Organic soils in the kettle bogs can be several feet thick. Oak savanna, also dominated by white oak, with some black oak, occurred on some south and west aspect slopes and on some of the more gently sloping ridges. Kettle depressions supported hardwood swamps, tamarack swamps, shrub swamps, and bog. Although many of the steep lands were either cleared for crops or grazed by livestock, many of the farms have failed. Residential developments are expanding from nearby urban areas.
Prairie fens are common along the margins of the sub-subsection.
Oak savanna has converted to oak forest, but may yet be restorable. White oak-white pine savanna and forest, once quite common, persist locally. These forested areas also function as important migration corridors for song birds.