As the ice sheet retreated at the end of the last ice age, it left meltwater in a previously existing low-lying area that was the valley of an eastward-flowing river known as the Erigan River that probably emptied into the Atlantic Ocean following the route of today's Saint Lawrence River. Some geologists think that the Erigan could have been a segment of the preglacial Teays River system. The glaciers destroyed or disturbed most of the preglacial drainage patterns and enlarged and deepened the Erigan basin. Lake Maumee is the first of a series of glacial lakes, which occupied the Erie basin. It was preceded by a few small, disconnected lakes which lay between the ice margin and the southern divide of Erie basin. The name Lake Maumee was first applied in 1888 by G. R. Dryer, of the Indiana Geological Survey, in an official report on the geology of Allen County, Indiana.
Height of water
As the Erie Lobe retreated to the northeast, it left large debris deposits called moraines running at right angles to its line of retreat. One of these, called the Fort Wayne Moraine, was left at the site of present-day Fort Wayne, Indiana, where it acted as a dam that held back the waters of the lake. When the water was at its highest point, about 800 feet above sea level , it left beach ridges that later became the routes of trails and highways. During this stage, the waters of the lake, possibly in response to an advance of the ice front at the lake's eastern end, overtopped a "sag" in the Fort Wayne Moraine. This caused a catastrophic drainage of the lake known as the Maumee Torrent that scoured a one- to two-mile-wide outlet running southwest to the Wabash River known as the Wabash-Erie Channel.
Outlets
The lake's initial outlet was at present day Fort Wayne, Indiana, the lowest place on the border of the basin. Its altitude seems to have been at first about, or above the current level of Lake Erie, but during its life as an outlet, reduced to. At its highest point, the lake used this single outlet. Later, after further ice melt a northerly outlet was reached near present-day Imlay City, Michigan, and lake had two outlets for a short time. The highest beach is to, near the Fort Wayne outlet, In Michigan it is about with areas in Lapeer county its nearly. The Imlay outlet is to above sea level or above the bed of the Fort Wayne outlet. This outlet flowed to the west, into a developing Lake Saginaw and thence into the Grand River Channel. The highest beach is very irregular. The first or highest beach exposure to wave action that the other beaches do not reflect. The second beach is more regular, and on the whole somewhat stronger than the highest. There is a third beach, which is generally weak and in places difficult to trace. The third beach connects with well-defined deltas which the higher levels do not have. The most notable are at the Raisin and the Huron rivers. The third beach is below the Imlay outlet. The outlet at that time may be across the "Thumb" in a lower passage a few miles north. The readvance of the ice sheet may have closed this outlet with a moraine closely bordering the Imlay outlet. The lake beaches, because of their sandy or gravelly constitution, form better lines for highways than neighboring clayey tracts. Thus, early roads followed these natural routes along the lakes. The move to building roads on north and south and east and west lines has led to the abandonment of all or part of these ‘beach’ roads.
The lake retreats in stages
Two later stages of Lake Maumee, had lower water levels because the retreating ice exposed an outlet lower than the Wabash-Erie Channel. The Lowest Maumee drained westward through the Grand River in Michigan and into Glacial Lake Chicago, an ancestor of present-day Lake Michigan. Another advance of the ice blocked that outlet, raising the lake level to about 780 feet ASL, the stage known as the Middle Maumee. A new outlet, the Imlay Outlet, formed that connected with an unobstructed segment of the Grand River farther west. There is enough uncertainty about this sequence that some authorities think that Middle Maumee might have preceded Lowest Maumee. Fluctuations in water level continued through more stages ; Whittlesey, 738 feet ASL; Warren and Wayne, 660–685 feet ASL; and Lundy, 590–640 feet ASL. This see-saw pattern continued until an eastern outlet opened at Niagara, establishing the drainage pattern of modern Lake Erie. This involved the reversal of drainage in what is now northeastern Indiana and northwestern Ohio as the Maumee River outlet developed by capturing streams that formerly drained into the Wabash. The Great Black Swamp that once occupied much of the land between Sandusky, Ohio, and New Haven, Indiana, was a remnant of the bed of Glacial Lake Maumee. Geologists call the former lake bottom the Maumee Lacustrine Plain.
Highest Beach
The altitude of the highest Maumee beach is at the head of the outlet in the vicinity of Fort Wayne and New Haven, Ind. To the northeast,, along the Ohio and Michigan state line, it is higher. In West Unity and Fayette, Ohio, the beach is at. The strong beach is generally above and at a few points rises to. On the south side of Lake Maumee the highest beach from Fort Wayne to Cleveland. The maps show it to be from Delphos to Findlay.
