Valley News – Fossils tell the story of an ancient ocean
ISLE LA MOTTE, Vt. — “You just never know what you’re going to find,” Linda Fitch said, brushing dirt and leaves off a rock at the Goodsell Ridge Preserve, an 80-plus-acre slice of land that she has helped steward for years.
Here, a close read of the landscape tells an ancient story. Some 450 million years ago, the land was covered by a tropical ocean teeming with early forms of life. When these creatures died, their hard shells piled up on the ocean floor, forming part of what scientists consider to be the earliest biologically diverse coral reef on the planet.
Remnants of these life forms are fossilized in rocks at Goodsell Ridge and the nearby Fisk Quarry Preserve, which has long made Isle La Motte — one of Vermont’s most remote communities — a hotbed for geological research and exploration.
“I’m always tempted to pull back sod,” said Fitch, who is the president of the Isle La Motte Preservation Trust. “There’s so much more to be uncovered.”
Last month, Goodsell Ridge opened for the season with seven new interpretive signs that describe the significance of different fossil outcrops at the preserve.
One sign describes some of the creatures that lived around the formation, known as the Chazy Fossil Reef, during what geologists call the Ordovician Period. This includes gastropods, or early snails; cephalopods, ancestors of modern-day squids; and sea sponges called stromatoporoids.
“Time travelers standing here 460 million years ago would have been up to their knees in mud, and the water level would have been up to at least their neck,” it said.
It took a group of volunteers several years to create the signs, Fitch said. The trust does not receive state funding. Instead, it relies on grants and donations.
Chazy Reef originally stretched some 1,000 miles along the continental shelf of ancient North America. Remnants also can be found today in Newfoundland, Quebec and Tennessee, though the most complete fossil record is visible on Isle La Motte.
During the Ordovician Period, the continents were located mostly in the Southern Hemisphere. For instance, North America was near where Zimbabwe is today.
A couple of miles south of Goodsell Ridge is the Fisk Quarry Preserve — and just next door, Fitch owns property including a farmhouse and barn. Through the trees across a narrow, unpaved street, the lot has a sweeping view of northern Lake Champlain.
One time when Fitch was working in her garden, she found a large cephalopod fossil in a chunk of stone. Today that fossil is on display at Goodsell Ridge.
“Cephalopods were kind of the ecological equivalent of sharks,” she said.
The Isle La Motte Preservation Trust purchased Fisk Quarry in 1998 after a yearslong legal battle, Fitch said. Today it’s a public preserve, and many fossils still are visible in the walls and floors, including stromatoporoids, the ancient sea sponges.
Limestone was quarried on Isle La Motte in the 19th and 20th centuries. Stone from the island was used to build Radio City Music Hall in New York and the National Gallery of Art in Washington, D.C., according to the Department of Environmental Conservation.
Fitch said quarrying was a vital part of the island’s economy, but for a long time, locals weren’t as concerned with the geological history contained in the rocks.
“It just happened to have fossils in it,” she said.