Organic wetlands soils are those that, within at least 1.5 feet of the surface, are made mostly of the remains of plants and animals. Wet organic soils look like black much or black to dark brown peat. Where there is little or no organic material, the soil is classified as mineral soil. Mineral soils can be made of a wide range of materials, such as sand, silt, clay, or loam. Gleyed soils are neutral gray or greenish or bluish gray.
Mottled soils are mostly gray, but contain splotches of brown, orange, red, or yellow.
Some soils contain manganese, which forms black spots in waterlogged conditions. When you dig a hole to study wetland soil, you may find horizontal layers of different soils. The soil types that you find will depend upon the area. The makeup of the soil in an area may have been changed by human activity, such as tilling for agriculture or draining or filling for development. If you are looking at soil in a city, a suburban housing community, or near farmland, you may have to dig deeper to find hydric soil.