What, then, is the ordinary idea of 'geological time' in the minds of people like my good friend who refused to discuss with me the exact antiquity of the Atlantosaurian? They think of it all as immediate and contemporaneous, a vast panorama of innumerable ages being all crammed for them on to a single mental sheet, in which the dodo and the moa hob-an'-nob amicably with the pterodactyl and the ammonite; in which the tertiary megatherium goes cheek by jowl with the secondary deinosaurs and the primary trilobites; in which the huge herbivores of the Paris Basin are supposed to have browsed beneath the gigantic club-mosses of the Carboniferous period, and to have been successfully hunted by the great marine lizards and flying dragons of the Jurassic Epoch. Such a picture is really just as absurd, or, to speak more correctly, a thousand times absurder, than if one were to speak of those grand old times when Homer and Virgil smoked their pipes together in the Mermaid Tavern, while Shakespeare and Molière, crowned with summer roses, sipped their Falernian at their ease beneath the whispering palmwoods of the Nevsky Prospect, and discussed the details of the play they were to produce to-morrow in the crowded Colosseum, on the occasion of Napoleon's reception at Memphis by his victorious brother emperors, Ramses and Sardanapalus. This is not, as the inexperienced reader may at first sight imagine, a literal transcript from one of the glowing descriptions that crowd the beautiful pages of Ouida; it is a faint attempt to parallel in the brief moment of historical time the glaring anachronisms perpetually committed as regards the vast lapse of geological chronology even by well-informed and intelligent people.
We must remember, then, that in dealing with geological time we are dealing with a positively awe-inspiring and unimaginable series of æons, each of which occupied its own enormous and incalculable epoch, and each of which saw the dawn, the rise, the culmination, and the downfall of innumerable types of plant and animal. On the cosmic clock, by whose pendulum alone we can faintly measure the dim ages behind us, the brief lapse of historical time, from the earliest of Egyptian dynasties to the events narrated in this evening's Pall Mall, is less than a second, less than a unit, less than the smallest item by which we can possibly guide our blind calculations. To a geologist the temples of Karnak and the New Law Courts would be absolutely contemporaneous; he has no means by which he could discriminate in date between a scarabæus of Thothmes, a denarius of Antonine, and a bronze farthing of her Most Gracious Majesty Queen Victoria. Competent authorities have shown good grounds for believing that the Glacial Epoch ended about 80,000 years ago; and everything that has happened since the Glacial Epoch is, from the geological point of view, described as 'recent.' A shell embedded in a clay cliff sixty or seventy thousand years ago, while short and swarthy Mongoloids still dwelt undisturbed in Britain, ages before the irruption of the 'Ancient Britons' of our inadequate school-books, is, in the eyes of geologists generally, still regarded as purely modern.
But behind that indivisible moment of recent time, that eighty thousand years which coincides in part with the fraction of a single swing of the cosmical pendulum, there lie hours, and days, and weeks, and months, and years, and centuries, and ages of an infinite, an illimitable, an inconceivable past, whose vast divisions unfold themselves slowly, one beyond the other, to our aching vision in the half-deciphered pages of the geological record. Before the Glacial Epoch there comes the Pliocene, immeasurably longer than the whole expanse of recent time; and before that again the still longer Miocene, and then the Eocene, immeasurably longer than all the others put together. These three make up in their sum the Tertiary period, which entire period can hardly have occupied more time in its passage than a single division of the Secondary, such as the Cretaceous, or the Oolite, or the Triassic; and the Secondary period, once more, though itself of positively appalling duration, seems but a patch (to use the expressive modernism) upon the unthinkable and unrealisable vastness of the endless successive Primary æons. So that in the end we can only say, like Michael Scott's mystic head, 'Time was, Time is, Time will be.' The time we know affords us no measure at all for even the nearest and briefest epochs of the time we know not; and the time we know not seems to demand still vaster and more inexpressible figures as we pry back curiously, with wondering eyes, into its dimmest and earliest recesses.
These efforts to realise the unrealisable make one's head swim; let us hark back once more from cosmical time to the puny bigness of our earthly animals, living or extinct.
If we look at the whole of our existing fauna, marine and terrestrial, we shall soon see that we could bring together at the present moment a very goodly collection of extant monsters, most parlous monsters, too, each about as fairly big in its own kind as almost anything that has ever preceded it. Every age has its own specialité in the way of bigness; in one epoch it is the lizards that take suddenly to developing overgrown creatures, the monarchs of creation in their little day; in another, it is the fishes that blossom out unexpectedly into Titanic proportions; in a third, it is the sloths or the proboscideans that wax fat and kick with gigantic members; in a fourth, it may be the birds or the men that are destined to evolve with future ages into veritable rocs or purely realistic Gargantuas or Brobdingnagians. The present period is most undoubtedly the period of the cetaceans; and the future geologist who goes hunting for dry bones among the ooze of the Atlantic, now known to us only by the scanty dredgings of our 'Alerts' and 'Challengers,' but then upheaved into snow-clad Alps or vine-covered Apennines, will doubtless stand aghast at the huge skeletons of our whales and our razorbacks, and will mutter to himself in awe-struck astonishment, in the exact words of my friend at South Kensington, 'Things used all to be so very big in those days, usedn't they?'
Now, the fact as to the comparative size of our own cetaceans and of 'geological' animals is just this. The Atlantosaurus of the Western American Jurassic beds, a great erect lizard, is the very largest creature ever known to have inhabited this sublunary sphere. His entire length is supposed to have reached about a hundred feet (for no complete skeleton has ever been discovered), while in stature he appears to have stood some thirty feet high, or over. In any case, he was undoubtedly a very big animal indeed, for his thigh-bone alone measures eight feet, or two feet taller than that glory of contemporary civilisation, a British Grenadier. This, of course, implies a very decent total of height and size; but our own sperm whale frequently attains a good length of seventy feet, while the rorquals often run up to eighty, ninety, and even a hundred feet. We are thus fairly entitled to say that we have at least one species of animal now living which, occasionally at any rate, equals in size the very biggest and most colossal form known inferentially to geological science. Indeed when we consider the extraordinary compactness and rotundity of the modern cetaceans, as compared with the tall limbs and straggling skeleton of the huge Jurassic deinosaurs, I am inclined to believe that the tonnage of a decent modern rorqual must positively exceed that of the gigantic Atlantosaurus, the great lizard of the west, in propria persona. I doubt, in short, whether even the solid thigh-bone of the deinosaur could ever have supported the prodigious weight of a full-grown family razor-back whale. The mental picture of these unwieldy monsters hopping casually about, like Alice's Gryphon in Tenniel's famous sketch, or like that still more parlous brute, the chortling Jabberwock, must be left to the vivid imagination of the courteous reader, who may fill in the details for himself as well as he is able.
If we turn from the particular comparison of selected specimens (always an unfair method of judging) to the general aspect of our contemporary fauna, I venture confidently to claim for our own existing human period as fine a collection of big animals as any other ever exhibited on this planet by any one single rival epoch. Of course, if you are going to lump all the extinct monsters and horrors into one imaginary unified fauna, regardless of anachronisms, I have nothing more to say to you; I will candidly admit that there were more great men in all previous generations put together, from Homer to Dickens, from Agamemnon to Wellington, than there are now existing in this last quarter of our really very respectable nineteenth century. But if you compare honestly age with age, one at a time, I fearlessly maintain that, so far from there being any falling off in the average bigness of things generally in these latter days, there are more big things now living than there ever were in any one single epoch, even of much longer duration than the 'recent' period.
I suppose we may fairly say, from the evidence before us, that there have been two Augustan Ages of big animals in the history of our earth—the Jurassic period, which was the zenith of the reptilian type, and the Pliocene, which was the zenith of the colossal terrestrial tertiary mammals. I say on purpose, 'from the evidence before us,' because, as I shall go on to explain hereafter, I do not myself believe that any one age has much surpassed another in the general size of its fauna, since the Permian Epoch at least; and where we do not get geological evidence of the existence of big animals in any particular deposit, we may take it for granted, I think, that that deposit was laid down under conditions unfavourable to the preservation of the remains of large species. For example, the sediment now being accumulated at the bottom of the Caspian cannot possibly contain the bones of any creature much larger than the Caspian seal, because there are no big species there swimming; and yet that fact does not negative the existence in other places of whales, elephants, giraffes, buffaloes, and hippopotami. Nevertheless, we can only go upon the facts before us; and if we compare our existing fauna with the fauna of Jurassic and Pliocene times, we shall at any rate be putting it to the test of the severest competition that lies within our power under the actual circumstances.
In the Jurassic age there were undoubtedly a great many very big reptiles. 'A monstrous eft was of old the lord and master of earth: For him did his high sun flame and his river billowing ran: And he felt himself in his pride to be nature's crowning race.' There was the ichthyosaurus, a fishlike marine lizard, familiar to us all from a thousand reconstructions, with his long thin body, his strong flippers, his stumpy neck, and his huge pair of staring goggle eyes. The ichthyosaurus was certainly a most unpleasant creature to meet alone in a narrow strait on a dark night; but if it comes to actual measurement, the very biggest ichthyosaurian skeleton ever unearthed does not exceed twenty-five feet from snout to tail. Now, this is an extremely decent size for a reptile, as reptiles go; for the crocodile and alligator, the two biggest existing lizards, seldom attain an extreme length of sixteen feet. But there are other reptiles now living that easily beat the ichthyosaurus, such, for example, as the larger pythons or rock-snakes, which not infrequently reach to thirty feet, and measure round the waist as much as a London alderman of the noblest proportions. Of course, other Jurassic saurians easily beat this simple record. Our British Megalosaurus only extended twenty-five feet in length, and carried weight not exceeding three tons; but, his rival Ceteosaurus stood ten feet high, and measured fifty feet from the tip of his snout to the end of his tail; while the dimensions of Titanosaurus may be briefly described as sixty feet by thirty, and those of Atlantosaurus as one hundred by thirty-two. Viewed as reptiles, we have certainly nothing at all to come up to these; but our cetaceans, as a group, show an assemblage of species which could very favourably compete with the whole lot of Jurassic saurians at any cattle show. Indeed, if it came to tonnage, I believe a good blubbery right-whale could easily give points to any deinosaur that ever moved upon oolitic continents.
The great mammals of the Pliocene age, again, such as the deinotherium and the mastodon, were also, in their way, very big things in livestock; but they scarcely exceeded the modern elephant, and by no means came near the modern whales. A few colossal ruminants of the same period could have held their own well against our existing giraffes, elks, and buffaloes; but, taking the group as a group, I don't think there is any reason to believe that it beat in general aspect the living fauna of this present age.