Great Lakes other lakes as "the lower lakes", because they are farther south. Sailors of bulk freighters transferring cargoes from Lake Superior and northern Lake Michigan and Lake Huron to ports on Lake Erie or Ontario commonly refer to the latter as the lower lakes and Lakes Michigan, Huron, and Superior as the upper lakes. This corresponds to thinking of Lakes Erie and Ontario as "down south" and the others as "up north". Vessels sailing north on Lake Michigan are considered "upbound" even though they are sailing toward its effluent current. Lakes Huron and Michigan are sometimes considered a single lake, called
Nipissing Great Lakes both Lake Erie and Niagara Falls would lack the volume of water needed to cut the channel through the Niagara limestone cap rock. Lake Erie was a nonglacial lake in this period. The third stage of nonglacial development ended the Lake Algonquin. A fourth stage was initiated when the upper lakes entered the Nipissing Great Lakes stage and that volume of water was diverted through the outlet at North Bay, Ontario. At this low stage, Lake Erie was to lower than present lake level and which lasted throughout the time of the Nipissing Great Lakes. The Lake Algonquin period of