The geology of Connecticut
and Rhode Island
is absolutely fascinating.
And it's kind of a
key to understanding
the geology of the northern
Appalachian Mountains
as a whole for this reason that
the Appalachian Mountains have
quite a lot of
diversity within them.
And they can be divided best
in southern New England,
where it's quite
clear what the eastern
and the western
mountains are like
and how they differ,
one from the other.
And then there's the
Connecticut Valley,
which is a lowland region
with a lot of volcanic rocks
that is in between.
So three divisions
are quite strong.
And there are other
subdivisions besides that.
Geologic history goes back to
approximately 600 million years
in eastern Rhode
Island and Connecticut,
so that that's the earliest
historical event recorded
in the rocks.
Whereas, in western
Connecticut, the early history
starts about 2.1, 2.2
billion years ago.
And so western Connecticut
has rock formations
that are part of the mainland
continent of North America.
Whereas, the eastern part
of southern New England
is made up of, you might say,
the off-shore or the part
of eastern North
America that was
located in Africa at the time.
So there's quite a diversity
in each of these places.
For instance, if
you're talking about
or interested in the
early history of mining
in southern New
England, and therefore,
the early history of how the
colonists got along once they
arrived here without any tools--
they would naturally
have to look
to the natural resource of the
countryside, wouldn't they?
And so that was the case, not
only with eastern New England,
but also of western New
England, and in particular,
western Connecticut
and eastern New York,
as well, and western
Massachusetts, in addition.
The plate tectonic history of
southern New England and New
England, in general, is
a most fascinating story.
The Earth is made up of
plates of rock, you might say,
that have several
different components.
And each of these are dated
back to certain periods of time.
For instance, in the
Berkshires of Connecticut
and Massachusetts, the old
rocks in the Berkshires--
and they call the whole
thing the Berkshires--
that's a very mountainous
area with older rocks
that we refer to as
gneisses and schists.
These are old rocks
that have been really
through the geological
mill, so to speak.
And they have been changed, in
terms of the minerals that they
consist of, as a result
of changes in temperature
and pressure over time.
And so that those old rocks are
the ones where you would find--
more commonly than
other places--
deposits of such metals
as iron and other metals
that could be used for
commercial purposes.
When the settlers first came
to eastern Massachusetts,
for instance, they
found bogs and bog iron.
They found that
the bogs had scum
on them that contained iron.
And so they had
ways of processing
that iron-bearing scum.
And they called it bog iron.
So it consisted both
of sediment of pieces
of rock formation,
and also of mud,
and iron that was washed
in there and deposited.
And so, that
particular ore, they
recognized that
it had iron in it
and that this could be
worked on metallurgically
in a primitive
sense, you might say.
And it could be smelted.
They could fire
it up and melt it,
melt the contents,
especially the metal,
and then pound out
the impurities,
and make a pretty good
quality iron ore out of it.
They could make plows, shovels,
rakes, cannonballs, and cannons
themselves, and just
anything that you
can think of that you might
need if you came into a new land
and were looking to make
a living for yourself
and your family.
In the Berkshires of
western New England
and in eastern New York,
there are deposits of iron.
And nearby, you
find these smelters.
These are chimney-like
features that--
I have photographs in my
book on the roadside geology
of Connecticut and Rhode Island.
But especially, there are
31 forages and foundries
where the ore was smelted,
made into partially liquid.
And then the impurities
and gotten out of it.
And so they had a
whole processing plant
that was developed as a
result of the material
that they found there.
In the Connecticut Valley
south of Hartford--
they call that whole valley
from Greenfield, Massachusetts
all the way down to Long Island
Sound to be the Connecticut
River Valley.
And the rock formations
in that valley,
which goes from about, oh,
from practically just a few
hundred yards across up at north
end north of Greenville to 15
or 20 miles broad as you get
in the vicinity of New Haven.
And there, you have
the rock formations
that crop out at the
surface are red rocks.
So they're a very
pretty kind of rock,
especially in the sunset
and the shades of color.
Whereas, many of the
other rocks that we
find in other parts of
southern New England
are very interesting.
And I think, to a geologist,
they're quite pretty.
But they're not the kind of
scenery that you might find
in Arizona highways-- you know,
the pictures that you find
there--
or in National Geographic.
Around Meriden in Connecticut--
that whole area is
referred to as the Hanging
Hills of Meriden.
And Meriden is located
south of Hartford.
It begins probably 15 or
20 miles south of Hartford.
And as you go south, the hills
rise up higher and higher
in the middle of this valley.
So what is further north--
a fairly flat valley except
for a few smaller ridges--
becomes some high cliffs.
And around Meriden, you
have these volcanic rocks.
And you probably have seen
pictures of the Palisades
along the Hudson River.
And these palisades are
named for the feature
that the early
colonists described
where you have a
compound to keep
the animals and
any predators out,
and to keep the colonists
in and protected.
And they set these
polls in the ground.
And they make it their kind of
logs that, often enough, are
pointed in an upward direction
to impale any animals
or predators that might try
to get into the compound.
So they call those palisades.
But in the Palisades
of the Hudson River,
which is beyond the
area of this book.
But we have palisades in eastern
part of the Connecticut Valley
northeast of New Haven and
in western Connecticut Valley
north of New Haven itself.
And as you travel
through that countryside,
you come to these
big walls of lava
that rise up out of the ground.
And they are, generally,
reddish rocks--
reddish to brown-- and they form
pillars or palisade-like shaped
in some respect like logs--
six-sided blocks
of rock, typically.
And those are called palisades.
And so these columns
are fit close together.
And that's a
function of the fact
that the lava, when it
cooled, cools into--
it in the ideal fashion--
into six-sided columns,
hexagonal columns.
And so these great sheets
of lava, great flows of lava
have come out of these volcanoes
in the Connecticut Valley
and have filled large
parts of the Valley.
And when these lava flows that
are some 500 feet thick, when
they cool, they cool into
a hexagonal, columnar form.
And that is quite spectacular.
New England, in general--
in the Appalachians, I think
you might say, in general--
contain a lot of
hard stone in part,
but is very beautiful,
particularly when polished,
and very often, when you just
take it out of the ground
as it is, and fashion it
into maybe different shapes.
And so there's quite a variety
of different kinds of rock
that are found in the
Appalachian Mountains.
And we're talking here about
the Appalachian Mountains,
of course.
On this particular
Boston College campus,
we have the eagle in
front of Gasson Hall.
And it sits on a
pillar of granite
from Branford, Connecticut.
And the history of
that pillar, why
it happens to be in front of
Gasson Hall, is that it was,
at one stage--
probably around, well,
maybe 1950 or '55,
some of the base of the
Admiral Dewey statue
was positioned on the
top of this pillar down
in front of South Station.
And so when the Southern
Artery was constructed
through the area just in
front of South Station,
they had to do something with
Admiral Dewey and his pillar.
And so Boston College became
the recipient of that pillar.
And so this
beautiful, red granite
from Branford,
Connecticut called
the Stony Creek granite was
set up in front of Gasson Hall.
The central part of
Connecticut and New England,
it seems like an odd thing
to have very high mountains
in the central part
of the mountain belt,
as opposed to having them
all in western Connecticut.
And so some of
these old rocks that
were in the range of
400 to 500 million years
old in the Bronson Hill
area are of interest.
The Bronson Hill
domes are a series
of domical structures,
up-arched domes that
form a big ridge all the
way from northwestern Maine
through New Hampshire,
and eastern Vermont
through Massachusetts,
and into Connecticut,
down to the Long Island Sound.
And what is particularly
interesting to me about--
we call it the
Bronson Hill domes.
And the Bronson Hill domes have
been characterized, many years
ago, as a series of volcanoes.
And indeed, they have had
volcanic activity in abundance
in those rocks.
But that's not the only
thing that's happened there.
They have been the
site of persistent
volcanic and plutonic activity.
That is to say, the
plutonic activity
is the eruption of
molten rock that
becomes heated, and becomes
explosive, and becomes volcanic
not only in volcanic
fragments, but also
in the lava that is poured
out from the volcanoes there.
So these mountains that
are very near Hartford--
just if you go across the
Connecticut River at Hartford
into east Hartford,
you then quickly
get into a couple
of townships nearby
that start becoming
quite mountainous.
And so those
particular mountains
are kind of a strange
phenomenon to be found right
in the middle of this complex
of eastern Connecticut
and western.
The rock formations in these
mountains in southern New
England, some of them have
moved toward the west.
And some have moved
toward the east.
Now when I speak of
them moving, what I mean
is that, over the course
of millions of years,
there have been
forces at work that
have pushed the large
tracts of terrain, including
the mountains themselves,
in westward directions
in the western part
of New England,
and in an eastward
direction once you
get east of the Connecticut
River into Manchester,
and some of the
areas near Manchester
on the east side of
the Connecticut River.
So when the geologists
talk about tectonics,
they're talking about the
movement of these plates.
And so if you ask, what are
the tectonic forces that
are making these gigantic
blocks of rock that
are almost of continental
proportions move as blocks
from time to time and over great
distances over long periods
of time?
And the answer is that
these blocks of rock
are moving blocks of the
upper portion of the Earth.
So what I'm saying
is here, if you
go to the latitude of New
Haven and southern Connecticut,
you'll find that the Connecticut
Valley with its volcanic rocks
is approximately, oh,
20 to 30 miles across.
Whereas, up in Greenfield, the
breadth of the volcanic valley
is probably a mile or 2 miles.
And then it thins down
so that it's just a line
once you get into New
Hampshire and Vermont.
And how can that be?
And so as you look
at these rocks
and map them out
carefully, you'll
find that there is evidence
that, east of the Connecticut
River area, east of the
Connecticut Valley that
is a volcanic valley, the
rock formations have been
progressively moving eastward.
And west of the
Connecticut Valley,
they've been moving
progressively westward.
And most people don't think
of the terrain as moving.
And when we speak about tectonic
movements, that's what we mean,
that the mountains
are in process
of moving periodically--
maybe only
the breadth of a hair per year
to year, or maybe a millimeter
every year or two.
But add up all those
years in millimeters,
and you can cover quite
a bit of distance.
And that's how these
continents have moved.
So just trying to understand
the vast movements
that the crust of our
Earth has been through
is really fascinating stuff.
There is a vast bibliography
of written resources
on the geology of
the Appalachian
Mountains and elsewhere, in
both books and in journals.
And so these are
very important to me,
in terms of preparing The
Roadside Geology of Connecticut
and Rhode Island that I have
here that's just come off
the press about, oh, a
month ago and then also
The Roadside Geology of
Massachusetts that came out
in 2001.
And so in the back
of these books
are, oh, I think,
all told, probably
a couple of hundred or
more outstanding resources
from the literature
on geology that I used
and which are very valuable--
and anybody in the
purview of anybody
that wants to learn
more in detail than what
is contained in the books.
We can only kind of skim
the surface of the geology,
so to speak, in thin books
like these 300-page books
that I've written,
but there's so much
wonderful information
available to describe
these beautiful rocks.
Be sure that you are
aware that you're on roads
that can be highly trafficked.
And keep off the tarmac.
Because it can be quite
dangerous and can be hazardous.
Because your curiosity
factor along the highway.
And you will find
that, if you're
looking at some of the
outcrops along the highway,
that you'll see people
honking their horn at you just
for the fun of it, and
others, because they
think you might be a hazard.
One good step is to go to
some of the local museums.
Or there are mineral collectors
everywhere around New England.
And I think this
is especially true
because there were mineral
clubs that found Connecticut
to be a really marvelous
gem in itself for collecting
these various
stones, and minerals,
and including
precious gemstones.
So Western Connecticut has a
lot of these mineral deposits.
And so I think if you had
an interest in going out
in the field and
collecting minerals,
the best thing you could do
is to join a mineral club.
And they have a regular
organized field trips
to various parts of southern
New England, for the most part,
and then also, to
other parts, too.
And they have little
guidebooks that
are prepared by the
local mineral hunters,
and describing what
kind of minerals
you'd find at a
particular locality,
and how to get to that locality.
