Popular Science Monthly/Volume 32/April 1888/Chinese Superstitions
arranged in concentric zones, which, if annual rings, would in some specimens indicate an age of one hundred and fifty years. There are also radiating spaces, which I was at first disposed to regard as true medullary rays, or which at least indicate a radiating arrangement of the tissue. They now seem to be spaces extending from the center toward the circumference of the stem, and to have contained bundles of tubes gathered from the general tissue and extending outward perhaps to organs or appendages on the surface. That the plant grew on land I can not doubt, from its mode of occurrence; that it was of durable and resisting character is shown by its state of preservation; and the structure of the seeds called Pachytheca, with their constant association with these trees, give countenance to the belief that they are the fruit of Nematophyton. Of the foliage or fronds of these
Fig. 4. — Nematophyton Logani (magnified) Restoration.
strange plants we unfortunately know nothing. They seem, however, to realize the idea of arboreal plants having structures akin to those of thallophytes, but with seeds so large and complex that they can scarcely be regarded as mere spores.
Multitudes of markings occurring on the surfaces of the older rocks have been referred to the algae or sea-weeds, and indeed this group has been a sort of refuge for the destitute to which paleontologists have been accustomed to refer any anomalous or inexplicable form which, while probably organic, could not be definitely referred to the animal kingdom. There can be no question that some of these are truly marine plants; and that plants of this kind occur in formations older than those in which we first find land-plants, and that they have continued to inhabit the sea down to the present time. It is also true that the oldest of these algae closely resemble in form plants of this kind still existing; and, since their simple cellular structures and soft tissues are scarcely ever preserved, their general forms are all that we can know, so that their exact resemblance to or difference from modern types can rarely be determined. For the same reasons it has proved difficult clearly to distinguish them from mere inorganic markings or the traces of animals, and the greatest divergence of opinion has occurred in recent times on these subjects.
|Fig. 5. — Buthotrepis Grantii. a genuine Alga from the Silurian, Canada.|
The author of this work has given much attention to these remains, and has not been disposed to claim for the vegetable kingdom so many of them as some of his contemporaries. I believe there are many real examples of fossil algæ, but the difficulty is to distinguish them.
The genus Buthotrephis of Hall, which is characterized as having stems, subcylindric or compressed, with numerous branches, which are divaricating and sometimes leaf-like, contains some true algæ. A beautiful species, collected by Colonel Grant, of Hamilton, and now in the McGill College collection, may be described as follows:
Butthotrephis Grantii, S. N. (Fig. 5). — Stems and fronds smooth and slightly striate longitudinally, with curved and interrupted stride. Stem thick, bifurcating, the divisions terminating in irregularly pinnate fronds, apparently truncate at the extremities. The quantity of carbonaceous matter present would indicate thick, though perhaps flattened, stems and dense fleshy fronds. It may be well to mention the remarkable Cauda-Galli fucoids, referred by Hall to the genus Spirophyton, and which are characteristic of the oldest Erian beds. The specimens which I have seen from New York, from Gaspé, and from Brazil, leave no doubt in my mind that these were really marine plants, and that the form of a spiral frond, assigned to them by Hall, is perfectly correct. They must have been very abundant and very graceful plants of the early Erian, immediately after the close of the Silurian period.
It is not surprising that great difficulties have occurred in the determination of fossil algae. Enough, however, remains certain to prove that the old Cambrian and Silurian seas were tenanted with sea-weeds not very dissimilar from those of the present time. It is further probable that some of the graphitic, carbonaceous, and bituminous
Fig. 6. — Silurian Vegetation Restored. Profannularia, Berwynia. Nemafophyton, Sphenophyllum, Arthrostigma, Psilophyton.
shales and limestones of the Silurian owe their carbonaceous matters to the decomposition of algae, though possibly some of it may have been derived from graptolites and other corneous zoöphytes. In any case, such microscopic examinations of these shales as I have made, have not produced any evidence of the existence of plants of higher grade, while those of the Erian and Carboniferous periods, similar to the naked eye, abound in such evidence. It is also to be observed that, on the surfaces of beds of sandstone in the Upper Cambrian, carbonaceous debris, which seems to be the remains of either aquatic or land plants, is locally not infrequent.
Referring to the land vegetation of the older rocks, it is difficult to picture its nature and appearance. We may imagine the shallow waters filled with aquatic or amphibious rhizocarpean plants, vast meadows or brakes of the delicate Psilojihyton and the starry Protan- nularia and some tall trees, perhaps looking like gigantic club-mosses, or possibly with broad, flabby leaves, mostly cellular in texture, and resembling algJB transferred to the air. Imagination can, however, scarcely realize this strange and grotesque vegetation, which, though possibly copious and luxuriant, must have been simple and monoto- nous in aspect, and, though it must have produced spores and seeds and even fruits, these were probably all of the types seen in the modem acrogens and gymnosperms.
"In garments green, indistinct in the twilight, They stand like Druids of old, with voices sad and prophetic."
Prophetic they truly were of the more varied forests of succeeding times, and they may also help us to realize the aspect of that still older vegetation, which is fossilized in the Laurentian graphite; though it is not impossible that this last may have been of higher and more varied types, and that the Cambrian and Silurian may have been times of depression in the vegetable world, as they certainly were in the submergence of much of the land.
These primeval woods served at least to clothe the nakedness of the new-born land, and they may have sheltered and nourished forms of land-life still unknown to us, as we find as yet only a few insects and scorpions in the Silurian. They possibly also served to abstract from the atmosphere some portion of its superabundant carbonic acid harmful to animal life, and they stored up supplies of graphite, of petroleum, and of illuminating gas, useful to man at the present day. We may write of them and draw their forms with the carbon which they themselves supplied.
The considerations adduced by Professor Alfred Marshall, in answer to the question whether London is healthy, are applicable to other large cities. Many people live long in the metropolis, not because it is healthy, but because their exceptional health and strength induced them to come there. Most of the in- habitants who wore born elsewhere were, when they came, the picked lives, the strongest members of their several parishes. Kumbers of London-born people have gone away to live elsewhere because they felt themselves unequal to the strain of metropolitan life. The death-rate of young women is low, partly be- cause of the favorable conditions of life of domestic servants, and partly because young people who come to the city are likely to go home as soon as they get ill, to swell, perhaps, the death-rate of their native towns. Really, London is very unhealthy; for, although the population consists mainly of picked lives, and despite all the resources of wealth to counteract disease, the expectation of life is below the average.
- Figs. 2, 3, and 4 are drawn from nature, by Professor Penhallow, of McGill College.
- "Impressions and Footprints of Aquatic Animals," "American Journal of Science," 1873.