| the layer of disintegrated and decomposed rock fragments, including soil, just above the solid rock of the earth's crust; regolith. |
| mantle rock n. See regolith. |
reg·o·lith  (rěg'ə-lĭth')  n. The layer of loose rock resting on bedrock, constituting the surface of most land. Also called mantle rock. [Greek rhēgos, blanket + -lith.] |