Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/40

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18
D. C. DAVIES ON THE UPPER CARBONIFEROUS

the equivalent of the Rotherham Red Rock. From its place below the Magnesian Limestone, as well as from its general resemblance to the rocks of group 2, it should, I think, be placed low down in the Permian strata. As in some of the other sections, this group here contains a thin bed of coal. Group 3 is taken from the sinking at Annesley as described by Mr. Headley[1]. He states that, though not sunk through at Annesley, the lowest stratum of this group is a bed of conglomerate. A quantity of lignite, in the shape of branches of trees, was found in one of the thin limestones. Group 4 consists of red sandstones, which are divided by thin and not continuous beds of red marl.

Section 8 brings us again to the western side of the Pennine chain. I am indebted for it to the kindness of Mr. J. Ward, F.G.S., of Longton. In group 1 we have, as in the Canobie section, a considerable series of Coal-measures above the Spinorbis-limestone, with the difference that, whereas in the Canobie section we have only plant-remains distributed among the shales, here the vegetation has been dense enough to form thin coal-seams. It will be observed that, with these coal-seams, and its other strata, this part of the section corresponds with the same group in the sections of Ardwick, Patricroft, Ifton, and Alberbury; and the whole of these, together with the Canobie section, correspond with the same group in the Nova-Scotia section, no. 20. Groups 2 and 3, are described so minutely that they explain themselves. I may say, however, with reference to the bands of hard grey rock in the red marls of group 3, that probably, had they been examined at the time they were sunk through, they would have been found to be more or less calcareous. They may be taken to represent the limestone bands of the sections on either side.

Section 9 is one well known; it was referred to by Sir R. I. Murchison[2], by whom the limestones were correlated with the calcareous breccia in the same group at Alberbury, section 12. It has since been carefully worked by Mr. Binney, as the leader of the Manchester geologists, as well as by others. Groups 2 and 3 are taken from the sections of Mr. Dickenson[3], F.G.S., H. M. Inspector of Mines, and supplemented by the sections of the Geological Survey. The limestones in group 3 are held by Mr. Binney to be the equivalent of the Magnesian Limestone of the north-eastern counties, with which both they and those of the Patricroft section are connected by a series of sections in the north-western counties. Many of these, which were originally worked out by Mr. Binney, are quoted by Mr. Hull[4]. For the sake of comparison, and in order to show their connexion with each other, as well as the variations which take place in the same groups over a large area, I subjoin the following examples:—

  1. "The Sinking of Annersley Colliery," British-Association Report, 1866, Nottingham meeting, p. 238.
  2. Silurian System, p. 145.
  3. Trans. Manchester Geol. Society, vol. iv. p. 155 et seq.
  4. The Geology of the Country around Wigan. The Geology of the Country around Bolton.