How Has The Geology Of Vermont Affected Its Character?

Sep 8, 2017

If you’ve lived in a state for a long time, or grew up there, you probably have this feeling — when you drive into or out of it, you feel like you can tell the difference.

For many people, this is very true for crossings in and out of Vermont. There’s a different look; there’s a different feel. For people who aren’t from here, there’s a different perception of what Vermonters are like, what they value.

Most of this is completely subjective, and probably best attributed to the oft-cited "myth of Vermont exceptionalism." But when we’re talking about a very specific local comparison — Vermont versus New Hampshire? Well, it turns out there is a very strong foundation for it. It’s made out of bedrock.

“The difference between Vermont and New Hampshire geologically is really based on the history of how they formed,” says Steve Trombulak, a professor of environmental studies at Middlebury College. “It's a complex story that goes back over a billion years.”

This month on Brave Little State, VPR’s people-powered journalism podcast, geology and identity.

The question driving our inquiry comes from Matt “Beagle” Bourgault:

"What does the geology have to do with the character of Vermont? How do the underlying, rocks, soils, topography affect how Vermont is different from other New England states and from New York?" — Beagle Bourgault, Hinesburg

And because it’s kind of a thing to compare the Green Mountain State to the Granite State — maybe you could say we have a friendly rivalry — we’re going to focus on this particular cross-border difference. And we’re going to pick up the story a few hundred million years ago, in the Paleozoic Era. 

Beagle lives in Hinesburg. He went to Colby College in Maine, and when he was there he took a few classes in geology.

“It was just something I was really interested in,” he says. “So I just feel like I keep asking those questions. Anywhere I go, it’s kind of like, 'Oh, why are the rocks like this?'”

And that's what got him thinking about Vermont’s rocks, and how they might have shaped the kind of place Vermont is — and made it so different from our neighbors.

Beagle Bourgault, of Hinesburg, has been wondering how Vermont's underlying rocks have shaped what kind of place it is, and made it different from its neighbors.
Credit Courtesy

“You know, driving from Vermont to New Hampshire, you cross the state line, it looks different. It just seems like, ‘Oh, now we’re in New Hampshire.’ Like you can kind of tell. It’s funny.”

And because Beagle has that background in geology, here’s where his head goes:

“It’s kind of like … Well it looks different, why would it look different? Oh, there are more oak trees. Why would that be the case? Maybe because the soil’s different. Oh yeah, well the soil is certainly more sandy, and if that’s the case, then it’s more acidic soil, so then, well, how does that affect the plants, which means agriculture? And if agriculture’s different, how does that affect how people have used the land, natural resources, all of that? So for me, it’s kind of like, it all just keeps coming back to, what’s underlying everything is the geology of it.”

Beagle is on the right track here. Because the geology of a place does affect what it’s like above ground. And in the case of these two states, Vermont and New Hampshire, spooning across the Connecticut River, there are some geologic differences that give rise to other differences.

But before we get too far into this, let’s make a quick note: There’s not a clear dividing line in the geologic or cultural differences between Vermont and New Hampshire. We’re going to be talking about bedrock and soil and also how those things shaped the states’ economies — but there will always be local variations and exceptions. States aren’t monolithic.

Brave Little State is VPR's people-powered journalism podcast.
Credit Aaron Shrewsbury

Deep history

But there is something to the idea that the differences between the Granite State and the Green Mountain State go all the way down to the rock below us.

“Vermont was formed at a different time. The land base, the rock base of Vermont was formed at a different time than was New Hampshire,” says Middlebury College’s Steve Trombulak, the co-author of the book The Story of Vermont: A Natural and Cultural History.

To understand the differences in our bedrock, Steve is going to take us back. Like, way back: “Roughly 400 million years ago or so.”

Steve says that time period — around 450 million to 320 million years ago — was very dynamic.

“Obviously I'm painting with a broad brush. You know, we throw around numbers of plus or minus 20 million years, which is a very long time,” he says.

About 400 million years ago, Vermont and New Hampshire were far apart, separated by an ocean. Vermont was at the edge of a supercontinent called Rodinia, right up to the state’s eastern border, about where the Connecticut River now lies.

“Vermont was coastal property,” Steve says. “There wasn't anything to the east of Vermont.”

Steve says that off the coast, there were islands and micro-continents “that were rafting off of proto-Europe and proto-Africa.”

Those land masses drifted towards what’s now Vermont — and then slammed into it. And that’s what created the eastern section of New England, including New Hampshire.

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The next key difference between the bedrock — and then the mountains — in Vermont and New Hampshire is the way in which they formed. To understand that, we need to remember some basic geology.

"If you go back to earth science that you took in ninth grade, or college, and you remember the layers of the rock — so crust, mantle, core. The crust is what we call the bedrock,” says Laurie Grigg, an assistant professor in the Department of Earth & Environmental Sciences at Norwich University. “And that’s that outer rigid layer. So we’re on the continental crust.”

The crust. When the land masses that now make up Vermont and New Hampshire collided, as Steve Trombulak described, Vermont was higher in the crust than New Hampshire.

“And as a result, the rocks in Vermont have undergone less metamorphism, because they were higher in the crust, which is not as hot, and not as much pressure as rocks in New Hampshire, which were lower in the crust and kind of more in the center of this continental collision that was occurring,” Laurie says.

This is where it gets a bit confusing. Metamorphism means change — and even though Vermont rocks underwent less change, a lot of the bedrock here is still referred to as “metamorphic rock.” Whereas a lot of the bedrock in New Hampshire is igneous rock. Laurie Grigg has a helpful way of explaining the difference. She calls it the folds versus the blobs.

Folds and blobs

“The metamorphic rocks that are fairly well beat up in Vermont have been folded,” Laurie says. “So you can think of, if you take a piece of paper, and you push it from either side, then it’s going to fold into multiple ridges up and down. So essentially, that’s what happened."

When the ancient islands slammed into what’s now Vermont, the land folded up into mountains.

“All of that slamming into North America over a relatively short period of time led to the creation of the Green Mountains and the Taconic Mountains, the Appalachian Mountains all the way down as far as Alabama,” says Steve Trombulak. “All of that was a result of the ancient collisions.”

That slamming, then folding up, created the Green mountains and the long north-south valleys and rivers in Vermont:

This bedrock geologic map shows the folded bedrock that creates Vermont's long north-south valleys, as well as some blobs of bedrock in the Northeast Kingdom.
Credit Vermont Department of Environmental Conservation / Agency of Natural Resources

(View the full-sized, zoom-able map & legend at the Department of Environmental Conservation.)  

Laurie Grigg lists a few: “the Mad River, the Stevens branch of the Winooski, the Kingsbury branch, Waterbury — those drainages are following these north-south trending valleys that have been produced by these long linear lines of rock types in Vermont.”

Meanwhile, in New Hampshire — and parts of Vermont’s Northeast Kingdom — where the rock was lower in the continental crust, there was something bubbling under the surface.

“So, in New Hampshire, instead, we’ve got … many many big giant blobs of granite, which is a different kind of rock. It’s an igneous rock, which means it formed from a magma,” says Laurie.

Magma is molten rock — and in this case, big blobs of it intruded into the crust, and melted part of it, and then everything cooled, forming a different kind of mountains.

“So we don’t really see these long linear valleys that are kind of the length of the state in New Hampshire because of the big massifs, the White Mountain massif and other ones,” Laurie says. “And so the whole weathering pattern and pattern of the topography is really different.”

Credit New Hampshire Department of Environmental Services

So that’s what forms the basis of what we see today in Vermont and New Hampshire. The Green Mountains of Vermont were folded up from a continental collision. And the granite of the White Mountains formed from blobs of magma bubbling up and cooling.

The folds and the blobs eventually shaped human development, too. We’ll get to that later. But first, we’re gonna jump ahead — by millions of years — to the Next Big Geologic Thing in this region that made the landscape the way we know it today.

The Ice Age

Starting about 2.5 million years ago, ice consumed most of northern North America.

“So picture this gigantic ice sheet 1 to 2 miles thick coming down across the landscape,” says Steve Trombulak.

Over the last 2 million years, the ice came down from the north, then retreated back, then pushed down again — more than a dozen times.

“A whole lot of what was here was just scraped bare as the ice sheet retreated,” Steve says. “Each time it retreated it was leaving behind a completely bare landscape. All that was left was bedrock and scattered boulders.”

In geologic time, the glaciers’ final exit from Vermont wasn’t all that long ago — about 12,500 or 13,000 years ago.

And as the ice melted, something interesting happened on the western side of Vermont: The melting water got stuck behind the glacier, as it tried to flow north. This created something called a pro-glacial lake.

“It’s a lake that's sitting up against a glacier,” Steve explains.

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The glacier kept melting, but remember, it’s 1 to 2 miles thick! So all that weight was pushing down the continental crust.

“But because the crust was so depressed below where it is today … the Atlantic Ocean actually rushed in up the valley that is made by the St. Lawrence River today,” Steve says.

Creating an inland sea, covering what’s now Lake Champlain and the Champlain Valley. So for several thousand years, before much of the water drained out, sediment flowed down off the Green Mountains and settled to the bottom of that sea.

“And you get a thick soil that was nutrient-rich, heavily made up of clays,” Steve says. “We see a lot of clay in the Champlain Valley soils today.”

Now, those of you who are closer to the Vermont-New Hampshire border, don’t feel left out. There was also a glacial lake in what’s now the Connecticut River Valley, called Lake Hitchcock.

“Lake Hitchcock filled the Connecticut River Valley and many of the tributary valleys,” Steve says.

After the glaciers, Vermont and New Hampshire were left with their respective bedrock. And remember, this was only about 13,000 years ago. As the bedrock weathered away, it helped create our soils. And there are some differences to the soil in each state, too. Laurie Grigg says in New Hampshire, it starts with the granite.

“When granite weathers out, it’s going to produce a lot more quartz, a lot more what you think of as sand,” she says. “So, sandy soils are really well drained.”

There are sandier soils in New Hampshire, while Vermont has “what we call rich soils,” Laurie says.

“And they’re rich soils because they tend to be eroding out of this carbonate-rich bedrock. And those things — calcium magnesium, potassium, [carbonate] — are all great nutrients.”

So, that’s what’s been going on underground. Different bedrock, which has given way to different topographies, and different soil.

From soil to state government

But Beagle’s question was also about the above-ground differences — and how geology influences the feel and identity of each place. And to learn more about that, we went to talk to Chuck Wooster, at Sunrise Farm in White River Junction.

Some of Chuck’s CSA members are picking blueberries when we sit down in the shade of his maple sugaring shed. It turns out the topic of Chuck's master's degree research, at Dartmouth College, was pretty much the topic of this episode.

“I got a master of arts in liberal studies to look at how the natural landscapes have affected the cultural landscapes of [Vermont and New Hampshire],” he says.

According to Chuck Wooster, of Sunrise Farm in White River Junction, the differing soil characteristics in Vermont and New Hampshire influenced everything from the states' approaches to state government to their philosophies on an income tax.
Credit Angela Evancie / VPR

Chuck has been farming here since 2000. But Sunrise Farm itself is more than 200 years old.

“It's interesting being a farmer right here, because in the Upper Valley there are farms on both sides of the river,” he says. “From the New Hampshire perspective, this is like the bread basket of New Hampshire. And in the Vermont perspective, ‘Wait, people are farming over there?’ You know, so it's a very different moment, that we're sort of the forgotten piece of Vermont.”

And perceptions like this were what interested Chuck when he began studying how the two states’ literal landscapes affected their cultural landscapes.

“I also, as part of my research into the soils, looked into sort of the political history and some of the cultural differences that got the two states to this place,” he says. “And now it's at this point that people really select states based on their preconceived values. Vermont, you have a very strong community tradition, a belief in sort of the community informally or the government more formally as something that's available to help solve problems, that's a positive force in people's lives. And in New Hampshire, you have much more of a sense that, you know, things maybe at the town level should be solved, but really government should be minimal and that shouldn't be something that we look to for a source of solutions.”

Now, extrapolating politics from bedrock can be tricky business. But according to Chuck, as far as European heritage goes, a lot of the differences between Vermont and New Hampshire can be traced back to three big factors.

“One is the soil. One is the coastline. And one is sort of how the glacial history unfolded in the two states,” he says.

This first one is a review of what we heard from Steve Trombulak and Laurie Grigg — the whole idea that hundreds of millions of years ago, Vermont’s bedrock was higher up than New Hampshire’s. And this gave way to different soils, generally speaking.

“And so the Vermont soil, the Vermont bedrock, is very good for long-term agriculture. On the New Hampshire side, you got much more of like harder minerals and things that eventually got turned into granites and much harder rock, which is not as good for agriculture long term,” Chuck says.

Chuck Wooster holds a handful of soil at Sunrise Farm in White River Junction. Chuck says that even though many of the environmental differences between Vermont and New Hampshire have become blurred in the age of fossil fuels, many cultural perceptions endure.
Credit Angela Evancie / VPR

Different soil characteristics also influence which trees grow best in each state.

“We think of the iconic trees of the two states. In Vermont, obviously the sugar maple, which plays into the whole tradition of farming and the sort of sustainability on the land,” he says. “The real amazing trees of New Hampshire are white pine and white oak.”  

And it all goes back to the bedrock, and how it’s weathered.

“Sugar maple really loves a ‘sweeter’ soil, which is to say more calcium, and so hence it does so well in Vermont and not as well in New Hampshire. Meanwhile, white pine in particular tends to out-compete other species on the more well-drained acidic sites,” Chuck says. “White oak to some extent also does better on some of those sites.”

The other two factors Chuck mentioned were coastline and glacial history. And he has a pretty interesting theory about how those things eventually shaped how Vermont and New Hampshire approached state government.

Remember that inland sea in the Champlain Valley? The one that was created by Ice Age glaciers? Chuck says that after the glaciers receded, it took a few thousand years for the sea to become a lake: Lake Champlain. No more coastal connection. And this happened a few thousand years before the Europeans sailed over to the New World. In human terms that’s a very long time, but in geologic terms, Chuck says it’s like a blip.

“So that sort of seemingly minor detail of geology ended up occurring right before the Europeans came and sailed to to the New World,” he says. “And so ... if European colonization had occurred, you know, only a few thousand years earlier, they could have actually sailed right into Burlington from Europe.”

"If European colonization had occurred ... only a few thousand years earlier, they could have actually sailed right into Burlington from Europe." — Chuck Wooster, Sunrise Farm

You know what they say: Geologic timing is everything. And when the Europeans got here, Vermont’s coastline was no more. And then, by the time both our states got around to writing our constitutions, in the late 18th century, we were pretty different.

“At that time, European settlers had lived in New Hampshire for almost 200 years at that point, because they had arrived in the very early 1600s and started settling on the seacoast,” Chuck says.

The white pine and white oak that like New Hampshire soil supplied a thriving ship-building industry — the former for masts and the latter for planking, according to Chuck.

“So in New Hampshire you actually had a quite diverse population," he says. "You had sea captains and merchants and mariners on the coast, you had some farmers moving inland. On the Vermont side, same time period, Europeans had only been living in Vermont for really only 20 years. And the people who lived in that time of European descent were basically almost all subsistence farmers.”

Farmers in small communities, tucked into the north-south valleys created by Vermont’s folded bedrock.

“So when the two constitutions were written they were written very differently, because the people writing them were very  different,” Chuck says.

In New Hampshire, Chuck says that factions from various industries wrote a state constitution that made the government complicated, “and relatively inefficient on purpose. So if your goal is to use government as a tool to solve problems or to to drive or effect social change, it's very complicated to do that in New Hampshire.

“Meanwhile, in Vermont, the constitution was very straightforward. In fact, there was no Senate originally; there was just a House and a governor and the towns were given extraordinary power, which you've probably heard about. Every town had one vote.”

So that’s Chuck’s theory about our state constitutions — that you can trace the different philosophies all the way back to the fact that New Hampshire had a coast when the Europeans arrived, and Vermont didn’t — even though on a geologic time scale, we almost did.

The income tax

Chuck also has an interesting theory about how a kind of geologic politics gave way to one of the most cited differences between our states: the income tax. Vermont has one, New Hampshire doesn’t.

For this we fast-forward to the early part of the 20th century, during what’s known as the Progressive Era.

“A lot of states adopted income tax at that point. And Vermont did so not too long after the flood of 1927,” Chuck says. “There was a great need for revenue at that point, and the farmers — who had tremendous power in the Legislature because every town had one vote, and most towns had farmers — they said, ‘Boy, we're going to pass this thing, because the folks in Burlington and Rutland are going to have to pay it because they work in the mills. They have income, but we're farmers. We have land.’ So the income tax passed in Vermont really as a way to try and stick it to the the blue collar working Democrats in the cities."

Around this same time, in New Hampshire, there was also a push for an income tax. But it failed.

Because of New Hampshire’s complicated constitution, state lawmakers couldn’t approve an income tax on their own; they needed to put the matter to voters in a constitutional referendum. It required two-thirds support, or 67 percent.

"That's where that soil made a huge difference. If New Hampshire had had all the farmers ... then presumably then the income tax would have passed [in the 1920s]."

There were three of these big votes between 1920 and 1930. One had just over 50 percent support, and one had 60 percent support.

“Which would have been enough in any other state to have it enacted. But in the case of New Hampshire it wasn't enough,” Chuck says.

So, no dice on the income tax. New Hampshire has rejected the tax many more times since then, but Chuck traces those Progressive Era votes back to the soil.

“A lot of the the people who worked in the mills in Manchester and all down the Merrimack River had a lot of power and were able to turn it back, so that's where that soil made a huge difference,” he says. “You know, if New Hampshire had had all the farmers, if that power had been vested in them, then presumably then the income tax would have passed at the same time.

“It’s super interesting, and now we live in this age of fossil fuel where these types of differences between the states don't really matter, because if you're a farmer and your soil is not good, you can buy fertilizer, you can move between states. And so those differences become blurred. And now the difference is really cultural, this perception of the two states and how they're different. But there was a time when those details had made a huge difference in terms of creating sort of a government and the social character that we see today.”

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Now, like Chuck says, a lot of Vermont and New Hampshire’s geologic differences eventually became blurred. But some of them persevered. For example, New Hampshire’s more blobbed topography made it easier for mills to do business with Boston and New York.

“You could have a mill, and we certainly had plenty of textile mills and other kinds of mills in Vermont that were just never as big as the ones in Nashua or Manchester, New Hampshire,” says Middlebury College professor Chris McGrory Klyza, the second author of The Story of Vermont, along with Steve Trombulak, whom we heard from earlier.

Chris points out that because of Vermont’s terrain, a lot of places still have that you-can’t-get-there-from-here feeling.

“In southern New Hampshire, it's pretty easy to move kind of east-west, and that's really not true anywhere in Vermont,” he says.

And Chris says Vermont’s topography — and our roots in agriculture — have become a part of something much bigger: our identity.

"We are a rural state that wasn't tied to manufacturing, wasn't tied to big cities, and that continues to kind of shape who we are, I think." — Chris McGrory Klyza, Middlebury College

“The importance of farming culturally I think today far supplants its importance economically," he says. "But you know, if you read the paper, or listen to VPR, or follow what's going on in the Statehouse, agriculture is very, very important. And I think a lot of that has to do with, we are a rural state that wasn't tied to manufacturing, wasn’t tied to big cities, and that continues to kind of shape who we are, I think."

State character aside, Laurie Grigg, of Norwich University, says our geology has unquestionably shaped the landscape that so many of us respond to when we drive across the state border.

“I think that Vermont has a, like, gentle beauty that’s a little bit different than other places that are also beautiful but I maybe wouldn’t use the word gentle to describe them," she says. "We’re a really weathered, old landscape. And so I think that is what you feel in Vermont. It’s nice and gentle and pretty. Nice and rounded, and serene. And that makes sense with what’s underneath.”

Brave Little State is a production of Vermont Public Radio. We have support from the VPR Journalism Fund, and from Shacksbury Cider. And from VPR members. If you like this show, consider becoming one.

A very special thanks this month to Andy Friedland, Mary Searles, Paul Rumley and John Dillon.

Our editor is Lynne McCrea and our theme music is by Ty GibbonsOriginal scoring this month by Liam Elder-Connors. Other music in the episode was used under a Creative Commons license: