had subsequently suffered an almost equal amount of destruction, and another great cliff formed; and that in some places the whole of the Permian formation had been utterly removed, and the old Coal-measure cliff re-exposed, only to be again concealed and the second gap filled up by subsequently-formed beds of New red sandstone. Such a recurrence of so singular a phenomenon was too much for the wildest hypothesis to affirm; and we shall. I think, see reason to conclude that the east and west boundaries of the coal-field are not only genuine faults, clean-cut fractures, but that they were produced late in the New red sandstone period, if not subsequently to it altogether.
The practical bearing of this discussion will be at once seen, if we reflect that on the first supposition of the boundaries being cliffs, a very large part of the Coal-measures, with their accompanying wealth of coal and iron, must have been removed from the spaces between our present coal-fields; if, on the other hand, the boundaries are faults, we have still all or the greater part of the Coal-measures concealed and untouched under the New red sandstone of the great central plain of England.
We will now examine a little in detail these two boundary faults, commencing with the eastern one near its southern extremity on the Birmingham and Halesowen road.
The Eastern Boundary fault.—At Perry Hill the angular trappean breccia of the Permian rocks is seen in the cutting of the road, the Red rock extending up to the turnpike. Near the Hagge, Round Hill, and "Barn," yellow Coal-measure sandstone may be seen. Just where "ra" of "Brand Hall" is in the map is an old quarry in the calcareous conglomerate, described before as occurring in the Permian rocks. This band of calcarcous conglomerate can be traced thence to Barnford Hill, where it is much farther from the fault than it was at Brand Hall. This looks as if the fault increased in amount as it ran south, concealing more and more of the Permian rocks, and thus bringing this conglomerate bed nearer and nearer to it.
About 350 yards south-west of Langley mill there is an old pit only 130 yards (390 feet) deep, which, from the quantity of Silurian shale full of fossils on the bank, must have had almost the whole of its lower half altogether in that formation.[1] This is very near the boundary fault, but how the Silurian shale comes to be so near to the surface as even 100 yards is not easy to explain. From some old mining plans of this locality lent to me by Mr. S. H. Blackwell there appeared to have been here a curious complication of faults, the clue to which I did not succeed in unravelling. A little north of this, in Mr. Chance's pits, the Thick coal thinned out to 7 feet as it approached the fault. Red rock can be seen at the surface very near the line of the fault as it is drawn on the map. It is probable, then, that there is here a complication similar to that described before in Lord Dartmouth's Heath pits at West Bromwich.[2]
- ↑ It is a curious instance of the frequent want of the commonest knowledge in this district, that an intelligent man who acted often as a "ground bailiff" in the neighbourhood, his father and brother being both of that profession, was yet not aware that it was impossible to find coal beneath shale containing Silurian fossils.
- ↑ A dotted line was drawn on the map to call attention to the probable connexion between these two places. This connexion subsequent workings near Spon Lane have proved not to exist on the Thick coal level all the way, at all events not to run along the exact line drawn in the map, though it may run a little farther east of it.
