In 1889 Williamson[642] described several specimens of petrified shoots from the Coal-Measures of Halifax which he named _Lepidodendron mundum_: these are now known to be branches of a _Bothrodendron_. The discovery was made by Mr Lomax[643] who found specimens showing the external characters of _Bothrodendron_ and the anatomical characters of _Lepidodendron mundum_. In some of the smaller twigs, the stele consists of a solid core of xylem with external protoxylem; but in the majority of specimens the centre of the xylem is replaced by parenchymatous tissue, either as a small axial strand or, as in the specimen shown in fig. 215, D, a wide pith, the elements of which are arranged in regular vertical series. A diagrammatic section of a small axis is represented in fig. 215, A: this branch, 2 mm. in diameter, is composed of a broad outer cortex consisting exclusively of primary tissue the outer cells of which are smaller and have thicker walls than the more internal elements. The leaf-traces, _lt_, are accompanied by a strand of delicate tissue, the parichnos. The stele is almost solid; the tissues in contact with the xylem have not been preserved but the inner cortex is represented by a few layers of small parenchymatous cells, _c_¹. The larger section shown in fig. 215, D, was cut from a specimen from Dulesgate of which the smooth surface exhibits the characteristic leaf-scars of _Bothrodendron_. The section measures 3 cm. in its longest diameter and the stele has a breadth of 3 mm. The outer cortex has a smooth surface and is composed of rather thick-walled cells succeeded by a zone of secondary elements. The middle cortex has disappeared and the space is partially occupied by Stigmarian rootlets, _s_, and crushed patches of cortical tissue. The position of a leaf-scar is seen at _a_; this is more clearly shown in the enlarged drawing fig. E.