The sea drained as the land returned to its original elevation. Clay, silt, sand and gravel attached themselves to the bottom of the glacier which became like a giant scraper with a sheet of sandpaper attached to the bottom. Soft sedimentary rocks were removed creating hollows that are now lakes. Valleys were deepened and widened and all but the tallest mountain peaks were rounded off. A wide variety of physical evidence of the presence of glaciers in the Canadian landscape can be seen today although the ice sheets of the past have retreated to polar regions.
Glacial drift is eroded rock from from one area deposited in other places.
Erratics are huge boulders of igneous rock picked up and deposited in sedimentary basins. Till is a mixture of clay and rock deposited in gently rolling plains when the glacier had picked up more debris than it could carry. Drumlins are oval shaped hills of boulder clay often deposited in groups on till plains. Moraines are long ridges of material deposited at the edge of a glacier that was melting as fast as it was moving out. Spillways are valleys created by the meltwater moving from the edge of glaciers.