This stem is probably the upper part of one or other of the species of _Psaronius_ found in the same bed (_P. Erianus_, Dawson, and _P. textilis_, Dawson).[BG] It appears to have been an erect stem embedded in situ in sandstone, and preserved as a cast. The stem is small, being only two inches, or a little more, in diameter. It is coarsely wrinkled longitudinally, and covered with large leaf-scars, each an inch in diameter, of a horseshoe-shape. The petioles, five of which remain, separate from these scars with a distinct articulation, except at one point near the base, where probably a bundle or bundles of vessels passed into the petiole. They retain their form at the attachment to the stem, but a little distance from it they are flattened. They are inflated at the base, and somewhat rapidly diminish in size. The leaf-scars vary in form, and are not very distinct, but they appear to present a semicircular row of pits above, largest in the middle. From these there proceed downward a series of irregular furrows, converging to a second and more obscure semicircle of pits, within or below which is the irregular scar or break above referred to. The attitude and form of the petioles will be seen from Fig. 24, _supra_. [BG] Memoir on Devonian Flora, "Proceedings of the Royal Society," May, 1870. The petioles are broken off within a few inches of the stem; but other fragments found in the same beds appear to show their continuation, and some remains of their foliage. One specimen shows a series of processes at the sides, which seem to be the remains of small pinnæ, or possibly of spines on the margin of the petiole. Other fragments show the division of the frond, at first in a pinnate manner, and subsequently by bifurcation; and some fragments show remains of pinnules, possibly of fertile pinnules. These are very indistinct, but would seem to show that the plant approached, in the form of its fronds and the arrangement of its fructification, to the Cyclopterids of the sub-genus _Aneimites_, one of which (_Aneimites Acadica_), from the Lower Carboniferous of Nova Scotia, I have elsewhere described as probably a tree-fern,[BH] The fronds were evidently different from those of _Archæopteris_[BI] a genus characteristic of the same beds, but of very different habit of growth. This accords with the fact that there is in Prof. Hall's collection a mass of fronds of _Cyclopteris_ (_Archæopteris_) Jacksoni, so arranged as to make it probable that the plant was an herbaceous fern, producing tufts of fronds on short stems in the ordinary way. The obscurity of the leaf-scars may render it doubtful whether the plant above described should be placed in the genus _Caulopteris_ or in _Stemmatopteris_; but it appears most nearly allied to the former. The genus is at present, of course, a provisional one; but I have thought it only justice to the diligent labours of Mr. Lockwood to name this curious and interesting fossil _Caulopteris Lockwoodi_.