thickening in those upper measures is only a still further carrying out of a structure or character common to the whole coal-field.
Connexion of the Wyrley and Essington district with the rest of the Coal-field.—_We have now given a detailed description of the beds constituting the Coal-measures of the central and southern portion of the field, and have traced the lower beds in detail as far north as the Brown Hills.
The Heathen and Sulphur coals were also traced in detail up to the neighbourhood of Bloxwich, and have been mentioned as forming the uppermost measure in some of the more western pits in the Brown Hills district.
The dip of the beds from Bentley to Bloxwich, and from Bloxwich all over the Pelsall and Brown Hills district is from east to west, at a low but steady angle of inclination. The dip of the beds at Essington and Wyrley is likewise from east to west at the same gentle angle. It follows that unless there be a great fault or a great flexure running north and south between Pelsall and Essington on the one side, and the Brown Hills and Wyrley on the other, that the beds which are worked along the eastern side of this portion of the field dip under those that are worked on the western side, and would be found underneath them if a sufficiently deep sinking were made.
Two such explorations have been made, as will be seen presently, one 8 boring and the other a shaft, and though not quite conclusive in their results, are yet in favour of that belief as far as they go.
Neither from Bentley nor from Pelsall have there been any continuous workings up to Essington and Wyrley, a width of a mile and a half or two miles of unexplored ground isolating the Essington and Wyrley collieries from the rest of the coal-field. It is believed, from some sinkings that were made formerly near the New Invention, and from other appearances, that this belt of unexplored ground is greatly cut up by sheets and masses of trap rock. We are accordingly left to the following evidence in order to connect the Essington and Wyrley beds with the other beds of the coal-field, and prove the statement made in the General Description (Chapter V.), that the coals there represent the Thick coals.
We have seen that the Bottom coal and the beds immediately above it are worked continuously from the neighbourhood of Bilston and Wolverhampton under the Bentley and Bloxwich districts, up to Pelsall and the Brown Hills; and that as they range from the former towards the latter, the measures increase in thickness, and beds which lie together in the southern part are, as they run north, split up by intervening measures and sometimes widely separated from each other. It will be remembered also that between Bilston and Wolverhampton the Thick coal has already lost the two upper beds, which have gone off as the Flying reed, and cropped out south of the Lanesfield fault, and that the remaining part is also separated into two masses by an intervening bed of shale 10 feet thick, called "Hob and Jack."
The measures rise from this district gently towards the north, the Thick coal cropping out directly, and the beds below it gradually and successively until at Bentley Hall and Deepmore Coppice the Bottom coal is but a little way below the surface of the ground.
A little north of Deepmore coppice a great fault running nearly east and west throws down the measures to the north to the extent of 360 feet so that the Bottom coal is then about 400 feet deep, with all the measures above it easily recognizable up to the Heathen coal, which is there about 144 feet deep. Now, as the Heathen coal about Bilston is never more than some 30 feet below the Thick coal, it follows that we
