materials). This provides a starting point for understanding what role the parent material played during the formation of the soil. The generalized relationships obtained from these studies can be used to determine what effects the parent material had on the paleosol during its formation. The difficulty lies with the fact that the parent material no longer exists, and therefore its nature can only be estimated using nearby materials. These estimates are typically based on four critical assumptions that should be recognized as assumptions, and thus assessed cautiously when evaluating soils and paleosols. The first assumption is that the parent material is fresh. This means that the parent material assumed to be a proxy for the original parent material must be both chemically and physically similar to that original material. For example, saprolite cannot be considered to be an accurate representation of a parent material derived from a forested soil on granite, but could be considered to represent a parent material of a cultivated soil formed after a clear-cut and erosion of a forested soil. The second assumption is that the parent material was uniform. This assumption states that the parent material had a uniform composition within the soil profile. If the properties of the material found below the profile are to be considered representative of the parent material of the entire profile, this must be true. However, this is difficult considering that few rocks or sediments are uniform enough to be considered an accurate representation of the original parent material. For example, it is extremely difficult to detect a thin layer of windblown dust on top of granite within a thick clayey soil. The third assumption is that one constituent is stable. This states that at least one of the constituents of the parent material is unaltered by weathering and is still present. The main problem with this is that no constituents are fully immune to the breadth weathering processes that exist in nature (Gardner 1980). For example, quartz is a fairly stable mineral in soils with pH>9, where alumina (AlO) is stable in between pH 4.5 and 8 (mostly in clay). Trace elements that are usually stable in soils over a wider range of environmental conditions include lead (Pb) and zirconium (Zr), but are not always sufficiently present to be useful. The fourth assumption is that volume change is proportional to thickness and density. This states that the loss