[A map in the upper left corner of the marker shows the extent of glaciation over North America and Wisconsin's position. Below it, a map shows the extent of glaciation in Wisconsin, with the locations of National Scientific Reserve Sites (Interstate, Chippewa Moraine, Mill Bluff, Devils Lake, Cross Plains, Horicon Marsh, Campbellsport, Kettle Moraine, and Two Creeks).]
Deep winter in Wisconsin lasts about three months. But during the last two million years, dramatic shifts in climate produced periods with longer winters. These cold spells lasted thousands of years. As snow accumulated an ice sheet formed and grew to cover most of Canada and Northern United States.
The last great episode of the Ice Age ended about 10,000 years ago. Called the "Wisconsin Glaciation," it radically altered this landscape. Creeping ice excavated vast quantities of rock and soil. When the ice melted, the debris it carried was deposited to form an amazing variety of glacial features.
[At the top center of the marker is a graphic illustrating the following glacial features: Glacial lake, esker, kame, drumlin, kettle lake, end moraine, and outwash plain.]
Prominent Glacial Features
[A chart lists which features (glacial lakes, potholes, eskers, meltwater gorges, kames, drumlins, kettle lakes, moraines, outwash plain, buried forest, and erratics) are present in the listed National Scientific Reserve Sites (Interstate, Chippewa Moraine, Mill Bluff, Devils Lake, Cross Plains, Horicon Marsh, Campbellsport, Kettle Moraine, and Two Creeks).]
Ice Age National Scientific Reserve preserves evidence of the great glaciers. The Reserve consists of nine sites administered by the Wisconsin Department of Natural Resources, in cooperation with the National Park Service. Here, present and future generations may study and enjoy their glacial inheritance.
Devils Lake Unit
[Map of unit.]
Millions of years ago, an ancient river flowed through a deep gorge here in the Baraboo Hills. But Ice Age glaciers dammed up the gorge with glacial moraines to form Devils Lake, one of Wisconsin's most spectacular features.
Today, the Devils Lake Unit is an excellent place to study the effects of the continental glaciers. Hiking trails lead to intriguing rock formations and level views of the lake. Recreational facilities here and on the North Shore rest on glacial moraines and outwash deposits.