You may have never heard of the Niagara Escarpment, but chances are you’ve seen it without even realizing. There’s a ridge that runs from Wisconsin, through Canada and all the way to New York that’s responsible for the Niagara Falls and is formed from the bedrock of the Great Lakes Basin.
Though it may look like a large fault like, it’s actually just the product of unusual erosion. The Niagara Escarpment is also a cuesta, which is a hill or ridge with a gentle slope on one side and a steep slope on the other. Generally, this is because harder rock overlays a softer layer. When erosion exposes the front slope, it called an escarpment.
Depending on how you look at it, the Niagara Escarpment either starts or ends in Wisconsin. It stretches nearly 1,000 miles in an arc across the Great Lakes region, forming the ancient backbone of North America.
This picture is from Ontario, where the ridge is much more pronounced. In Wisconsin, it first shows up in Waukesha County, but is then "underground" - buried by glacial sediment. It re-emerges around Lake Winnebago and continued on up north.
More than 400 million years ago, a shallow sea covered this area. Sediment and the coral of the seabed were compressed over time and formed Dolomite - an extremely hard type of limestone. It's this erosion-resistant material that affected glacial movement. The cliffs you now see are the floors of that ancient seabed. And the limestone that is now part of the Lake Michigan bed is why the bricks created in Milwaukee turned white when fired - and gave us Cream City brick.
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The hard, erosion-resistant rock is actually responsible for splitting an ancient glacier in two and that's responsible for much of the state's eastern geology, including Lake Winnebago and Lake Michigan. The way the escarpment affected glaciers indirectly affected the formation of much of our topography as we know it.
There's actually more than 18,000 acres along the Escarpment set aside by as American Viticultural Area. Nearly 4,000 of those acres are in Wisconsin, where the wine growing season is extended up in this escarpment area thanks to mineral-dense soil and constant air movement from Lake Michigan. The lake produces a situation where warm air over the lake rises, sucking colder air off the land and creating offshore breezes. Cold air cannot settle over the vineyards. The unique mineral content of the soil lends a unique flavor to the grapes.
The Escarpment is home to various flora and fauna not found elsewhere in the country - and in some cases, the world. A cedar found in Brown County is believed to be at least twice as old as any other cedar in the country. The unique soil and climate created by the Escarpment make the land around it fertile in ways no other places are. Here, cedars grow out of the rock along the Lake Michigan coast.
The durable stone mined from around the Escarpment helped early settlers to build and grow. Within two miles of the Escarpment, there are nearly 500 historical sites and structures, giving proof to the resilience of the building material.
