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Natural History

Vermont's eighteenth century colonists arrived in a landscape shaped by more than a billion years of continental movement and collision, volcanic activity, erosion and sedimentation, as well as twelve thousand years of habitation by native peoples. The Champlain Basin in particular has seen some of the most dramatic changes in New England's recent geological history, and was a preferred site of settlement for native peoples and European colonizers alike.

Mountain Building and Ice Ages

The history of the Champlain Basin begins about one billion years ago with the first of three major mountain building events, called orogenies, that determined northeastern North America's bedrock geology. These orogenies, instigated by collisions of continental plates, spanned hundreds of millions of years, generated enormous amounts of heat and pressure, and created the massive mountain ranges, as well as the saltwater-filled valley, that would eventually take on the shape of the Lake Champlain Basin.

After this period of continental unrest, the next major geological force to move upon the Champlain Basin was an immense sheet of ice. The most recent Ice Age began about two million years ago when the Earth's climate shifted dramatically, snow began to accumulate, and compressed piles of snow turned into huge sheets of ice. Glaciers exerted tremendous pressure on the land, scraping and scouring it down to the bedrock as they flowed slowly south; furthermore, glaciers carried away the eroded materials, and dropped them elsewhere whenever the climate shifted and the ice began to melt.

Camel's Hump, Green Mountains, Vermont

Camel's Hump in the Green Mountains owes its distinctive shape to glaciation. The glacier advanced gradually over the northern side (on the right in this photograph) and scoured the southern side down to bedrock, leaving a steep slope in its wake. National Park Service

For tens of thousands of years, Vermont was buried underneath a massive glacier as much as a mile thick. Then, beginning about 20,000 years ago, another dramatic climate change caused the northward recession of the glacier covering northern North America. Glacial meltwater filled the entire Champlain Basin between the Adirondack and the Green Mountains with a vast freshwater lake—Lake Vermont, which flowed south into the Hudson River Valley. [Lesson What's in the Basin?] The melting glacier also left behind material debris it had picked up on its way in; glacial deposits ranged in magnitude from massive boulders and cobbles to fine sands and silt. The fertile clay soil of Addison County, celebrated by so many of its local historians, is the finest sediment of Lake Vermont, laid down tens of thousands of years before European settlers arrived in the Champlain Valley.

End of the Ice Age and Beginning of Human Habitation

When the melting glacier had retreated northward beyond the present-day Canadian border some 13,500 years ago, the character of the Champlain Valley again changed dramatically. Saltwater from the Atlantic Ocean flowed into the Champlain Basin via the Saint Lawrence River Valley, and freshwater Lake Vermont was replaced by the smaller Champlain Sea, a northern extension of the Atlantic. With the complete recession of the glacier, the Champlain Lowlands began to fill with life: the developing tundra ecosystem supported low-lying plants, insects, rodents and herds of mammoths and caribou, as well as the region's first human dwellers, the nomadic Paleoindians.

Lake Vermont Champlain Sea Physiographic Regions of Lake Champlain

The three major bodies of water that have occupied the Champlain Basin. Click on images for larger views. Lake Champlain Basin Program/Northern Cartographic

The "marine invasion" lasted about 2,500 years, until post-glacial rebounding at the northern edge of the Basin closed it off to the Ocean. The Basin then filled with rainfall and riverwater and became home to freshwater Lake Champlain in its present form, flowing north to the Richelieu River and to the Saint Lawrence River beyond. Trees appeared and closed forests developed—this was the birth of the forested landscape eighteenth century European settlers encountered some ten thousand years later. The new forested environment of the Champlain Valley was home to the "riverine" Archaic people, who hunted, fished and gathered seasonally within defined territories. The Champlain Lowlands provided its mobile hunter-gatherers with abundant food resources, and environmental historians Christopher Klyza and Stephen Trombulak emphasize that the development of agriculture during the later Woodland period "never eclipsed the reliance on wild food." Hunting and gathering persisted as the primary mode of subsistence for the Abenaki, who inhabited the Champlain Valley at the time of Samuel de Champlain's arrival in 1609.

Ecological Revolutions

By all accounts, the arrival of Europeans in northern New England signaled the beginning of a series of ecological revolutions. European settlers brought to the New World not only foreign organisms such as cows and wheat, but also foreign notions of government, religion, commerce and land-use. Klyza and Trombulak describe European colonists as viewing their relationship to the land as "fixed—not mobile" and the land itself as requiring improvement through cultivation. Vermont's famous nineteenth century naturalist George Perkins Marsh voiced general sentiment when he commended farmers in Rutland County for effecting a "marvellous change, which has converted unproductive wastes into fertile fields, and filled with light and life the dark and silent recesses of our aboriginal forests and mountains."

So it was with complete confidence in the moral value of their endeavor that European settlers transformed 'virgin' lands into a tidy network of bustling villages and fruitful farms. [Lesson Clearing the Land] The transformation was rapid and its effects irreversible. Environmental historian Carolyn Merchant explains that "what took place in 2,500 years of European development through social evolution came to New England in a tenth of that time through revolution." By 1800, some thirty years after the first wave of settlement in the Champlain Valley, huge tracts of forestland had been cleared, once-abundant wildlife populations were diminished, and Vermont's climate, as well as the character of her soil and her waterways, had changed perceptibly. The Champlain Valley had entered a new era, in which humans were the agents of dramatic changes in the natural world. [Lesson Change Over Time: Vermont Wildlife]

In the centuries that followed the settlement period, new cultural forces impacted the way humans interact with land in the Champlain Valley and throughout northern New England. Westward expansion into the fertile Middle America states and the development of new technologies such as the railroad signaled the beginning of significant shifts in regional and national economies, which in turn affected local growth patterns and land-use policies. At the same time, increased ecological awareness, best represented in the person of George Perkins Marsh, gave rise to reforestation efforts and to the establishment of wilderness preserves such as the Green Mountain National Forest. [Lesson Meet Vermont's Naturalists] Scientists, historians, lobbyists, legislators and naturalists such as Marsh enlarged public knowledge of our role in a complex ecological system, conceding that the effects of the colonial ecological revolution continue to shape the landscape: at the commencement of the new millenium, humans remain the most significant agent of change in the natural world.