The source of the weathered mineral matter from which soils develop is called the parent material, and it is a major factor influencing a newly forming soil. Gradually it undergoes physical and chemical changes as the processes of soil formation progress. Parent material may be the underlying bedrock, or it can be a layer ofunconsolidated deposits, as in a stream valley. When the parent material is bedrock, the soils are termed residual soils.By contrast, those developed on unconsolidated sediment are called transported soils(Figure 1.14). Note that transported soils form in place on parent materials that have been carried from elsewhere and deposited by gravity, water, wind, or ice.