Type area designated in secs 4-9, T136N, R73W, Logan Co, ND, 10 mi southeast of Long Lake, for which unit is named, Williston basin. Long Lake extends northwest into Emmons, Kidder, and Burleigh Cos. Drifts described in this report are not lithostratigraphic units as defined by American Commission on Stratigraphic Nomenclature (1961) because drifts have been differentiated by their topographic form, geographic position, and inferred geologic history. Consists of till of Long Lake end moraine plus other associated drift that originated from same glacial ice. Lithology of the four Wisconsin drifts in study area are nearly identical; most of till is light olive gray and contains about equal amounts of clay, silt, and sand and about 5% pebbles, cobbles, and boulders. Long Lake is distinguished from older Napoleon Drift (new) by its lack of drainage integration; younger than Zeeland Drift (new). Geologic map; correlation chart. Assigned late Wisconsin (Pleistocene) age though actual age is unknown.

Source: GNU records (USGS DDS-6; Denver GNULEX).