Netherend near Cradley on the other side of the south-western district; nor do I find them mentioned by name in the sections about Highfields and Bradley south of Bilston, nor in those of Great Bridge and the Swan towards West Bromwich. In some sections, however, as in the old one of Bradley mine, beds containing ironstone are mentioned as occurring a short distance below the Brooch coal, which are probably these measures.
10. Intermediate measures, containing the Thick-coal rock.—These measures, according to the details given in thirty-five pit sections, vary greatly, not only in widely separated parts of the coal-field, but often in places immediately adjacent to each other.
In part of the country just south of Bilston the question is complicated by the occurrence of the "Flying reed," which will be described presently. Supposing this Flying reed to be the top beds of the Thick coal, we have here only 90 feet between it and the Brooch, occupied entirely by "blue binds," while in the beds interposed between the Flying reed and the remainder of the Thick coal there occurs a rock or sandstone of considerable thickness. In the district east of Kingswinford, where the phenomenon of the Flying reed again occurs, we have the recurrence of similar facts.
Setting those exceptional cases aside, we have at Bradley about 60 feet of beds between the Brooch and Thick coals, of which the uppermost portion is clunch and rock binds, with ironstone, the lower, peldon and grey rock, 27 feet thick; while around Tipton, Burnt-tree, Tividale, Great Bridge, Oldbury, and West Bromwich, there is an average thickness of between 120 and 130 feet for these beds, the greatest thickness being 170 feet and the least 83 feet. Of this thickness 73 feet on an average is composed of "rock" or sandstone, the greatest amount of that material being 120 feet and the least not more than 20 feet. The method of its occurrence varies as much as its amount, as it is interstratificd with more or less argillaccous materials in every possible way, except that the sandstone seems most generally to preponderate in the lower part of the mass.
In the south-western portion of the district the thickness of these beds also varies considerably. In the mines around Pensnett, Corbyns Hall, and Shut End, their total thickness varies from[1] 52 feet to 116 feet, the average being 85 feet. In those around Corngreaves (or between the Lye Waste and Rowley Regis) the least thickness is 103 feet, the average rising to 125 feet, while the greatest I know is 157 feet. Around Brierley Hill, on the contrary, and at Wordesley Bank and the Black Delph, the greatest thickness of these beds is diminished to 52 feet, they are sometimes as little as 38 feet, the mean being only 46 feet. In each of these cases the thickness seems to vary almost directly as the quantity of "rock" or sandstone. In the Congreaves district the whole of these beds are almost entirely composed of rock and rock binds. Around Brierley Hill there is not more than 6 feet to 12 feet of rock, while round Corbyns Hall the quantity of rock is generally about half the whole mass, being more or less interstratified with beds of binds or clunch, which are generally described as "strong," meaning that the argillaceous is largely mingled with arenaceous or siliceous material. I do not know that any of these beds have acquired distinctive names, except that occasionally I have found near the bottom of them mention made of "Shooter's four measures," or "«Shooter's greys."
- ↑ Still exclusive of those mines in which the Flying reed occurs, when the thickness sometimes diminishes to 29 feet.
