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
Glacial survival hypothesis Glacial survival hypothesis According to the northern cryptic glacial refugial hypothesis (or glacial survival hypothesis), during the last ice age cold tolerant plant and animal species (e.g. Norway spruce and Norwegian lemmings) persisted in ice-free microrefugia north of the Alps in Europe. The alternative hypothesis of no persistence and postglacial immigration of plants and animals from southern refugia in Europe (southern refugia paradigm) is sometimes also called the tabula rasa hypothesis. Over the past plants and animals have persisted through long periods of climate change including several glacial and interglacial periods. There is a long-standing debate on what happened to