Caulopteris (_fern-stem_). _Lign. 31._--Stems not channelled, marked with discoidal, oblong, or ovate scars, arranged longitudinally; vascular cicatrices numerous. [Illustration: Lign. 31. Caulopteris macrodiscus. _Coal._] The fragment of stem here figured, resembles the trunks of some recent tree-ferns in its proportions, and in the number, disposition, and size, of the scars of the leaf-stalks; but these markings differ in their more lanceolate form, and pointed terminations, and in their peculiarly striated surface, from those of any known existing species. Psarolites (_Silicified Fern-Stems_).--In the New Red sandstone, near Hillersdorf, in the neighbourhood of Chemnitz, in Saxony, silicified stems, apparently of tree-ferns, occur in great numbers. They are remarkably beautiful, and the organization of the original is so well preserved by the silex, that slices, examined by the microscope, display the peculiar structure almost as perfectly as if the plants were recent: transverse sections exhibit the arched bundles of vascular fibres which compose the ligneous cylinder, surrounded by the cellular tissue. From the stellated markings produced by sections of the vessels that compose the tissues, and which are visible to the naked eye, these fossils have obtained the popular name of _Staaren-stein_, or Star-stone. The external surface of the specimens I have examined has a ligneous structure, and is of a dark reddish brown colour; internally the stems are of a dull red, mottled with various tints of blue and yellow, from the infiltrated chalcedony with which the vessels are permeated.[89] [89] See Pict. Atlas (pl. viii.) for coloured figures; and Org. Rem. vol. L plate viii. _figs._ 1-7. The reader will be amused by the perusal of the ingenious but unsuccessful attempt of the excellent author, Mr. Parkinson, to elucidate their nature. I have still a specimen which he presented to me more than thirty-five years since, as one of the most curious and perplexing fossils that had ever come under his notice.