About that time, a major climate change started taking place. Northeastern Canada started getting lots of snow - LOTS of snow! The snow built up year after year, to the point where it became so heavy and dense, it became ice. The ice started flowing, like if you took pudding on a plate and kept adding more on top of it - it OOZED. After many thousands of years, the ice (called a glacier ) oozed its way into Illinois, as well as most of the northern part of North America.
