Soil is at the foundation, literally, of the landscape. It is the interface between the non-living minerals contained in bedrock and surficial geology and the plants and animals living above ground. The process of developing soil is a slow one, with the non-living bedrock and surficial deposits contributing to the mix as they are broken down by water and tree roots and the resulting minerals are incorporated. At the same time, plants, animals and fungi above the soil surface contribute organic material to the soil and affect the rates at which the materials are cycled.
The soils of the Prosper Valley, therefore, have in common that they are derived from the rock of the Waits River Formation, and of the glacial till and other sand and gravel deposits that the glaciers left. The mineral mica – the shiny flecks - seen in both the till and the bedrock can be seen in the soils. Outside of this common parent materials, the soils vary in different ways. In some places, such as in the headwaters in the gulf region or in the fertile valley bottom, the soils are more enriched than in other places, either from pockets of enriched bedrock or from colluvium – the accumulation of minerals in the flow of water. In some areas, the soils are wetter, such as in the wetlands of Bridgewater. These different variances in the soil in turn cause a variety of plants and animals to occur in different places throughout the Valley.