It may not be improper to subjoin here the series of the rock-measures at two or three of the collieries which I visited in the north of Ireland. I shall first give the provincial names, adding the scientific terms which appear to correspond to them.
ROCK-MEASURES OF THE MARY ANN PIT
IN THE COUNTY OF TYRONE,
| from the surface downwards.. | ||||
| provincial terms. | geognostic names | feet. | inch. | |
| 1 | Sandstone | 33 | ||
| 2 | white-metal | Grey-white clay Ironstone | 4 | |
| 3 | Slate | Slate-clay | 2 | |
| 4 | Craw-coal | Slate-coal | 1 | 6 |
| 5 | Turbage | Soft slate-clay | 3 | |
| 6 | Grey-metal | Reddish brown clay iron-st. | 21 | |
| 7 | Slate | Slate-clay | 1 | 6 |
| 8 | Bone-coal | 2 | 4 | |
| 9 | Turbage | as above | 4 | |
| 10 | Grey Bind | 9 | ||
| 11 | Black-measure | like Sand? | 9 | |
| 12 | Grey-metal | 6 | ||
| 13 | Slate | Slate-clay | 2 | |
| 14 | Main Seam of Coal | 5 to 6 | ||
| Total | 104 | 4 | ||
This account of rock-measures falls short of the depth of the pit
itself, by seventy six feet, and we must either suppose that some of
them recur once or twice more in the series, or rather that it is not
perfectly correct: my authorities in this and the following table
were the miners who attended me as guides.
