I drove to the Champlain Islands to visit the Fisk Quarry Preserve, an old limestone quarry on Isle La Motte that is part of the “oldest known biologically diverse reef in the world”: oldest meaning the reef formed 480 to 450 million years ago. Isle La Motte is seven miles long and three miles wide, has 500 year-round residents and many interesting natural and human histories to tell.
On the southern third of the island is one of the best examples that can be seen of an ancient reef—called the Chazy Reef—that once spanned 1000 miles from Newfoundland to Tennesee. Millions of years ago this entire area was located on a continental shelf in the southern hemisphere submerged in shallow, warm waters. Communities of organisms beginning with bryozoa that predated corals colonized and built the reef. The bryozoa can now be seen as fossils in the oldest layers of limestone that make up the bedrock of the island. (Limestone is a sedimentary rock that forms from the accumulation of marine sediments such as shells, coral, algal and fecal debris, or from the precipitation of calcium carbonate from lake or ocean water.)
Middle layers of the ancient reef are made up of fossilized stromatoporoids, large cabbage-like animals that are ancestors to sponges: this layer can be viewed at the Fisk Quarry. The youngest reef layers “represent the world’s earliest appearance of a complex reef-building community, with the framebuilders consisting of a diverse community of stromatoporoids, lithistid sponges, tabulate corals and bryozoa.” This layer can be viewed on the Goodsell Ridge Preserve, a little north of the Fisk Quarry. After 5 million years in the southern hemisphere, plate tectonics were responsible for moving and rotating the land mass that included Vermont to the northern hemisphere, and subjected the reef formation to forces that tilted it, enabling us to see these amazing layers.
The Fisk Quarry Preserve is one of two quarries on the island preserved through the efforts of the Isle La Motte Preservation Trust. Both quarries were dedicated in 2009 as National Natural Landmarks. During the 19th century these quarries were very active, and the black and grey limestones from them were used in the Vermont State House, Radio City Music Hall and the National Gallery of Art. In the 1990’s a small company purchased the Fisk Quarry and began mining it again after 70 years of inactivity. An island resident named Linda Fitch initiated a fundraising program to purchase the land, which lead to the formation of the Preservation Trust. Their mission is to not only protect the reef but to encourage scientific research, education and conservation of the local natural resources on the island.
It is amazing to see the fossil remnants exposed in the limestone blocks and walls of the quarry, but to also imagine the forces that moved land masses thousands of miles, and how much Vermont has changed over millions of years!
In terms of human history, Isle La Motte was the first landing place for the first white explorer—Samuel de Champlain—in 1609 as he traveled with Indian guides from Quebec into Vermont, via the lake that he would eventually name after himself. A French expedition lead by Captain La Motte built the first permanent settlement on the island in 1666, Fort Saint Anne (named after the mother of the Virgin Mary). In that same area today stands an outdoor chapel and shrine established in 1892 and run by the Society of Saint Edmund, or the Edmundites.
A favorite bike ride of mine—”the island ride”—begins in South Hero and continues through Grand Isle, North Hero, and then follows the road around Isle La Motte before returning for a total of 50 miles; the ride usually includes a head wind up and back. The loop around Isle La Motte is special because it is almost car-less, turns into dirt for a portion, and follows the west coast of the island for great views of the lake.
Afterward I visited Alburg Dunes State Park, which you drive by on the way to Isle La Motte. The park was created to protect the beach—the largest stretch of natural sand beach in Vermont —and dunes, which “together make up what is known as a barrier island, geologically similar to coastal formations more common along ocean shorelines. The sand has come from a layer of glacial till, the soil that was left atop the low bluffs southeast of the beach when the last glacier melted. The bluffs have eroded over thousands of years, and the soil carried off by lake currents. Sand from that soil settles out in the pocket between the rocky “Point of Tongue” to the east and “Coon Point” to the west, forming the beach. Prevailing southerly winds, in the late summer and fall when lake levels are the lowest, blow the sand back from shore, forming dunes. It’s a barrier between the lake shore and the wetland behind, and an island because the beach and dunes, however slowly, continue to migrate into and over the wetland.”
This remnant of the last glacial period in Vermont was disturbed quite a bit by bulldozers, tree cutting and walking on the dunes before being protected as a park, and when you walk along the beach you will notice fencing was erected to protect the dunes from further erosion. I have no desire to walk in the dunes anyway because they are covered with poison ivy! There are a few rare plant species that grow on the dunes, and I was able to observe two of them: Beach Pea, Lathyrus japonicus, and Champlain Beachgrass, Ammophila champlainensis.
Another unique feature of the park is the presence of “the 283-acre South Alburg Swamp, located just north of the sand beach and dunes. It is a forested wetland complex that includes a black spruce bog, northern white cedar swamp, tamarack swamp and red maple swamp”. Core samples taken from the black spruce bog give climate and vegetation information dating back to the last glacial period.
An interesting weather phenomenon occurred while I was exploring the quarry, in the form of an intense storm that came across the lake with what felt like gale-force winds and torrents of rain. The air temperature dropped about 20 degrees in a few minutes—from 60° to 40° F—branches were blowing off trees right and left and the whitecaps on the lake were a few feet high. I felt very sorry for a sailboat that was caught on the lake trying to make it back to shore before capsizing!