4. On new Tree Ferns and other Fossils from the Devonian. By J. W. Dawson, LL.D., F.R.S., F.G.S., Principal of M'Gill College, Montreal.
[Plate XII.]
Of the numerous ferns now known in the Middle and Upper Devonian of North America, a great number are small and delicate species, which were probably herbaceous ; but there are other species which may have been tree ferns. Little definite information, however, has, until recently, been obtained with regard to their habit of growth.
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 (Quart. Journ. Geol. 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 aerial roots, which I have described as Psaronius tectilis and P. erianus in my 'Revision of the Devonian Flora,' now in the hands of the Royal Society*. In the same collection were two very large petioles, Rhachiopteris gigantea and R. palmata, which I have suggested may have belonged to tree ferns.
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 aerial 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, and on a remarkable plant from the Devonian of Caithness, kindly placed in my hands by Dr. Wyville Thomson.
It may be further observed that the Gilboa specimens are from a bed containing erect stumps of tree ferns, in the Chemung group
- Abstract in Proceedings of Royal Society, May 1870.
VOL. XXVII. PART I. U
