Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/766

 3. On a new Labyrinthodont Amphibian from the Magnesian Limestone of Midderidge, Durham. By Albany Hancock, Esq., F.L.S., and Richard Howse, Esq.

(Communicated by Prof. Huxley, F.R.S., F.G.S.)

[Plate XXXVIII.]

Among the important additions to the fauna of the Permian rocks of Durham made by Joseph Duff, Esq., last autumn, not the least interesting, perhaps, may be reckoned the remains of a Labyrinthodont having numerous finely striated, rhombiform scutes or scales, resembling in shape those of some Ganoid fishes, though very superior in size. These remains were found at the Midderidge quarry (a portion of which has recently been removed for the purpose of widening the Darlington and Wear-valley Railway), in a bed of yellow marly limestone 7 or 8 feet above the marl-slate properly so called. The section at this quarry is thus described by Prof. Sedgwick, Geol. Trans, ser. ii. vol. iii. p. 76 : —

" 1. Bed of light-coloured siliceous sandstone, worked as a coarse flagstone and also as a building-stone. The upper beds alternate with blue-coloured calcareous shale. At East Thickley they are about 30 feet thick.

" 2. Yellow-coloured calcareous shale and shale-slate, in thickness about 9 feet. Some of these beds are incoherent and sandy ; the marl-slate forms a series of indurated bands, which divide the more incoherent shale.

" 3. A series of thin beds with marly partings ; the whole about 20 feet thick. The average thickness of the several beds is not more than a few inches ; their surfaces are often covered with yellow marl ; at their natural partings they are generally covered with dendritical impressions," etc.

In the above section, No. 1 represents the uppermost member of the Coal-measures, which in this part of Durham have been much disturbed and denuded prior to the deposition of the Marl-slate. It must be mentioned that in this quarry and in the south of Durham there is no bed of " yellow incoherent sand," a bed which forms an important item in the section a few miles further north and in the north of Durham generally.

The Marl-slate proper equals the lower portion of No. 2 of Prof. Sedgwick's section. When closely examined, it can be distinctly separated from the marly limestone, into which it gradually passes upwards. And it is more emphatically distinguished by the fossils it contains ; for, though a few stray fishes are now and then found in the calcareous beds above, yet this lowest part is the depository for the numerous fish- and plant-remains which characterize the Permian rocks. It is, then, in the middle, or nearly so, of this yard of Marl- slate that Mr. Duff has found the remains of the Dorypterus Hoffmanni, Germar, and also the remains of two species of reptiles, viz. Proterosaurus Speneri, H. v. Meyer, and Proterosaurus Huxleyi, nov. spec., descriptions of which have been communicated to the Geological Society. Associated with these occurred numerous re-