The nature of the pavement of the coal seam, particularly as to hardness and softness; and if soft, to what depth it may be so.
The coal seam was also visited by different parties of officers.
“Levels,” or slightly ascending passages, driven into the hill sides till they struck the coal seam, appear to have been general.
The whole thickness of the coal seam is exposed along the walls.
A stratum of fire clay commonly underlies a coal seam, and there occur also beds of iron ore.
In making excavations consequent on rebuilding the Hall, a coal seam was discovered, which eventually doubled the family wealth.
I could tell you a dozen more freak things that a coal seam can do.
It is, in fact, a coal seam bearing the clearest possible evidence of its plant nature.
As they made their way along, the under-viewer showed him a fault in the coal seam, and explained what it was.
I want to make out how wide the coal seam is, and whether it would be easy to work.