Wisconsin glaciation

The Wisconsin glaciation extended from about 75,000 to 11,000 years ago, between the Sangamonian Stage and the current interglacial, the Holocene.

This glaciation radically altered the geography north of the Ohio River, creating the Great Lakes.

At the height of the Wisconsin Episode glaciation, the ice sheet covered most of Canada, the Upper Midwest, and New England, as well as parts of Idaho, Montana, and Washington.

On Kelleys Island in Lake Erie, northern New Jersey and in New York City's Central Park,[2] the grooves left in rock by these glaciers can be easily observed.

As the ice sheet would continue to melt and recede northward, these ponds combined into proglacial lakes.

Thus, sand and gravel landforms developed along the sides and front of the ice sheet;[3] elongated accumulations of this material are known as kames.

[3] The materials left under the glacier when it melts back is called the ground moraine or till plain.

A number of scientific studies have been conducted to determine species distribution, particularly during the Late Wisconsin and early to mid-Holocene.

Here in the Waterman Hills researchers found that Juniperus osteosperma and Pinus monophylla were early to mid-Holocene dominant trees, while Monardella arizonica has been a continuously present understory plant.