I have already said that the New Red Marl of England is more closely related physically to the Rhaetic and, in some respects, to the Liassic beds, than to the Bunter strata ; and I will now state the stratigraphical phenomena that have led me to form this opinion.
South and south-west of the Mendip Hills, the New Red Marl and the Magnesian Conglomerates at its base lie directly on Carboniferous strata. The Rhaetic beds and Lower Lias immediately succeed these, the former lying conformably on, and generally passing into the Red Marl by obvious gradations. On the north, between the Mendip Hills and Tortworth, the Keuper Marls and sandstones, with occasional Magnesian Conglomerates, also he on Carboniferous strata. North of Tortworth, as far as the Severn, the Marl, very thin and without any Lower Keuper Sandstone, lies directly on Silurian strata ; and on the north side of the estuary it lies indifferently on Old Red Sandstone and Carboniferous rocks. Everywhere in these districts it is immediately succeeded by Rhaetic beds, which graduate downwards lithologically into the Marls ; and these Rhaetic beds are invariably followed by true Lower Lias. The same is the case north and north-west of Gloucester, where the Keuper beds lie on Old Red Sandstone ; and on the east of this area the upper Marls still pass into Rhaetic beds regularly overlain by Lias Clay. It is not till we come towards the south end of the Malvern range, that Bunter Sandstones appear beneath the Marl. On the east side of the Malvern and Abberley range, the Bunter beds are thrown out of sight by a fault ; but further north they come out in full force, extending along the flanks of the Permian strata that bound the Forest of Wyre, the Coalbrook Dale country, and the South Staffordshire Coal-field, whence they stretch along the eastern limits of North Wales, to the estuary of the Dee and the Mersey. Thence the full Bunter series skirts the Lancashire, Cheshire, and North Staffordshire Coal-fields, lying frequently on Permian rocks, then passing eastward by Ashbourne towards Nottingham, and along the flank of the Magnesian Limestone northward into Yorkshire *.
East of South Staffordshire the case is different. Round the "Warwickshire Coal-field, the Keuper strata, where unfaulted, he directly either on Permian or Carboniferous beds, with one small exception north of Atherstone, where Bunter pebble-beds appear for about a mile. Some very thin Bunter beds appear on and round the flanks of the Leicestershire Coal-field ; but generally the Lower Keuper Sandstones lie directly upon Coal-measures; while further east, round Charnwood Forest, the marl lies directly on Cambrian rocks ; and the same is the case with respect to the igneous bosses that rise through the marl further south.
Wherever the New Red Marl seems to attain its complete thickness, it passes into Rhaetic strata ; and these are always succeeded by Lower Lias, as far as the Rhaetic beds have yet been observed. Obser-
- Sometimes the Bunter beds are cut out by faults for a space ; but this does
not affect the general question.
