If it is present, the top horizon will by the O layer, which is comprised of organic matter (Figure 2). This layer is normally found in forest soils, where dead leaves and other detritus can build up on a yearly basis. Below the O layer will be the A horizon, which is where the organic material is mixed in with the inorganic material. This layer is usually darker in color, and if present, means that the soil will generally be fertile for plant life. In a forest environment, there will sometimes by an E horizon below the A that is a result of water becoming acidic as it passes through the O and A horizons and then leaching minerals out of the soil. Below this horizon if it is present, or below
the A if it is not, is the B layer, which is where the minerals and clay grains accumulate. In some regions, this layer can be very thick and tightly pored, resulting in hardpan that can very effectively impede the flow of water through it. Below the B horizon is the C, which contains the parent inorganic material for the soil. It is little affected from the original soil before it matured.