Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/380

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the Magnesian Limestone, and has been formed in quite a different manner. It is a great brecciated conglomerate composed of angular fragments of Carboniferous Limestone, cemented together by carbonate of lime, and as hard and solid as the Carboniferous Limestone itself. In South Staffordshire, North Staffordshire, Shropshire, on the borders of Wales and elsewhere the Permian strata have the same general characters as those of parts of South Staffordshire and Warwickshire, and consist chiefly of red sandstones and marls with occasional brecciated conglomerates, which I have elsewhere described.

I have given this brief sketch of the distribution and lithological characters of the Permian strata of England, simply to remind my readers of their general nature in various areas, and not because I have any occasion to discuss in this paper any questions connected with equivalent geological horizons of Permian age, or of the disturbances that preceded the deposition of the Permian strata and may have helped to rule their characters.

As with the New Red Marl mentioned in a previous paper *, so I consider that the red colouring-matter of the Permian sandstones and marls is due to carbonate of iron introduced into the waters, and afterwards precipitated as peroxide in the manner previously stated, and for the same reason, that I know none of the great formations of British rocks proved by fossils to be formed of ordinary marine sediment that possess this red colour, except those that have been stained from above by accident. I believe, therefore, that in this circumstance alone we have an indication that these red Permian strata were deposited in inland waters unconnected with the main ocean, which waters may have been salt or fresh, as the case may be.

What other circumstances are there that more or less bear on this question ?

First, as regards the plants of the British area, they are land-species, and chiefly of genera common in the Coal-measures, viz. Calamites, Lepidodendron, Walchia, Chondrites, Ullmannia, Cardiocarpon, Alethopteris, Sphenopteris, Neuropteris†, and many fragments of coniferous (?) wood of undetermined genera. These last are occasionally met with in the Permian red beds of many parts of England, generally silicified ; and inland waters would be likely to receive fragments of land-plants borne into them by rivers.

This, however, forms no conclusive evidence, since land-plants are not uncommon in the Lias and Oolites.

No Mollusca have yet been found in the red beds of Warwickshire, Staffordshire, Shropshire, Wales, or the Vale of Eden, with the exception of two or three casts of a brachiopod allied to Strophalosia, found by Mr. Gibbs and myself in red sandstones near Exhall, in Warwickshire ; and these occur along with Calamites and other land-plants. In Lancashire, however, near Manchester, Schizodus was found by Mr. Binney plentifully in Upper Red Permian marls, in

  • On the Physical Relations of the New Red Marl, Rhaetic beds, and Lower

Lias (supra, p. 190).

† Taken from Mr. Etheridge's lists.