The Ice Age Revisited
Our prehistoric SuperGraphic journey will take us back in time beyond 10,000 years to the end of the last great ice age. This period is known formally as the Wisconsinan Glacial Episode and was the most recent major advance of the North American Laurentide ice sheet during the ice age. Massive sheets of glacial ice covered hundreds of thousands of square miles, including most of Canada and a large portion of the northern United States. During this last glacial episode, the maximum ice extent occurred approximately 21,000 years ago during the last glacial maximum (LGM), known as the Late Wisconsinan. We know today that the Wisconsinan glaciation period dramatically altered the geography of North America. The advance of continental glaciers and lowering of sea levels created a land bridge for migration of mammals to and from Asia and North America. Today, most archeologists and other scholars agree that it was across this land bridge during the Late Wisconsinan that humans first passed to and from Asia into North America. Fossils on both sides of the land bridge tell scientists that animals crossed back and forth between the continents here for thousands or millions of years.