The physiography of southwest Michigan is characteristic of a mature glacial outwash plain and moraine complex. This ice mass was met by the Huron-Saginaw lobe that extended southeastward through the present Saginaw Bay and across the Lower Peninsula of Michigan. These glacial lobes caused great disturbance of the surface topography and upon retreat left a complex landscape of highly heterogeneous deposits. The result was a diverse depressional pattern of many kettle lakes interspersed among steeply undulating hills and outwash channels. Dominant surface features are overlain with glacial outwash of mainly sand and gravel.
Most soils are sandy loam and silty clay loams of moderate fertility.
These pedons represent the most commonly described soil properties and are well established and recognized by the National Cooperative Soil Survey. Histosols and Mollisols are found exclusively in wet depressional areas characterized by poor drainage and the accumulation of organic matter. Entisols occur along drainages where the stratification of coarse sandy subsurface horizons reflects the deposition of sediments under changing currents and shifting channels during flooding. These soils occupy nearly level to rolling slopes. The Kalamazoo series consists of well drained soils that are moderately permeable in the upper part of the profile and rapidly permeable in the lower part.