Last Glacial Period River, which in turn was formed during an earlier glacial period. In its retreat, the Wisconsin Episode glaciation left terminal moraines that form Long Island, Block Island, Cape Cod, Nomans Land, Martha's Vineyard, Nantucket, Sable Island, and the Oak Ridges Moraine in south central Ontario, Canada. In Wisconsin itself, it left the Kettle Moraine. The drumlins and eskers formed at its melting edge are landmarks of the Lower Connecticut River Valley. In the Sierra Nevada, there are three named stages of glacial maxima (sometimes incorrectly called ice ages) separated by warmer periods. These glacial maxima are called, from oldest to
Buried valley Europe. Recently, research has been focused on understanding the sedimentology of these formations in an effort to determine the safety of continued use of the aquifers which are often found in them. Buried valleys are created when ancient river or stream valleys are present that predate the most recent glaciation, and since have been filled with glacial till and/or outwash. In the Pleistocene, advancement and retreat of glaciers carved out the preexisting valleys, and deposited the material that had accumulated in the glacier by the melting of either the glacial outwash or the melting of the ice that composed the