find a very great resemblance in the thicknesses of the beds immediately
below them, as follows:—
| Aldridge. | Coppy Hall. | Essington. | |||||
|---|---|---|---|---|---|---|---|
| 1. | Small coals and partings | 38 | 6 | 12 | 8 | 12 | 0 |
| Intermediate | 86 | 6 | 92 | 8 | 70 | 5 | |
| 2. | Coal and batt | 3 | 6 | 2 | 3 | 2 | 1 |
| Intermediate | 33 | 7 | 31 | 7 | 32 | 6 | |
| 3. | Coal and partings | 7 | 8 | 7 | 6 | 7 | 6 |
| Intermediate | 36 | 10 | 24 | 0 | 57 | 3 | |
| 4. | Coal and partings | 5 | 10 | 4 | 0 | 5 | 8 |
If the above be anything more than an accidental coincidence, and we may really believe that the measures are the same beds in the three places, it would then follow that, as the fourth or lowest coal just mentioned at Essington is the Old Robins coal, the coal No. 13 of Coppy Hall, and that No. 14 of Aldridge is also the same as the Old Robins coal of Wyrley. Mr. Gilpin, of Wyrley, on the other hand, is of opinion that the ironstones over coal No. 16 of Aldridge and below coal No. 13 of the Coppy Hall section are the same ironstones as those just above the Bottom coal of Wyrley. If that be so, then coal No. 16 of the Aldridge section, p. 100, is the Bottom coal of Wyrley. No. 20 probably the Bentley Hey coal. No. 14 probably the Wyrley Brooch and Benches. No. 10 the Cannel. No. 8 the Charles, and No. 6 the Yard coal. In the Coppy Hall pit then. No. 13 must be the Brooch and Benches. No. 11 the Cannel. No. 9 the Charles. No. 7 the Yard, and No. 5 the Old Robins. If this be so, there is a very wide discrepancy in the thickness of the measures in the two sides of the coal-field, and a still greater one in the thickness between the base of the red clays and the Old Robins coal. If No. 5 of the Coppy Hall pit represent the Old Robins of Essington, we have only about 180 feet between it and the red clays there, while at Essington there is 252 feet without the appearance of any red clays, and they are probably at least 30 or 40 feet higher, perhaps 100 feet. Whatever may be the value of these identifications of particular beds, we may feel pretty sure that the beds at Coppy Hall and the Aldridge trial pits are on about the same geological horizon as the upper coals of Essington and Wyrley, and that all the other Wyrley coals will probably be found eventually below them, as well as the Brown Hills and Pelsall beds at a still lower depth.
If this comparison of the measures on the two sides of the coal-field be right, it follows that as the coal No. 13 of the Coppy Hall colliery lies at a depth of about 280 feet below the base of the red clays there, that is the probable position at which the Old Robins coal may lie below them at Essington Wood, and that as in the pits, of which the section is given at p. 94, "it is 252 feet deep, if that pit had been sunk a little farther on the dip of the beds, the Red coal-measure clays would have appeared in the top of it.
A further consequence of this hypothesis would be that as the place of the Deep coal of Pelsall and the Brown Hills is about 650 feet below the Old Robins coal of Wyrley, it is also about that much under the coal No. 13 of Coppy Hall and No. 14 of Aldridge, and must, therefore, be about 1,200 feet below the surface at Coppy Hall; we should hence get a rough measure for the amount of the fault, which brings in the upper red coal-measure clays of Walsall Wood to the eastward of the outcrop of the Deep coal on Pelsall Heath, for it is obvious that it must have a downthrow to the eastward of consider ably more than 1,000 feet.
It is by no means wished to put forward these statements of figures as absolutely trustworthy or exact, still a fault which brings in those
