THE PERMIAN FORMATION. !)!) 



at once becomes apparent, the magnesian limestouo gradually over- 

 lapping the coal measure strata in succession, until at length it comes to 

 repose directly on millstone grit. Through the intervening millstoue grit 

 country run many anticlinals approximately east and west, which pass 

 under undisturbed magnesian limestone. Several large faults do the 

 same. In the coal measure districts, too, we find that even where the 

 strike is the same there is still a more or less perceptible difference 

 in dip between the carboniferous and the Permian strata. Tbis is 

 sometimes shewn in open cuttings, and is inferred from the increased 

 depths at which particular coal seams are found beneath the base of the 

 Permian rocks, as we go east from the vicinity of the magnesian 

 limestone escarpment in Yorkshire, and north-east from the southern 

 margin of the limestone area in Durham. 



The above facts clearly show tbat, before the commencement of 

 the Permian epoch, the carboniferous and older palaeozoic rocks of the 

 north of England had been subjected to powerful earth movements 

 both along the north and south and east and west axes of upheaval, 

 followed by long continued and extensive denudation. It was then 

 tbat the Peunine chain, that range of high ground which stretches 

 from mid-Derbyshire to the borders of Scotland, was elevated, and 

 afterwards so deeply denuded, that rocks as low down in the series 

 as mountain limestone were laid bare in the heart of the chain, (a) 

 See Plate VI. 



Before proceeding to describe the Permian rocks of the north-east 

 of England, I shall, in the first place, notice a rock (or rather a structure 

 assumed at times by very various rocks) that was formerly classed with 

 the Permians, but is now pretty generally understood to belong to the 

 carboniferous system. 



Lower Red Sandstone or Rothliegende : — Carboniferous Rocks. 

 Beneath the magnesian limestone, along its western escarpment, 

 are a number of beds of incoherent yellow sand and beds of sandstone 

 and shale, which in many cases are coloured of a deep red by oxide of 

 iron. Such, for instance, are the extensive beds of yellow sand and 

 red sandstone, so frequently found skirting the magnesian limestone 

 escarpment in Durham ; and the Plumpton sandstone or Knaresboro' 

 grit, and the Rotherham red rock in Yorkshire. These beds were 

 originally classed by Drs. Smith and Sedgwick as " lower red sand- 

 stone " — the Rothliegende of Murchison. Later researches, however, 

 by several accurate observers, such as Messrs. Howse, Binney, Ward, 

 Lucas, (b) and others, have made it clear that these rocks belong, not 



(a) The Age of the Pennine Chain. E. Wilson, F.G.S., Geol. Wag., vol. vi., 

 p. 500. (Brit. Ass.) Midland Naturalist, vol. iii., pt. 1. 1880. 



lb) On the so-called Lower Red Sandstone of Central Yorkshire, by E. \V. 

 Binney, F.R.S., F.G.S. Geol. Mag., vol. iii., 18GG. p. 49. On beds of Sup. 

 Rothliegende Age near Knaresboro', &c, by J. C. Ward. F.G.S., Q.J.G.S.. vol. \xv.. 

 p. 291. On the Permian Beds of Yorkshire, by Joseph Lucas. F.G.S. Geol. Mag., 

 1872, p. 338. Notes on the Permian System of Durham and Northumberland, R. 

 Howse, 1848. West Yorkshire, by Davis and Lees, 1878, p. 170. Geology of the 

 Yorkshire Coldtield. Mem : Geol. Survey, 1878, p. 481. Geology of parts of Notts, 

 Yorkshire, and Derbyshire, bv W. T. Aveline. Mem. Geol. Survey, -2nd Ed., 1880, 

 1>. 12. 



