sentences:  Other bedrock tunnel valleys lie deep beneath till deposited by the glaciers which created them, but can be traced in many places by the Chain of Lakes in Minneapolis and lakes and dry valleys in St. Paul.North of the metropolitan area is the "Anoka Sandplain", a flat area of sandy outwash from the last ice age.Along the eastern edge of the region are the Dalles of the St. Croix River, a deep gorge cut by runoff from Glacial Lake Duluth into ancient bedrock.