Near Gwinn, there are many kettle lakes and depressions, some containing ponds and bog vegetation. Farther to the south, the outwash slopes gradually to the southeast. The Escanaba River flows through the wetland. The southern part of the sub-subsection has thick, acidic, organic soils over sand or sandy loam. The northern part has excessively drained sand soils.
Bedrock is exposed at the margins of the outwash plain in the west.
The extensive conifer swamps contained abundant northern white-cedar at the upland margins, with increased amounts of black spruce and tamarack dominant in the wetland interior. Swamp hardwoods included balsam poplar, red maple, paper birch, and black ash. The excessively drained outwash supported open stands of jack pine. White pine and red pine, along with some northern hardwoods, were located on steeply sloping channels on the outwash. White pine and hemlock stands were locally dominant on the margins of kettle lakes.