
to
the
high
plain
back
of
T.
The
sharp
apex
of
the
cusp
points
directly
to
the
ledges
at
M,
yet
it
is
entirely
unde-
fended
south
of
the
river.
It
is
probable
that
there
was
something
of
up-valley
carving
on
the
eastern side
of
the
cusp
;
a
relatively
unusual
process,
for,
as
has
been
stated
above,
river
meanders
normally
progress
down-valley.
But
in
this
case,
the
down-valley
progress
of
a
northern
meander
was
stopped
by
the
ledge
at
M.
The
ledge
probably
acted
as
a
sort
of
fulcrum
as
soon
as
the
river
impinged
upon
it
;
the
deeper
the
northern
reentrant,
N',
was
cut,
the
more
nearly
the
river
must
have
turned
square
across
the
valley
at
M,
and
the
more
it
must
have
been
turned
against
the
down-valley
side
of
the
spur,
T.
Something
of
the
same
kind
probably
occurred
when
the
reentrants,
5
1
',
5",
S"',
were
scoured
out.
92
Davis
Terraces
of
the
Irestlield
River,
_Mass.
14.
Development
of
future
meanders.—The
river
is
evi-
dently
tending
to
become
more
curved
at
its
northward
bend,
L,
and
its
southward
bend,
Q.
It
was
formerly
less
curved
;
and
it
was
probably
then
that
it
ran
into
the
strongly
concave
reentrant,
V'.
No
immediately
local
cause
is
found
for
the
preservation
of
the
low
spur,
V,
for
no
defending
ledge
is
to
be
seen
at
its
apex
;
but
one
may
be
there,
buried
in
the
flood
plain
deposits
;
the
sandstone
outcrops
in
the
little
island
near
by
and
in
the
cusp
F
nearly
opposite.
It
is
possible
that
these
ledges
held
the
river
in
the
channel
between
them
(on
the
north
side
of
the
present
island)
while
the
river
scoured
out
the
sharply
concave
reentrant,
V'
;
and
that,
as
the
river
in-
creased
its
curvature
at
L
and
Q,
it
withdrew
from
the
curve
of
V'.
Such
a
series
of
changes
would
not
be
inconsistent
with
what
is
known
of
the
development
of
river
meanders.
Their
greatest
dimensions
are
attained
only
where
the
curves
are
well
organized,
and
such
organization
requires
time
for
its
accomplishment.
A
limit
is
set
to
the
size
of
the
carves,
less
by
an
equilibrium
between
current
and
bank
than
by
the
abandonment
of
the
curves
when
short
cuts
and
cut-offs
are
made.
The
river
course
is
thereby
made
nearly
straight
again,
after
which
a
new
series
of
curves
is
gradually
estab-
lished.
The
Westfield
river
hereabouts
is
comparatively
straight
to-day.
Its
course
for
several
miles
eastward
from
T
must
be
much
less
curved
now
than
when
the
concave
terrace
fronts
were
carved
at
various
earlier
dates.
But
a
.strong
curve
is
seen
to-day
at
T';
the
curves
at
L
and
Q
are
increas-
fng
and
their
maximum
curvature
is
not
yet
reached,
and
hence
it
may
be
expected
that
another
period
of
organized
meandering
is
approaching.
The
restraint
of
the
ledges
at
M
will
soon
he
avoided
by
the
down-valley
progress
of
the
mean-
der
T.
The
northward
curving
at
L
will
be
resisted
by
the
railroad.
The
southward
curving
at
Q
may
be
delayed
by
the
abundant
fall
of
gravels
from
the
truncated
end
of
the
spur
;
and
indeed
there
are
already
some
indications
that
the
river
may
bend
southward
into
the
low
flood
plain
west
of
the
spur.
A
stronger
northward
turn
toward
F
would
thus
be
induced
and
a
stronger
southward
turn
might
then
follow
farther
east-
ward.
The
latter
item
in
this
series
of
changes
would
be
made
more
probable
if
the
swinging
river
would
again
pass
the
ledges
at
F
on
a
southeastward
course,
as
it
did
when
carving
the
up-valley
side
of
Brown's
spur.
All
these
details
are
relatively
trifling,
yet
they
have
a
value
in
that
they
unite
in
showing
the
competence
of
ordinary
pro-
cesses,
appropriate
to
a
meandering,
swinging
and
slowly
de-
grading
river,
to
produce
even
the
most
minute
forms
of
our
terraces.
There
is
no
demand
for
an
ancient
river
of
great
Davis
Terraces
of
the
Westfield
River,
Mass.
93
volume
or
for
repeated
movements
of
uplift
in
the
terrace
problem
of
the
Westfield
river.
15.
Southern
terraces
at
WesVeld.
Nearer
Westfield
the
complication
of
the
southern
terraces
increases
somewhat,
and
there
is
one
member
of
the
series
at
a
higher
level
than
elsewhere
on
the
south
side
of
the
valley
in
this
district.
It
may
be
therefore
inferred
that
the
river
belt
has
hereabouts
been
shifting
northward,
and
this
would
be
confirmed
by
the
high
terrace
of
the
opposite
northern
reentrant.
Yet
no
ledges
are
found
on
the
south
side
of
the
valley
as
a
cause
of
this
shifting.
The
only
explanation
that
I
have
thought
of
for
it
is
that
Little
river
once
entered
the
Westfield
from
the
south
near
the
present
site
of
Westfield
village,
and
thus
slowly
pushed
the
Westfield
river
northward
from
the
course
it
had
previously
followed.
Interference
of
one
river
with
another
in
this
way
has
been
suspected
in
the
eastern
basin,
beyond
Westfield,
and
in
several
other
localities
in
the
Connec-
ticut
valley.
16.
Conclusions.
The
most
manifest
conclusion
to
be
drawn
from
this
study
is
the
one
already
announced
;
namely,
that
Miller's
theory
of
defending
ledges
gives
a
better
explanation
than
any
other
for
the
terraces
of
our
New
England
valleys.
It
is
not
desired
to
imply
by
this
that
all
our
terraces
are
de-
fended,
but
that
most
of
them
are
;
and
especially
that
all
the
many-stepped
flights
of
terraces
owe
their
preservation
to
defending
ledges.
Decrease
of
river
volmne
and
intermittent
uplifts
do
not
seem
to
have
had
any
significant
part
to
play
in
the
restriction
of
the
swinging
rivers
to
narrower
and
nar-
rower
belts.
Another
conclusion
is
that
the
normal
action
of
a
meandering
and
swinging
river
suffices
to
account
for
prac-
tically
all
the
details
of
terrace
form
;
and
hence
that
terraces,
like
other
land
forms,
are
susceptible
of
explanation,
even
down
to
their
most
minute
elements.
Following
this
there
is
a
third
conclusion,
of
interest
to
those
who
concern
themselves
especially
with
the
study
of
land
forms
;
namely,
that
in
this
division
of
the
subject
as
well
as
elsewhere,
observation
is
greatly
aided
by
the
discovery
of
a
successful
theory
for
the
essential
facts
are
then
quickly
acquired
by
well
directed
search.
It
is
also
apparent
that
here
as
elsewhere
description
is
greatly
facilitated
by
explanation,
for
explanation
enables
the
student
to
bring
the
local
example
into
proper
relation
to
the
generalized
type.
Thieve
may
seldom
be
necessity
of
giving
minute
description
of
forms
so
small
and
so
ephemeral
as
drift
terraces
;
but
when.
that
necessity
arises
it
will
be
met
better
by
characterizing
terraces
in
terms
explanatory
of
their
origin
than
by
an
attempt
at
absolute
or
empirical
description
;
AM.
JOUR.
SQL-FOURTH
SERIES,
VOL.
XIV,
NO.
80
-AUGUST,
1902.
7
94
Davis—Terraces
of
the
Westfield
River,
_Mass.
the
defended
and
the
free
cusps,
the
high
scarps
without
out-
cropping
ledges,
the
flights
of
advancing
terrace
steps
in
asso-
ciation
with
groups
of
outcropping
ledges,
the
correlations
of
the
terraces
on
the
opposite
sides
of
a
valley,
all
these
items
are
best
told
by
explaining
them.
Finally
it
may
be
noted
that
even
the
geologist
who
is
con-
cerned
only
with
the
underlying
rocks
may
well
afford to
give
some
heed
to
the
pattern
of
drift
terraces;
for
he
will
be
most
quickly
guided
to
his
desired
outcrops
if
lie
examines
the
points
and
the
up-valley
sides
of
the
terrace
cusps.
Cambridge,
Mass.,
June,
1902.
looking
northeast.
D
C
D'
C
l"
Am.
Jour.
Sci.,
Vol.
XIV,
1902.
Plate
IV.
FIGURE
b.
Sketch
of
the
Terraces
of
Westfield
river,
in
bird's
eye
perspective,
.......
.••
D"
WEST-
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-
5
BOSTON
WORCESTER,
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