The Ancient Lake Beneath Your Wheels
Near Burlington, Vermont
The ground you're driving on was once the bottom of an ocean.
About thirteen thousand years ago, the great Laurentide Ice Sheet that had buried this entire valley under more than a mile of ice began its final retreat northward. As it pulled back, the land was so compressed by all that weight that it sat far lower than it does today. Sea water from the Saint Lawrence estuary poured in and flooded the valley, all the way south past present-day Burlington. Scientists call it the Champlain Sea, and for roughly three thousand years, beluga whales, Atlantic cod, and ringed seals swam over what is now the Interstate Eighty-nine interchange.
The proof is still sitting in a museum right here in Burlington. In eighteen forty-nine, railroad workers digging near Charlotte, Vermont, pulled a nearly complete beluga whale skeleton out of a field. It now rests at the University of Vermont, a silent ambassador from a time when Vermont had a coastline.
Then the land rebounded. Freed from the crushing weight of the glacier, the crust slowly rose, cutting off the connection to the Saint Lawrence around ten thousand years ago. Freshwater from rain and snowmelt replaced the salt water, and the Champlain Sea became Lake Champlain.
The lake today is still remarkable, running nearly one hundred twenty-five miles from north to south, shared by Vermont, New York, and Quebec. The cliffs at Rock Point on Burlington's northern shore expose the seam of that ancient story, a five-hundred-million-year-old dolostone shoved up over younger shale by a thrust fault, then polished smooth by glacial ice, then lapped by a saltwater sea, then the freshwater lake you see today.
Every layer of rock here is a chapter. Burlington sits on a geological autobiography written in the language of time too deep for ordinary imagination.
