Beach ridges are not well defined. There is a ground moraine along the northern and southern borders of Glacial Lake Upham. Low drumlin ridges. are present locally. There is also Cretaceous shale, sandstone, and clay near the southwest end of the basin and along the border with the Mesabi Range. Other soil orders present are entisols and alfisols.
Alluvial soils are present along major rivers.
The growing season is short, from 92 to 115 day, as the lowlying subsection forms a frost pocket with late spring frosts and early fall frosts. Several major rivers flow through this subsection. These include the Mississippi, the St. Louis, the Whiteface, the East Swan, the Savannah, and the Willow Rivers. Rivers and streams meander extensively across the subsection due to the predominately level landscape. There are few lakes present in the lake plain.