The course of creation

by John Anderson

Now the important fact to be attended to in this experiment is, the wide geographical distribution during the carboniferous era of those tribes of plants which enter most certainly and abundantly into the composition of the coal metals. Many others may, and doubtless did, flourish within the period of the formation. But that the plants, possessed of the most conservative vegetable qualities, and the most capable of resisting solution in water, should be precisely the kinds which had then a universal range over the earth’s surface, can be ascribed to nothing else than to a wise predetermined purpose and arrangement. These plants were growing in every region. Every clime favored them—every soil nourished them. The bituminous product was intended for man’s use, whose family was destined to inhabit the whole earth. How irresistible the conclusion, corroborative of all the proofs of design derived from the nature and structure of the coal-measures, that, anticipating his wants and providing for his improvement, nature purposely constructed such forms of vegetable life, possessed, like the watch, with a compensation balance so as to suit every condition, and to thrive in every land; or, what is equally probable and consonant to the requirements of the problem, that there was such a uniformity of climate and temperature, and other chemical adjustments, as were most adapted to the peculiar and prevailing vegetation of the period.

IV. The Organic Remains we proceed to consider more in detail, where a remarkable contrast will be observed between the vegetable and animal types presented, so far as they have been respectively fossilized and preserved. The vegetables are nearly all of terrestrial, the animals are as generally and predominantly of marine, characters. Is this the result of blind chance, or of contrivance and foresight?

The plants of the coal epoch consist chiefly of the cryptogamia, and of these the ferns are the most abundant, composing, according to the estimate of M. Brongniart, about two-thirds of the entire carboniferous flora.

1. Sphenopteris linearis; 2. Pecopteris Mantelli; 3. Sphenopteris affinis.

The number of known existing ferns amounts to between seven and eight hundred, of which about fifty species belong to Great Britain, and upward of two hundred to the inter-tropical island of Jamaica. Nearly two hundred fossil species have been discovered in the British coal strata alone. The fossil genera most common to the district around, and occurring in every section of the great valley of the Scottish lowlands, are cyclopteris, neuropteris, pecopteris, and sphenopteris. The shales and clay-ironstones in which these beautiful plants are detected, are generally of a dark brownish color, while the impressions are all of the deepest jet, bringing out in lively contrast the complete cast of the fronds. There is a great resemblance between the specimens of extinct ferns and the existing families of our filices, now growing on every hill, brae, or mountain corrie; and, if this were all the difference, nature would seem to have departed but little from her original models. But the presumption is that most, if not all, the ferns of the coal era were trees which attained to a great height, and similar to the tree-ferns now growing so abundantly in the islands of the Pacific. The decorticated stems and trunks are deeply indented with scars, the markings, it is supposed, of the fronds which dropped from their feathery sides. This inference is borne out by the additional circumstance, that the fossils are generally much flattened and compressed, as would necessarily happen to succulent plants and such trees as consisted of the cellular tissue of the endogenous class. What a striking change in the vegetation of our country, where purple heaths, and cheerful grasses, and luxuriant corns, and forests of every tint and structure, have replaced the long green stems, and dark somber hues of the fern-clad regions of the olden times! The remains of this tribe are so numerous as to have stinted, one would suppose, or utterly to have prevented the growth and increase of every other order of plants, bringing before the imagination the scenes of our Australian colonies, so wild and wondrous to European eyes—and carrying back the mind to the vision of primeval ages, through a long succession of times and their events, the vista of an infant world.

The lycopodia, or club-moss tribe, are also very widely distributed among the coal-measures, and attained in the earlier ages of the earth’s history an equally gigantic size with the tree-ferns. At the present day, they are all weak, prostrate plants, of from two to three feet in length, and, following the same laws as the mosses and ferns, they are most abundant in hot, humid situations within the tropics, and especially in the smaller islands. As respects their botanical affinities, the lycopodiums are intermediate between ferns and coniferæ on the one hand, and ferns and mosses on the other; related to the first of those families in the abundance of annular ducts contained in their axis, and to the second in the whole aspect and outline of the stem of the larger kinds. Indeed, so great is the resemblance between lycopodia and certain coniferæ, that there is no other external character, except size, by which they can be distinguished; and, according to Professor Lindley, it is, at least, as probable that some of those specimens detected in the ancient flora of the world, which have been considered gigantic club-mosses, are really and truly pines, as that they are flowerless plants.

Another family of fossil plants abundant in the coal formation are the calamites, so named from their jointed reed-like structure. They attained to the size of trees, trunks upward of a foot in diameter being often met with, but still of such a soft succulent texture as to maintain the character of being, if reeds, easily shaken by the winds. These, and various specimens of the palm tribe, are to be found in every coal-field, and often in such vast masses as to show that they constituted no inconsiderable proportion of the flora of the period. Palms now only flourish within the regions of the tropics, where, from their various properties, as well as great productiveness as fruit-bearers, they constitute the chief source of dependence to the inhabitants for all their supplies of the necessaries, luxuries, and medicines of life. A single spathe of the date contains about 12,000 male flowers: another species has been computed to have 207,000 in a spathe, or 600,000 upon a single individual. The spathe constitutes the raceme or flower-stem of the tree, and on a single raceme of a Seje palm, Humboldt estimated the flowers at forty-four thousand, and the fruits at eight thousand. When these magnificent productions of nature covered the plains and marshes of our northern climes, there were no roaming tribes to gather their fruits, inhale their fragrance, or bask in their shades. And yet they were not formed in vain. Buried in the rocks, their collected remains now yield a product as useful and valuable to the human family—as contributive to intellectual improvement, as they would have been to mere animal enjoyment.

The genus sigillaria, one of the most common of the coal plants, possessed the singular properties of being apparently hollow in the center, yet with an inner woody axis floating in a woody succulent jelly, and inclosed in a thick outer coating of bark. The trunk is beautifully fluted with longitudinal parallel lines, regularly arranged along the surface, and dotted all over with small scars, as if impressed by the leaves penetrating through the bark into the central woody axis. The stigmariæ, once supposed to be a distinct genus, are now generally regarded as simply the roots of the sigillariæ; they are, for the most part, found resting in their natural position, in large clusters often; and forming with their dense matted fibers a floor of considerable thickness, on which, season after season, the leaves fell as the coaly matter accumulated. This tree grew to an enormous size, specimens of four feet in diameter by fifty feet in length being frequently met with; traces of a vascular and fibrous structure can be observed in the stems—also the annular wood layers are sometimes beautifully defined; and, combined with a coating of bark of an inch in thickness, the probability is, that the sigillaria belonged to the exogenous class of vegetables.