It appears certain that the coals which crop about the Brown Hills, and are known to be cut off by a fault there running north-north-east and south-sonth-west from Watling Street to the canal a little east of Birch Coppice, are thrown down under Clayhanger to a depth of more than 1,000 feet (300 or 400 yards), and that they lie at that depth under all Walsall Wood, forming the bottom part of the Coal-measures from which coals are now being got at the Coppy Hall colliery at Stubbock's Green, and that were proved to exist at the Aldridge Trial pits a little north of Red House.
It seems also certain that the Clayhanger fault must continue somewhere down by Goblins Pit Wood and Shelfield, towards Coal Heath, with a downthrow to the east.
It seems also quite certain that the abrupt northern termination of the limestones of Daw End and Hay Head along a certain line, with the equally abrupt coming in of Coal-measures immediately north of that line is the result of a fault having a downthrow to the north-east, and it is very probable then that the two faults thus proved to have a similar large downthrow, are in reality one fault, forming a branch of the boundary fault. If this be so the eastern boundary fault will form two step-like eastern downthrows from the Brown Hills to Hill End, south of Aldridge, while south of that it again becomes only one downthrow, but not of so large an amount, so that it allows the Permian rocks to appear at the surface on its eastern or downthrow side, instead of bringing down the New red sandstone to the level of that surface.
The Western Boundary fault—If we begin on the south, we may say that the western boundary fault of the coal-field commences at the northern slope of Wychbury Hill. Thence to Oldswinford we have the Brick red sandstone and conglomerates on one side, and the upper Coal-measures on the other side of the fault. North of Oldswinford we get the Thick coal on the upcast side of the fault, cropping up against it and into it at an angle of 45° west of the "Grange," and on the downcast side we get a narrow band of Permian, soon overlaid by the base of the New red sandstone.
By Penn's Hill and Dennis to Audenham Bank, the beds below the Thick coal crop on the east of the fault, the Thick coal ranging up to it a little south of Brettell Lane, while the red rocks may be frequently seen at the surface just westward of the line drawn on the map.
Near Wordesley the New red sandstone dips at an angle of 20° to the west; the Permian, therefore, must here dip, at least, at as great an angle from the fault. At Bug Pool they sank through the fault down into the Thick coal below in consequence of the great overhanging ("bade," "overlie," "underlie," "inclination,") of the fault. In these pits they had 40 yards of "red rock," and got the Thick coal at 126 yards from the surface. Between Wordesley and Salters Hill. Mr. Bond sank 280 yards (840 fect) in the Permian rock at about 200 yards from its surface boundary, without passing through it into the Coal-measures. At the New Bromley Lane colliery south of the Stand Hills. Messrs. Davis have recently passed through the overhanging fault into the Coal-measures at a depth of 142 feet.
The junctions of the great faults called the Brockmoor. Corbyn's Hall, and Shut End faults with the Boundary fault (or perhaps we should say the separation of these great branches from it) appear to have little or no effect on its character. At Kingswinford the Brick red sandstone of the New red formation comes up against the fault, and we have that sandstone on the one side and the Coal-measures, with the Thick coal 140 yards (420 feet) deep, on the other. Before reaching Himley Park the boundary fault seems to split and let in
