In geology, bedrock is solid rock that lies under loose material (regolith) within the crust of Earth or another terrestrial planet.
For my own part, I should doubtless have belonged to the latter class, had I received instruction from but one master, or had I never known the diversities of opinion that from time immemorial have prevailed among men of the greatest learning.
The various kinds of broken and weathered rock material, such as soil and subsoil, that may overlie the bedrock are known as regolith.