feet, and even less.[1] Again, at Birchy-field colliery, between Portway Hall and Titford reservoir, the Thick coal is only 21 feet thick, the whole number of beds being described as present, but each a little thinner than ordinary; and further south, near Titford reservoir, the Thick coal was said to end altogether, either by gradual thinning or by the interposition of sandstone and shale beds.
At the time when the first edition of this Memoir was published the above was all the intelligence that could be procured as to the south-eastern corner of the coal-field. Several subsequent explorations, however, have been made which I was able partially to examine in 1858.
In the first place. Dr. Percy's workings in the Thick coal at the Grace Mary collicry, on the north slope of the Rowley Hills, near Lye Cross Farm, have been continued towards the south, or towards the ground where the basalt appears at the surface. The Thick coal in that direction was greatly deteriorated, and its value almost altogether destroyed, by two circumstances, first by its place being largely occupied by white sandstone, which was deposited together with it; secondly, by veins of trap having been subsequently intruded into it. The sandstone thus contemporaneously deposited with the Thick coal, or instead of it, is spoken of sometimes as "rock and rig," and sometimes as a "rock fault." It will be presently described under the latter designation. The trap veins will be also described under the head of Igneous rocks.
In the colliery belonging to Messrs. Bagnall, adjacent to Dr. Percy's, similar or even greater deterioration of the Thick coal was said to occur.
In the district south of Portway Hall some pits have recently been sunk for Lord Ward. One of these is at Ramrod Hall, a little east of Rowley Regis, just where the W. of "White Heath Gate" is engraved on the Ordnance map. In this pit the following section was found, as communicated by Mr. Spence:—
| FT. | IN. | ||
| [2]1. | Binds, marl, rock, &c. | 381 | 0 |
| 2. | Coal (Two-foot?) | 1 | 9 |
| 3. | Black ground and fire-clay | 10 | 3 |
| 4. | Brooch coal and batt | 1 | 0 |
| 5. | Blue binds and sand rocks | 124 | 0 |
| 6. | Broad earth | 3 | 0 |
| 7. | Black batt | 1 | 0 |
| 8. | Thick coal (mingled with sandstones) | 4 | 0 |
| 9. | Gubbin measures and Heathen coal mixed with sandstone) | 5 | 0 |
| 10. | Rock and rock binds | 16 | 9 |
| 11. | White ironstone measures | 2 | 0 |
| 12. | Binds with a Stinking coal | 5 | 9 |
| 555 | 6 | ||
At a distance of 70 yards to the eastward of this shaft the Thick coal was found instead of 4 feet to be 26 feet thick, but "to contain several layers of thin rock."
