shaft. But inasmuch as the surface of the ground rises rapidly to the south, while the beds fall, that rise being at least 100 feet in the 450 yards, we get over the head of the gate-road a thickness of beds above the Thick coal of not less than 977 feet.[1] Let us, then, suppose the beds to be absolutely horizontal from the end of the gate-road to Hasbury Hill, south-west of Halesowen, which those near the surface certainly are for the greater part of the distance, we must still add another 70 feet for the total rise of ground from Hawn to Highfields. Hasbury,[2] when we shall have a thickness of at least 1,000 feet between the uppermost beds seen there and the top of the Thick coal.
The details of the beds passed through in the Hawn shaft are not known, but the high ground on all sides of it is composed of greenish brown sandstone, dipping generally at a very gentle angle to the south. In the lane leading from Hawn to Gosty Hill, these sandstones are conglomeritic, and many of the pebbles consist of fragments of trap, not, however, of basalt or greenstone, but of brown and purple porphyry (or felstone) very like some of those so abundant in the Permian rocks of the Clent Hills. It appears, therefore, that fragments of such rocks began to be drifted from some rather distant locality even during the Coal-measure period.
These beds and those quarried near Halesowen are probably below the sandstones of Luticy and Wassel Grove, in which the little beds of coal before mentioned occur, for the places where these coals occur are both further south and on higher ground than that round Hawn and Halesowen.
Mr. G. Thompson, formerly manager of the British Iron Company's Works at Corngreaves, communicated the following section of the pit sunk at Wassel Grove.
| FT. | IN. | ||
| 1. | Sand rock and other rocks | 123 | 0 |
| 2. | Blue rock-binds | 4 | 0 |
| 3. | Sand rock | 38 | 0 |
| 4. | Little coal | 0 | 4 |
| 5. | Blue rock with black shades | 5 | 0 |
| 6. | Grey peldon | 0 | 8 |
| 7. | Rock binds | 2 | 0 |
| 8. | Rough mingled rock | 13 | 0 |
| 9. | Blue rock | 4 | 0 |
| 10. | Fire-clay | 6 | 0 |
| 11. | Soft white rock | 13 | 0 |
| 12. | Bind measures with two ironstone bands | 4 | 0 |
| 13. | Coal | 1 | 6 |
| 14. | Fire-clay | 4 | 0 |
| 15. | White rock | 15 | 0 |
| 16. | Mingled ground with binds | 5 | 0 |
| 17. | Rock with sheds (bored into) | 45 | 0 |
| 283 | 6 | ||
- ↑ To the original 765 feet we must add 112 for the fall of the beds, 100 for the rise of the ground=977 feet: deducting 30 feet for the thickness of the coal, we get in round numbers 950 feet for the thickness above the coal.
- ↑ The Hawn pits are 370 feet above the sea. Captain Ibbetson made the spot at "H" of "High fields" in the Ordnance map 540 feet above the sea; difference = 170 feet.
