A Visit To Southington’s Great Unconformity
- Philip Thibodeau
- Jan 7
- 5 min read
Updated: Jan 7
There is no path to Southington’s Great Unconformity. Instead, visitors must tread carefully over boulders and through stands of oak and mountain laurel until they come to the edge of a steep ravine. There the ground drops away to reveal Roaring Brook splashing over mossy rocks, forming a series of small waterfalls on its way to the valley below.
One cold Saturday morning in late December, a group from the Southington Land Trust made a journey to this ravine. The view and the hypnotic trickle of the water were charming enough - yet that was not all they had come to see. On the far side of the stream rises a rock formation that looks like two different types of cake stacked on top of each other. The upper layer is more rusty in color with horizontal bands, while the lower one is grey and juts up vertically like a row of blunt teeth.
This rock formation, the Great Unconformity, was the goal of their visit.
Many residents know that Southington has an ‘unconformity’ – it is even mentioned on the town’s Wikipedia page. But what is it, exactly?
A Short History of a Long Past
An ‘unconformity’ is any place where two masses of bedrock that differ radically in age and origin touch, without any layers from the time in between. Most unconformities lie deep underground, covered by topsoil. They only become visible when some natural force, like Roaring Brook, cuts a channel to expose them.
These junctions have a story to tell about earth’s deep past. The story of our town's unconformity begins with the lower layer of rock, which is the older of the two. It dates to a time about 400 million years ago when the highest forms of life on earth were fish and plants. At that time, all seven of the earth’s current continents formed a single giant landmass called Pangaea. A massive mountain range stretched across its northern parts as tall as the Alps and twice as long – a range that survives to this day, in diminished form, as the Appalachian Mountains.
The land that today we call Connecticut was located just south of the center of that range. The grey rock one finds in the Unconformity and elsewhere on Southington Mountain once belonged to these mountains. For the most part it is a mix of whitish quartz and glittering mica:
Now the next chapter in our story unfolds. About 200 million years ago, just as dinosaurs were beginning to take over the earth, an enormous crack developed in the middle of Pangaea, just east of the mountain range. It grew and filled with seawater, splitting Pangaea into the separate continents of North America and Africa. Eventually that gap would expand to become what we now call the Atlantic Ocean.
Around the same time, a set of smaller cracks opened in the middle of future Connecticut. There the earth sank down to form the Connecticut River Valley, which stretches through the middle of the state from New Haven to Windsor Locks, and includes most of Southington. What started as a marine inlet eventually filled in with sediment washed down from the surrounding mountains.
In time, this sediment was compressed into a soft, rust-colored sandstone known as arkose. Most of the bedrock in the middle of Southington is a layer of arkose resting on the grey rock below, like a mud pie in a stone bowl.
Over the next hundred million years, the floor of the valley slowly tilted, with the western half rising and the eastern half sinking. (You can still see this tilt when you are driving on I-691 in Meriden, in the slanted cliffs under Castle Craig.)
When the western part rose it lifted the valley floor. The rock formation at the Unconformity is a part of that floor - a place where a piece of mud pie touches the bowl. In short: compacted marine sediment above, and the remnants of an ancient mountain range below.
The Unconformity And The Southington Land Trust
Southington’s Unconformity is a rare natural wonder, not unlike the dinosaur footprints that are the pride of Rocky Hill’s Dinosaur State Park. However, rock masses are not quite as universally beloved as dinosaurs, and for most of the town’s history, no serious effort was made to promote or protect the site.
In 1972 the question of preservation became an urgent one when a developer named Gerald Griffin purchased the land near Roaring Brook in order to build there. The members of Southington’s newly-formed Conservation Commission tried to see what they could do to protect the site. Griffin, while unwilling to donate the land outright, was lured by the promise of tax incentives to grant an easement for the lot containing the Unconformity. Under the terms of this easement, the stream and the rocks would remain untouched in perpetuity.
All that was needed to seal the deal was an entity to hold the easement. And so one was formed: a nonprofit corporation called the Southington Land Conservation Trust. The trust was headed by Luis Lozano, the Commission's chair, and officially recognized by the IRS in 1974.
Today the Unconformity lies on private property; a chain-link fence, dense shrubs, and ‘no trespassing’ signs serve to discourage unannounced visitors. However, the Trust continues to be responsible for inspecting the property, to make sure it remains undeveloped and has no issues with trash or invasive species. To fulfill this obligation, members visit the site twice a year.
A Family At The Rocks
On the day of the visit, Paul Sulzicki, a Land Trust member who lives on Mt. Vernon Road, brought his whole family – wife Erica Bovino, father-in-law Severino, and their children Jack, Stella, and Hazel - to enjoy this rare opportunity.
“We were here many years ago, before the kids, and we thought this was a great opportunity for them as well to learn about history and nature, so we can protect it and be a good steward. Here we all are, from seven years old to eighty – what is it, Dad?”
“82,” said the elder Severino, smiling.
“Seven to 82. Just so appreciative of what’s around us. The monumental forces at play, that created this, are just amazing.”
Erica noted that there is more to the site than geological history: “When we first came through here years ago with the owner’s permission, we saw a bobcat lurking in the shadows over there. There are plenty of bears too - and deer, and turkeys.”
The family spent their visit inspecting the stream and the rocks, sharing recollections of wildlife (including flying squirrels that they spotted in their own back yard), and taking it all in.
Seven-year old Hazel summed up the experience: “It’s really cool. I like the rock, it’s amazing. The waterfall too.”
