The Earth is roughly a sphere. The Earth is an irregularly shaped ellipsoid.
Subsoil: This layer has normally less organic matter than the A horizon, so its colour is mainly derived from iron oxides. Iron oxides and clay minerals accumulate as a result of weathering. In a soil, where substances move down from the topsoil, this is the layer, where they accumulate.
Note: This information has been taken out of a website.
It is called surface currents.
