Vestiges of the Natural History of Creation

by Robert Chambers

Organic beings are, then, bound together in development, and in a system of both affinities and analogies. Now, it will be asked, does this agree with what we know of the geographical distribution of organic beings, and of the history of organic progress as delineated by geology? Let us first advert to the geographical question.

Plants, as is well known, require various kinds of soil, forms of geographical surface, climate, and other conditions, for their existence. And it is everywhere found that, however isolated a particular spot may be with regard to these conditions,—as a mountain top in a torrid country, the marsh round a salt spring far inland, or an island placed far apart in the ocean,—appropriate plants have there taken up their abode. But the torrid zone divides the two temperate regions from each other by the space of more than forty-six degrees, and the torrid and temperate zones together form a much broader line of division between the two arctic regions. The Atlantic and Pacific Oceans, and the Persian Gulf, also divide the various portions of continent in the torrid and temperate zones from each other. Australia is also divided by a broad sea from the continent of Asia. Thus there are various portions of the earth separated from each other in such a way as to preclude anything like a general communication of the seeds of their respective plants towards each other. Hence arises an interesting question—Are the plants of the various isolated regions which enjoy a parity of climate and other conditions, identical or the reverse? The answer is—that in such regions the vegetation bears a general resemblance, but the species are nearly all different, and there is even, in a considerable measure, a diversity of families.

The general facts have been thus stated: in the arctic and antarctic regions, and in those parts of lower latitudes, which, from their elevation, possess the same cold climate, there is always a similar or analogous vegetation, but few species are common to the various situations. In like manner, the intertropical vegetation of Asia, Africa, and America, are specifically different, though generally similar. The southern region of America is equally diverse from that of Africa, a country similar in clime, but separated by a vast extent of ocean. The vegetation of Australia, another region similarly placed in respect of clime, is even more peculiar. These facts are the more remarkable when we discover that, in most instances, the plants of one region have thriven when transplanted to another of parallel clime. This would shew that parity of conditions does not lead to a parity of productions so exact as to include identity of species, or even genera. Besides the various isolated regions here enumerated, there are some others indicated by naturalists as exhibiting a vegetation equally peculiar. Some of these are isolated by mountains, or the interposition of sandy wastes. For example, the temperate region of the elder continent is divided about the centre of Asia, and the east of that line is different from the west. So also is the same region divided in North America by the Rocky Mountains. Abyssinia and Nubia constitute another distinct botanical region. De Candolle enumerates in all twenty well-marked portions of the earth’s surface which are peculiar with respect to vegetation; a number which would be greatly increased if remote islands and isolated mountain ranges were to be included.

When we come to the zoology, we find precisely similar results, excepting that man (with, perhaps, some of the less conspicuous forms of being) is universal, and that several tribes, as the bear and dog, appear to have passed by the land connexion from the arctic regions of the eastern to those of the western hemisphere. “With these exceptions,” says Dr. Prichard, “and without any others, as far as zoological researches have yet gone, it may be asserted that no individual species are common to distant regions. In parallel climates, analogous species replace each other; sometimes, but not frequently, the same genus is found in two separate continents; but the species which are natives of one region are not identical with corresponding races indigenous in the opposite hemisphere.

“A similar result arises when we compare the three great intertropical regions, as well as the extreme spaces of the three great continents, which advance into the temperate climates of the southern hemisphere.

“Thus, the tribes of simiæ, (monkeys,) of the dog and cat kinds, of pachyderms, including elephants, tapirs, rhinoceroses, hogs, of bats, of saurian and ophidian reptiles, as well of birds and other terrene animals, are all different in the three great continents. In the lower departments of the mammiferous family, we find that the bruta, or edendata, (sloths, armadillos, &c.,) of Africa, are differently organized from those of America, and these again from the tribes found in the Malayan archipelago and Terra Australis.” [255]

It does not appear that the diversity between the similar regions of Africa, Asia, and America, is occasioned in all instances by any disqualification of these countries to support precisely the same genera or species. The ox, horse, goat, &c., of the elder continent have thriven and extended themselves in the new, and many of the indigenous tribes of America would no doubt flourish in corresponding climates in Europe, Asia, and Africa. It has, however, been remarked by naturalists unacquainted with the Macleay system, that the larger and more powerful animals of their respective orders belong to the elder continent, and that thus the animals of America, unlike the features of inanimate nature, appear to be upon a small scale. The swiftest and most agile animals, and a large proportion of those most useful to man, are also natives of the elder continent. On the other hand, the bulk of the edentata, a group remarkable for defects and meanness of organization, are American. The zoology of America may be said, upon the whole, to recede from that of Asia, “and perhaps in a greater degree,” adds Dr. Prichard, “from that of Africa.” A much greater recession is, however, observed in both the botany and zoology of Australia.

There “we do not find, in the great masses of vegetation, either the majesty of the virgin forests of America, or the variety and elegance of those of Asia, or the delicacy and freshness of the woods of our temperate countries of Europe. The vegetation is generally gloomy and sad; it has the aspect of our evergreens or heaths; the plants are for the most part woody; the leaves of nearly all the plants are linear, lanceolated, small, coriaceous, and spinescent. The grasses, which elsewhere are generally soft and flexible, participate in the stiffness of the other vegetables. The greater part of the plants of New Holland belong to new genera; and those included in the genera already known are of new species. The natural families which prevail are those of the heaths, the proteæ, compositæ, leguminosæ, and myrthoideæ; the larger trees all belong to the last family.” [257]

The prevalent animals of Australia are not less peculiar. It is well known that none above the marsupialia, or pouched animals, are native to it. The most conspicuous are these marsupials, which exist in great varieties here, though unknown in the elder continent, and only found in a few mean forms in America. Next to them are the monotremata, which are entirely peculiar to this portion of the earth. Now these are animals at the bottom of the mammiferous class, adjoining to that of birds, of whose character and organization the monotremata largely partake, the ornithorynchus presenting the bill and feet of a duck, producing its young in eggs, and having, like birds, a clavicle between the two shoulders. The birds of Australia vary in structure and plumage, but all have some singularity about them—the swan, for instance, is black. The country abounds in reptiles, and the prevalent fishes are of the early kinds, having a cartilaginous structure.

Altogether, the plants and animals of this minor continent convey the impression of an early system of things, such as might be displayed in other parts of the earth about the time of the oolite. In connexion with this circumstance, it is a fact of some importance, that the geognostic character of Australia, its vast arid plains, its little diversified surface and consequent paucity of streams, and the very slight development of volcanic rock on its surface, seem to indicate a system of physical conditions, such as we may suppose to have existed elsewhere in the oolitic era: perhaps we see the chalk formation preparing there in the vast coral beds frontiering the coast. Australia thus appears as a portion of the earth which has, from some unknown causes, been belated in its physical and organic development. And certainly the greater part of its surface is not fitted to be an advantageous place of residence for beings above the marsupialia, and judging from analogy, it may yet be subjected to a series of changes in the highest degree inconvenient to any human beings who may have settled upon it.