Oneida Twin Ridges

Steven Dutch, Professor Emeritus, Natural and Applied Sciences, University of Wisconsin - Green Bay

---

A puzzling pair of ridges parallel Duck Creek northeast of the town of Oneida. Highway 54 runs along the crest of the eastern ridge for a short distance. Note the tapering, rather drumlin-like shape of the eastern ridge.

Below is a colored elevation map of the area

These ridges were called "eskers" by F.T. Thwaites, although Thwaites stated that he used the term "esker" to denote any ridge of glacial deposits. In a sketch map of the ridges, he labeled them "overridden eskers or crevasse fills." They are certainly not eskers in the strict sense and very unlikely to be crevasse fills. The eastern ridge seems to be a very elongate drumlin-like feature, and is parallel to several other similar ridges in the Green Bay area. Not far northeast along Highway 29 are some much clearer drumlins. The original nature of the ridge before being streamlined by the ice is unknown. It seems very wide for an esker although a tunnel-fill deposit is possible.

In contrast to the eastern ridge, the origin of the western ridge is pretty clear-cut. Note the steep eastern front, the gentle western slope, and the very flat terrain west of the ridge. Also note that the flat terrain west of the ridge is much higher than the valley of Duck Creek. It is probably a former ice front, where glacial lake deposits topped by low moraines and alluvial fans were banked against the ice.

The Eastern Ridge

	A view northwest toward the western ridge. Duck Creek is marked by the tree line in the valley.
	A view southeast toward dissected glacial deposits on the western edge of the city of Green Bay.

The Western Ridge

	A view of the ridge looking southeast from County U just north of Oneida. The ridge is a slight raised rim on the edge of a flat upland. The most likely explanation is that the ridge marks a former ice front. The raised lip is made of moraine and alluvial fan deposits and the flat land beyond is underlain by glacial lake deposits.
	A view in the opposite direction looking at the glacial lake plain. With ice to the east, the lake deposits stopped at the ice front. When the ice melted, the edge of the lake deposits was left behind as a steep slope.
	A view southeast looking across the valley of Duck Creek toward the eastern ridge. The road slanting down the left side of the eastern ridge is Highway 54.
	A view from St. Joseph's Church in Oneida looking down the gentle western slope of the ridge to the flat glacial lake plain beyond.
	A view east along Highway 54 between Oneida and Seymour showing the extremely flat glacial lake plain. This lake plain is probably older than that of Glacial Lake Oshkosh and is mantled by a slightly irregular thin blanket of till.

---

Return to Geology of Wisconsin Index
Return to Geologic Localities Index
Return to Professor Dutch's Home Page

Created 2 August 1999, Last Update 11 January 2020