The only species known to me in the Devonian of Europe is the _Caulopteris Peachii_ of Salter, figured in the "Quarterly Journal of the Geological Society" for 1858. The original specimen of this I had an opportunity of seeing in London, through the kindness of Mr. Etheridge, and have no doubt that it is the stem of a small arborescent fern, allied to the genus _Caulopteris_, of the coal formation. In my paper on the Devonian of Eastern America ("Quarterly Journal of the Geological Society," 1862), I mentioned a plant found by Mr. Richardson at Perry, as possibly a species of _Megaphyton_, using that term to denote those stems of tree-ferns which have the leaf-scars in two vertical series; but the specimen was obscure, and I have not yet obtained any other. More recently, in 1869, Prof. Hall placed in my hands an interesting collection from Gilboa, New York, and Madison County, New York, including two trunks surrounded by aërial roots, which I have described as _Psaronius textilis_ and _P. Erianus_, in my "Revision of the Devonian Flora," read before the Royal Society.[BF] In the same collection were two very large petioles, _Rhachiopteris gigantea_ and _R. palmata_, which I have suggested may have belonged to tree-ferns. [BF] Abstract in "Proceedings of the Royal Society," May, 1870; also "Report on Erian Plants of Canada," 1871. My determination of the species of _Psaronius_, above mentioned, has recently been completely confirmed by the discovery on the part of Mr. Lockwood, of Gilboa, of the upper part of one of these stems, with its leaf-scars preserved and petioles attached, and also by some remarkable specimens obtained by Prof. Newberry, of New York, from the Corniferous limestone of Ohio, which indicate the existence there of three species of tree-ferns, one of them with aërial roots similar to those of the Gilboa specimens. The whole of these specimens Dr. Newberry has kindly allowed me to examine, and has permitted me to describe the Gilboa specimen, as connected with those which I formerly studied in Prof. Hall's collections. The specimens from Ohio he has himself named, but allows me to notice them here by way of comparison with the others. I shall add some notes on specimens found with the Gilboa ferns. It may be further observed that the Gilboa specimens are from a bed containing erect stumps of tree-ferns, in the Chemung group of the Upper Devonian, while those from Ohio are from a marine limestone, belonging to the lower part of the Middle Devonian. 1. _Caulopteris Lockwoodi_, Dawson.--Trunk from two to three inches in diameter, rugose longitudinally. Leaf-scars broad, rounded above, and radiatingly rugose, with an irregular scar below, arranged spirally in about five ranks; vascular bundles not distinctly preserved. Petioles slender, much expanded at the base, dividing at first in a pinnate manner, and afterwards dichotomously. Ultimate pinnæ with remains of numerous, apparently narrow pinnules.