LOWER COAL AND IRONSTONE MEASURES. 



473 



each averaging about 6 feet in thickness, and about 15 feet beneath them is the 4 foot bed of ce- 

 lebrated fire clay. 



A good natural outcrop of the coal measures is seen on the eastern side of the Hayes. This has 

 been already alluded to, in treating of the Lower New Red Sandstone, and will be again adverted to 

 in describing the Silurian rocks which there cut out the coal. But the best of all the natural 

 outcrops of the lower coal beds which fell under my notice occurs near Ettingshall. The strata 

 there rise at angles of 30° and 35° from under the thick coal of Bilston, and appear successively 

 at the surface, on the side of the south-eastern end of the Silurian rocks of Hurst Hill, particularly 

 near the Coppice Meeting-house, as represented PI. 37. f- 4. 



Three seams of coal are worked, and called the top, new mine, and bottom, with two courses of 

 fire clay, the lower of which lying beneath the bottom coal, as at Stourbridge, is considered the 

 most valuable. These lower measures are overlaid by a ferruginous grit and thick-bedded sand- 

 stone (a good millstone grit) containing many impressions of plants. 



Four sections, furnished me by Mr. Downing, of the lower coal measures and ironstone, are an- 

 nexed (table, p. 478.), and as these are taken from shafts sunk near the northern end of the 10 yard 

 field, they are valuable accompaniments to those furnished from its southern end by Mr. Best, p. 477- 

 From these it will be seen, that as the field ranges to the north, the underlying measures become 

 more impregnated with iron, and in the Bilston Meadow pit we already perceive seven courses of 

 iron ore, of which five are of good quality. 



. The structure of the northern end of these coal tracts has been well ascertained in the 

 neighbourhood of Wolverhampton, and also between that place and Wallsall, where 

 the ironstone measures approaching the surface have been very largely worked. 



The first of the sections, p. 479, is that of the shafts at the Willington Colliery, 

 near Wolverhampton 1 , and may serve as a good type of the most valuable ironstone 

 measures known in that district. 



The other sections on the same page relate to various parts of the northern field 

 near its eastern limits. See table, p. 480. 



By comparing the section of the strata near Wolverhampton, p. 479, with those 

 given (p. 478.) in the neighbourhood of Bilston, we see how materially the strata of the 

 same age have changed their characters and dimensions in about two miles. Near 

 Bilston, the heathen coal is separated from the new mine coal by 37J yards of inter- 

 vening measures. At Willington, near Wolverhampton, these seams are 51 yards apart, 

 some of the intermediate beds having greatly expanded, while others have dwindled 

 away; the new mine coal, for example, which is about 4 yards thick near Bilston, having 

 become little more than 2 at the Willington Colliery. 



In like manner, although the last-mentioned section affords an average sample of the 

 coal strata near Wolverhampton, it does not apply to the area north or west of that 

 place. Thus, the section through the whole of the coal measures at the Rough Hills, 

 north of Rushall and Daw End, differs very materially, while at the Birch Hill Col- 



1 Supplied by Mr. W. Barker. 



