are remains of what he considers a minute air-breathing Batrachian, with teeth like those of Dendrerpeton and the frog, and which he has named Gastrodus propositus. Associated with fish-remains are usually numbers of Entomostraca (Beyrichita arcuata, and Cytheropsis scoto-burdigalensis), which appear to have acted like scavengers in the carboniferous waters, clearing away the decomposing flesh of the fish. Remains of insects, nearly allied to the genus Blatta, have been detected by Mr. Kirkby in an ironstone band, near the top of the Coal Measures, on the north bank of the Wear, opposite Claxheugh. Plants, however, are the distinguishing organisms of the Coal Measures; they had grown in vast abundance on the ancient swampy ground of the Carboniferous era, and they supplied the material which forms the coal beds. A few coniferous trees flourished at this era, and the following species have been determined: Picea Withami, Pinites ambigua and anthracina, Dadoxylon approximatus and Brandlingi; but the most abundant plants are Sigillariae, of which thirteen species have been noticed; and they appear to have furnished a large proportion of the vegetable matter forming coal, since their roots, the Stigmaria ficoides, are in great numbers in the clay underlying each coal seam. Of Lepidodendra there are eleven species, and of Calamites seven. Fronds of ferns were in great profusion, and of these fifty species have been recorded, though probably not a few have been determined from different parts of the same plant.
The Carboniferous system has been uplifted and dislocated at different periods. The last upheaval of the Cheviots tilted up the lower strata; and the basaltic protrusions of a later time produced considerable disturbance. But the effects of the greatest elevating force affecting our district are seen in the Penine chain, extending from Tindale Pell southward about 60 miles; for along this line of mighty fracture the Mountain Limestone beds on the east side have been thrust upward, in some parts, near to 3000 feet—and this stupendous mountain wall rises some 2500 feet above the New Red Sandstone plain lying on the west. The Stublick and the Ninety-fathom Dikes are probably secondary effects of this disruption. By the Ninety-fathom Dike, which
