Geology and Mineralogy considered with reference to Natural Theology/Plate 26‴

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Geology and Mineralogy considered with reference to Natural Theology, plate 26‴.png

Plate 26‴. V. I. p. 203.

Footsteps of a small web-footed animal, probably crocodile an, drawn from a Cast of impressions on Sandstone, found near Hildburghausen. (Original.)

The Sandstones in which all these fossil footsteps have been discovered in Germany and Scotland, appear to be referable to the same division of the secondary strata, which lies in the middle region of that large, and widely extended series of Sandstones, and Conglomerates, Limestones, and Marl, which English Geologists have usually designated by the common appellation of the New red Sandstone Group, including all the strata that are interposed between the Coal formation, and the Lias.

M. Brongniart, in his Terrain de l'Écorce du Globe, 1829, has applied to this middle division the very appropriate name of Terrain Poscilien, (from the Greek voixiXog), a term equivalent to the names Bunter Sandstein, and Grès bigarré, which it bears in Germany and France; and indicating the same strata which, in England, we call the new Red Sandstone. (See Plate 1. Section No. 17.)

Mr. Conybeare, in his Report on Geology to the British Association at Oxford, 1832 (Page 379, and P. 405, Note,) has proposed to extend the term Pœcilitic to the entire Group of strata between the Coal formation and the Lias; including the five formations designated in our section (Pl. 1, No. 15, 16, 17, 18, 19,) by the names of New Red Conglomerate, Magnesian Limestone, Variegated Sandstone, Shell Limestone, and Variegated Marl. Some common appellative for all these formations has been long a desideratum in Geology; but the word Pœcilitic is in sound so like to Pisolite, that it may be better to adhere more literally to the Greek root tfoixfXos, and apply the common name of Poikilitic group to the strata in question.[1]

  1. The general reception of such a common name for all these strata, and the reception of the Grauwacke series into the Cambrian and Salurian systems, as proposed by Professor Sedgwick and Mr. Murchison, will afford three nearly equal and most convenient groups or systems, into which the strata composing the Transition and Secondary series may respectively be divided; the former comprehending the Cambrian, Salurian, and Carboniferous systems, and the latter comprehending the Poikilitic, Oolitic, and Cretaceous Groups.