a. Solid rock exposed at the surface of the Earth or overlain by
unconsolidated material, weathered rock, or soil.
b. In Australia, the stratum upon which the wash dirt rests is usually
called bedrock. It usually consists of granite or boulder clay (glacial)
and, much more rarely, basalt. When the stratum consists of slates or
sandstones (Silurian or Ordovician), it is usually called reef rock.
Eng. Min. J., 1
c. A general term for the rock, usually solid, that underlies soil or
other unconsolidated, superficial material. A British syn. of the
adjectival form is "solid," as in solid geology. See:
d. See: bottom rock; rock base.
Dictionary of Mining, Mineral, and Related Terms