North of Oldbury the fault is very well traced. At the Flash we have the Thick coal 60 yards (180 feet) deep on one side, and 212 yards (636 feet) on the other, giving a downthrow of 152 yards (456 feet); but the amount of "red rock" sunk through was not known. At Mr. Bennett's pits at Ireland Green the Thick coal is 170 yards (510 feet) deep, while on the other side of the fault, near "the Oaks," it is 288 yards (864 feet), giving a downthrow of 118 yards (354 feet). At the Terrace pits at Christchurch the Thick coal is 252 yards (756 feet) deep, and it was said to be only 45 yards (135 feet) to the bottom of the "red rock," the downthrow of the fault being 88 yards (264 feet). This fault continues to hold its course to the northward for a mile beyond this point, having still a downthrow to the east of 60 or 80 yards (110 to 240 feet), till it appears to be cut off by the Tipton and Hilltop fault. North of the Cross Guns Inn, however, in the Wolverhampton and Birmingham road, it is no longer the boundary of the coal-field even at the surface, as there is no red rock on either side of it. At a new pit sunk about the foot of the "L" of "Lyndon" in the Ordnance map they sank below the Broach coal without meeting with any red rock. From the depth of the Broach here it will be about 200 yards (600 feet) to the Thick coal. About one-third of a mile to the south of this spot is the Lewisham pit, at which the Thick coal is 290 yards (870 feet) deep, and there is said to be 105 yards (315 feet) of red rock above the Coal-measures. It is doubtful whether there be a fault, downcast to the south, between these two points, or whether the lower level of the Thick coal at the Lewisham pits is due merely to the southerly dip of those from Lyndon. A dip of 10° would be sufficient for the purpose. If there be no fault, the Permian red rock must come in either by simple capping of the Coal-measures, or it may have been originally deposited in a sudden hollow of erosion existing formerly in the Coal-measures of that locality. East of Lyndon and north of the "red rock" the Thick coal is said to end at a depth of 200 yards (600 feet) against-a mass of "rock and rig." This is probably an extension of the "rock fault" found both in the "Heath" and "Lewisham" pits as before described.
From this point we have to traverse a district of very great obscurity for two or three miles. A ridge of drift gravel runs from Sandwell park by West Bromwich old church to Charleymount. This drift is in some places 120 feet thick, and effectually screens all the rocks below from observation. At a small public house between Bird End and the Wigmoor station gas escapes from the ground in such quantity that it is used to light the house and the neighbouring cottages. It is almost certain, then, that there are Coal-measures under this spot, though they can only contain the lowest beds of coal. In the cutting of the railway to the north-east of Crank Hall farm Silurian shale full of fossils was found lying horizontally.
In the road going from Wigmoor station to Newtown, red rock may be observed apparently horizontal. "Red rock" spreads from this point over all the country to the north and east. Trusting to these facts, a dotted or supposed fault has been drawn from the Cross Guns to Sunday Bridge. From this point towards the north we have on one side of a certain line running about north-by-east. Silurian shale dipping very slightly to the south; and on the other side, red rock, which, whenever it is exposed, is found to have an easterly dip.
On the Walsall and Birmingham road, as we rise from the Silurian flat about the Bell, on to the gentle elevation on which the Gough's Arms stands, we meet first with some pale wine-coloured mottled calcareous sandstone, above which, in a brick pit, we find some grey
