Rating | Solver | Clue |
---|---|---|
VEIN | Coal stratum | |
SEAM | Coal stratum | |
DAY-COAL | The upper stratum of coal, as nearest the light or surface. | |
BED | A layer or seam, or a horizontal stratum between layers; as, a bed of coal, iron, etc. | |
UNDERCLAY | A stratum of clay lying beneath a coal bed, often containing the roots of coal plants, especially the Stigmaria. |