It happened when the waters of Lake Maumee, possibly in response to an advance of the ice front at the eastern end of the lake, overtopped a "sag" or low spot in the Fort Wayne Moraine, which was a deposit of glacial debris that acted as a natural dam at the site of present-day Fort Wayne, Indiana.
The channel, now a small stream called the Little River, is the largest topographical feature in Allen County, Indiana.
As much as 30 feet of fine sand, silt and organic sediments were deposited in the channel before drainage reversed and was captured by the present-day Maumee River.
The earlier sediments were removed in bulk, leaving only the Sand Point and a few gravel terraces on the valley walls.
The well-developed beach ridges in Ohio and eastern Allen County show a series of lower lake levels.