THE FAR PAST.

PALEOZOIC SYSTEMS-THE CAMBRIAN, SILURIAN, DEVONIAN, CARBONIFEROUS, AND PERMIAN.

ON glancing over the existing forms of the vegetable and animal kingdoms, struck as we may be at first by their wondrous variety and complexity, we gradually begin to detect innumerable affinities that link one family to another, and at length perceive that one plan and purpose runs throughout the whole. In like manner, when we turn to the still stranger and more complicated forms of the Past, and blend them with those of the Present-varied and endless as the details may appear-they gradually coalesce into one unbroken sequence of design, from the morning that first dawned on infant life, to the sunset that closed around us but a few hours ago. Without this uniformity in purpose and design, the study of nature would be impossible: we can only reason respecting the past from our knowledge of the present, and predict of the future from what is now taking place around us. And here at the outset we must specially guard against the misconception that in the Past Life of the globe we are to meet with anything that is monstrous or abnormal. As in the physical world we have no evidence of the operation of "aberrant" or "cataclysmal" or "revolutionary" forces, so in the vital world philosophy cannot point its finger to a single instance

of the abnormal. The "Antediluvian" and "Pre-Adamite monsters," of which we occasionally hear, are the mere creations of the platform orator, who would rather excite the marvellous for the chance of a little applause, than appeal to the reason of his audience by a simple statement of the truth as it occurs in nature. And yet, after all, the works of God are in themselves sufficiently wondrous to arrest the attention, and never more so than when arranged in that simplicity and perfection of design which it is the aim of legitimate science to detect, and the pride of the philosopher to explain.

In treating, then, of the Extinct Life of the globe, it shall be our aim to assimilate its forms, as far as the facts will permit, with those still living around us; to assign to them their places in the scale of being; to note their incomings and outgoings in point of time; and, above all, to discover their functions in the great economy of nature. Important as facts and specific distinctions are to the botanist and zoologist, the discovery of the functions and ultimate design of being is, to our apprehension, a more exalted pursuit; so true is it (in the impressive words of Coleridge) that "a man may be a chaos of facts, and yet lack the knowledge that God is a God of order." As the establishment of Law appears to be the highest effort of creative energy, so the expression of that law must ever constitute the noblest attainment of created intelligence. And this law is operating everywhere. The force that directs the drifting of a grain of sand is as fixed as that which guides the revolution of a planet; the tiniest blade of grass that turns itself to the sun is but obeying the same law that regulates the growth of the lordliest oak; and the monad, invisible to the naked eye, is the creature of instincts and appetites as imperative as those that impel the actions of man. Nay, not a shower that falls, nor a breeze that blows

-fickle and uncertain as these may seem-but is the result, immediate and remote, of Law, could we only grasp the multifarious conditions that are connected with its production. In tracing, then, the Flora and Fauna of successive epochs, as far as the limits of a popular sketch will permit, we can only indicate a few of their more prominent features and the laws that seem to bear on their development; and yet, restricted as these limits are, enough, we trust, will be indicated to arrest the attention and to arouse the interest in the further prosecution of a subject that stands second to none on the roll of human acquirements. And, after all, it is better to be imbued with the right spirit of research, and to be impressed with the conviction. of the universality and uniformity of natural law, than to have the mind bewildered with details which it cannot connect, and for whose occurrence in nature it is altogether unable to render a reason.

And, first, we enter on what has been termed the PALEOZOIC or "Ancient-Life" period of the world—a period embracing the Silurian, Devonian, Carboniferous, and Permian formations, and characterised, as far as geological evidence goes, by the almost total absence of a dicotyledonous flora, by a preponderance of invertebrate life, and by the general absence of the higher vertebrata, as reptiles, birds, and mammals. The lowest in rank seem the earliest in time; and so in this primeval epoch, cryptogams and cold-blooded water-breathers become the leading manifestations of vitality. The strata lying beneath the Palæozoic (as will be seen by a reference to the Geological Record) have been termed the Azoic or "void of life;" but, more correctly and philosophically, the HYPOZOIC, which merely indicates their position "beneath" the fossiliferous strata, and that without asserting them to be wholly desti

tute of organic remains. So far as our present purpose is concerned, it matters little which term is adopted, so long as we bear in mind that up to the present day they have yielded no traces of life, and are to all intents and purposes truly Azoic. That the Crystalline or Metamorphic strata, termed clay-slate, mica-schist, and gneiss, were at one time the clayey, sandy, and limy deposits of seas and estuaries, is at once admitted by every competent geologist; and that if these seas contained life, those strata must have imbedded its remains. But then, these deposits have, since their solidification into rock, been subjected to thermal, chemical, electrical, and other agencies, to such a degree that they have been converted, or metamorphosed, into crystalline masses, and every trace of life has been obliterated from their structure. No doubt it has been ingeniously suggested that the occurrence in metamorphic rocks of sulphuret of iron, of phosphate of lime, bituminous springs, and other similar products, gives evidence of the presence of organic bodies, through the medium of whose decay such compounds were eliminated. On the other hand, experimentalists equally ingenious have assigned to these products a purely chemical origin; and, even if they could not, the geologist would be little aided by a contrary hypothesis, so long as he had no trace of organic form or texture to guide him in his deductions.

To the paleontologist, therefore, the CAMBRIAN period, with its obscure and scattered zoophytes, trilobites, and shells, becomes the so-called "Dawn of Life." He knows of nothing beyond this primordial zone, and the spirit of true philosophy forbids him to substitute conjecture for fact, or hypothesis for reality. It may gratify the cosmogonist to fashion a glowing globe by the condensation of nebular masses, to cool by radiation a solid crust on the glowing orb, and, after ages of chaotic confusion, to plant