Bedrock

In geology, bedrock is solid rock that lies under loose material (regolith) within the crust of Earth or another terrestrial planet.

[2] The various kinds of broken and weathered rock material, such as soil and subsoil, that may overlie the bedrock are known as regolith.

[7] Exposed bedrock experiences weathering, which may be physical or chemical, and which alters the structure of the rock to leave it susceptible to erosion.

Bedrock may also experience subsurface weathering at its upper boundary, forming saprolite.

[8] A geologic map of an area will usually show the distribution of differing bedrock types, rock that would be exposed at the surface if all soil or other superficial deposits were removed.