The specimen is nine inches in diameter, and presents throughout a series of rings of growth, rather more than one-tenth of an inch in average thickness. Under the microscope, the crosssection exibits cells perfectly circular in outline, not crowded, but becoming much smaller at the margins of the rings of growth, where some large irregular openings perhaps represent resinducts. The medullary rays are marked by clear structureless spaces. In the longitudinal section, parallel to the medullary rays, the wood-cells are seen to be much elongated, and to terminate in conical points; and their sides are covered with the remains of a double series of spiral fibres, among which are a few scattered roundish spots, which perhaps indicate a single row of discs. The cells of the medullary rays have been entirely disorganized; but the space which represents them in a tangential slice, shows that they must have consisted of several rows of cells. (Figs. 4 a-c.) In my late visit to Gaspé, I was so fortunate as to find a second tree of this species imbedded in the strata, though having its structure in a less perfect state of preservation than the specimen above described. It was in a prostrate position, the trunk lying S. W. and N. E., in a thinly bedded, crumbling, pyritous sandstone. The trunk is silicified, one foot five inches in its greatest diameter, and eleven inches in its least, the difference being due to compression; a branch five inches in diameter sprang from its side. On the external surface was a thin layer of crumbling coal, probably representing the bark. No pith was perceptible; but there was a channel or depression along the upper surface, as if a pith-cavity had existed and, when the wood became softened by decay, had given way to pressure. The age of this tree, as indicated by its rings of growth, would be about one hundred and fifty years; so that, though the tissue appears lax, it was not of more rapid growth than in modern conifers. The growth-rings also in the specimen previously described, as well as in this, are well marked, indicating a decided difference of temperature in the seasons of the Devonian year. I cannot propose for this monarch of the old Devonian forests of Gaspé a better or more appropriate name than that of its discoverer, and shall therefore name it Prototaxites Logani. This disc-like structure was first pointed out to me by Mr. Poe, of Montreal, a very zealous and successful microscopist. With respect to the affinities of the genus, I can only say that the markings on its wood-cells most nearly resemble those of the two genera of fossil Taxine trees above-mentioned, which are, however, found in much more modern geological formations. Among recent trees known to me by specimens or figures of their tissues, Taxus baccata and Torreya taxifolia most nearly resemble the Gaspé fossil. In the meantime, therefore, it may be included in the subfamily Taxinea. I could detect no leaves or fruit likely to belong to the species; but this is not wonderful, since in the Coal-formation the wood of conifers is very abundant, while their foliage is extremely rare. Before leaving this ancient taxine conifer, it may be useful to notice the deceptive appearances which its wood presents when imperfectly preserved. In some parts of my second specimen the woody tissue has been entirely obliterated, and is replaced by a kind of oolitic concretionary structure, apparently connected with the presence of iron-pyrites. In other portions the wood seems to have been resolved into a homogeneous paste before silicification; and this, being moulded on minute granular crystals of quartz, assumes the aspect of a tissue of fine parenchymatous cells a deceptive appearance very common in badly preserved fossils penetrated by calcareous or silicious matter. In other parts of the specimen the cell-walls remain, but in an opaque coaly condition, which conceals their spiral fibres and discs. I am not quite certain that this last form may not represent the natural state of the heart-wood of the tree. In the first specimen, obtained by Sir W. E. Logan, the whole trunk appears to be well preserved, with the exception of the medullary rays. 4. POACITES, KNORRIA (fig. 5), CARBONIZED WOOD (fig. 6), ETC. In addition to the plants above described, the Gaspé sections. contain, especially in the beds near the coal-seam, abundance of what seem to be long parallel-sided leaves, with delicate longitudinal striæ, and varying from a fourth of an inch to an inch, in breadth. They may be placed provisionally in the genus Poacites, but are perhaps leaves of Naggerathia or Cordaites. Fig. 5 a There is also in the Collection of the Geological Survey of Canada a remarkable fragment, covered with sharp, flat, angular scales. Were it not for its carbonaceous character, I should be inclined to regard it as of animal rather than vegetable origin. If a plant, it must, I presume, be referred to the genus Knorria (see fig. 5). In the same collection is a flattened and obscurely marked stem, from rocks of the same age at Kettle Point, Lake Huron. Its markings are scarcely sufficiently distinct for description, but cannot be distinguished from those of some of the varieties of Knorria imbricata. Another suite of specimens in the Museum of the Geological Survey indicates the existence of a large plant, the precise nature of which it is perhaps at present impossible to determine. One of the specimens from Gaspé has the aspect of a long flattened trunk, having in a few places the remains of a carbonaceous coating, presenting longitudinal ribs like those of Calamites. It is crossed at intervals by markings not quite at right angles to the sides of the stem, each of which consists of a sharp ridge with a furrow at either side. The specimen is four inches in breadth and about four feet in length. Other specimens from Kettle Point vary from five inches to one inch in breadth; and some of them show traces of longitudinal ribs, but others are quite smooth, or marked only by the rhombic structure-lines of the coaly matter. All show transverse or diagonal ridges, though some of these seem to be merely cracks filled with mineral matter. Crushed Calamites, in a very bad state of preservation, might assume these appearances; but, until better specimens occur, the true nature of these plants must remain doubtful. They are very possibly of the same nature with the Calamite-like stems described by Miller in his Testimony of the Rocks,' p. 439. In every part of the Gaspé sections, beds occur having their surfaces thickly covered with fragments of carbonized vegetable matter, evidently drifted by the currents which deposited the sand composing the beds. A large proportion of these comminuted plants belong to the genus Peilophyton; but many are fragments of the wood of larger vegetables. Nearly all are in a very imperfect state of preservation; and most of those that retain their structure show a scalariform tissue similar to that represented in fig. 6, and probably belong to the axis of LepidodenFig. 6. Scalariform tissue dron. Others exhibit elongated woody (magnified 300 diams.) cells, without minute markings, perhaps Fig. 6. from the cortical portion of the same genus, or possibly coniferous*. Another form of carbonaceous matter, abundant in some of the sandstones, consists of scaly fragments resembling the remains of decayed cones, probably Lepidostrobi. The great abundance of vegetable fragments throughout an immense thickness of rock, indicates the existence of extensive land surfaces clothed with vegetation, though this apparently consisted of but a few species. The small bed of coal occurring in the lower part of the section, is composed entirely of irregularly laminated shining coaly matter without mineral charcoal. From its appearance and the vegetable remains in its underclay, I infer that it consists principally of the accumulated rhizomata of Psilophyton, in situ. Its roof-shale is filled with the Poacites-like leaves before mentioned, and with stems of Psilophyton; and it is remarkable that these last are in great part coiled up in the state of vernation, as if overwhelmed by a succession of spring floods. 5. ANIMAL REMAINS, RAIN-MARKS, ETC. The animal remains found in the plant-beds were Entomostraca (Beyrichia), Spirorbis (resembling that of the coal-measures), Worm-tracks, and Ichthyodorulites (Onchus and Machæracanthust). In one of the beds above the coal Sir W. E. Logan found a few brachiopodous shells, apparently identical with those at the base of the series, and also some remarkable transversely marked furrows, which may have been produced by worms or by marine gasteropods. Near the upper part of the section, where the plants become more rare, and the rocks are more abundantly tinged with the red peroxide of iron, the beds are plentifully and often very grotesquely marked with ripple-furrows, shrinkage-cracks, and currentlines. In one or two beds there are surfaces covered with rounded projections resembling casts of rain-marks; and in proof that this is their true character, the surface being irregular, we have not only the rain-marks themselves, but the little rills formed by the gathering drops as they rolled along, in this one of the most ancient showers of which we have as yet any geological record. The general character of the conditions indicated by the Devonian rocks and flora of Gaspé does not differ materially from that * Aporoxylon (Unger). † Prof. Newberry regards one of these as identical with his Macheracanthus sulcatus from the Devonian of Ohio. of the Carboniferous period, though the vegetation would appear to have been poorer in species and more exclusively Lycopodiaceous; in which respects it more nearly resembles that of the Lower than of the Middle or Upper Coal-measures. The general history is that of a sea-bottom elevated or filled up in such a manner as to afford sandy or muddy flats, on portions of which plants grew, and on other portions vegetable fragments were drifted, or bare surfaces were exposed to the alternate influences of aqueous deposition and aërial desiccation,-these various conditions being more or less prevalent throughout a long period, during which the area may have been gradually sinking, to be again disturbed and elevated at the commencement of the Carboniferous period. In explanation of the siliceous and plant-bearing character of the Gaspé beds, as compared with their more calcareous and marine character in some other parts of America, I may point to their vicinity to the old Laurentian land on the north side of the Gulf of St. Lawrence, and to the possible existence of a nearer belt of Lower Silurian land, indicated by the unconformability, in this part of Canada, of the Lower and Upper Silurian rocks. In the collection of Sir W. E. Logan there are some vegetable remains from the limestones of Cape Gaspé and its vicinity, which perhaps indicate a still older terrestrial flora than that above described. They afford, I think, evidence of the existence of at least one species of Psilophyton and one of Naggerathia or Poacites; but whether identical or not with those above described, I cannot determine from the specimens. The beds in which they occur certainly underlie the Gaspé sandstones, and are probably Upper Silurian. ARTICLE II.-List of Plants found growing as indigenous in the neighbourhood of Prescott, C. W.; for the most part, collected in 1859, by W. E. BILLINGS. (Supplementary to Article 6, "Canadian Naturalist," February, 1858.) Ranunculacea. Anemone cylindrica, (Gray). Thickets; westward; common. Ranunculus aquatilis (L.), var. divaricatus. Ponds, &c.; common. northward. |