The divergence of opinion between scientific and unscientific persons is scarcely anywhere more conspicuous than in their measurements of the age of the world we live in. A popular impression still prevails that the old beldame earth, as Hotspur calls it, is about six thousand years of age. A little margin is sometimes allowed. By an exercise of heroic liberality a period of ten or twelve thousand years is occasionally conceded for the earth’s existence. Any chronology discontented with these ample limits comes within the domain of rash and dangerous speculation. Some, indeed, who would fain conciliate all parties, are willing to extend the bounds on certain conditions. They will grant a large extra slice of time, provided that during that period the earth was a shapeless uninhabited lump, or if inhabited, not inhabited by men. ‘Come, now,’ says the cheap-jack, ‘I’ll tell you what I’ll do with you; I’ll throw you in another five thousand years; fifteen thousand years! and take the lot. What! not do? I’ll make it twenty thousand. Now, I’ll tell you what I’ll do with you: I’ll make it five-and-twenty thousand years, and if that won’t satisfy you, you aren’t worth arguing with.’

What scientific men think of the cheap-jack’s offer it is the object of this essay to consider.

The problem upon which many thoughts and speculations of science are for the moment converging is the origin of life. There are some who believe that under certain chemical conditions living creatures are continually coming into existence, ungenerated by any living parent, born as it were without birth, acquiring an animated existence, with powers of motion, feeding, and reproduction, from substances previously wanting in one or all of these capacities; such creatures, in short, as, if asked for their parentage, could but answer, each for itself, my father was an atom, and my mother a molecule. It should be remembered that the little animals supposed to arise in the manner described first become visible, if at all, as the tiniest objects that microscopes can detect. But whether there is or is not in these days a continual coming into existence of these infinitesimal pigmies, they are just such productions as the Theory of Development would suppose to have arisen originally, constituting the first outburst of life upon the globe, ancestral to the noblest forms of animated nature now extant, progenitors in an unbroken line of man himself. As a rule, among living things we find that offspring bear a tolerably exact resemblance to their parents. The lower the organism the less easy is it to distinguish specimens of one generation from those of another; and even in the most highly organized creatures the points of resemblance generally far outweigh the points of difference between the parents and their children. In short, under ordinary circumstances, not one generation only, but a hundred, may pass away without registering any perceptible alteration in the character of a species. A hundred generations of mankind would require a period of about three thousand years. A hundred generations of less important creatures might not perhaps require even as large a number of hours. But between the two extremes the necessary periods would bear a kind of ratio to the perfection of the organism. Variations might now and then follow one another in quick succession, and then a pause come of a thousand generations or so before any further changes in the character of a species.

Such are the conditions under which Mr. Darwin and his followers believe it possible for the whole sequence of changes to have been effected, which have ended in peopling the whole earth with a countless variety of the most diverse forms of life. Many persons are horrified at the notion of linking together a man and a monkey even by the most distant ties of consanguinity; what will they say to a genealogy which begins with an almost invisible speck and ends with a Patagonian giant—a genealogy which asserts that, through the slow process of minute changes occurring for the most part at rare intervals, our fair humanity has been developed or evolved out of creatures which no unaided human eye could distinguish from the dust on which we carelessly trample. To some ears such a theory must sound wild and preposterous beyond all the boundaries of sane and rational thinking. And, in truth, no censure could be too severe, no ridicule too keen for so extravagant a piece of folly as this theory must be, if the old and still prevailing notions about the age of the world have any foundation in fact. It only begins to be reasonable, if we can afford to stretch our notions of history from the narrow margin of six thousand to the broader field of six hundred thousand years, with an indefinite past in the background.

This vast lapse of time, as commensurate with the existence of the inhabited globe, is essential to the Theory of Development. It must be established, as it has been, by independent evidence of its own, before it can give to that theory its absolutely necessary support. But the Theory of Development in its turn helps the mind to believe and realize this enormous lapse of time, with its seemingly never-ending march and flow, rank upon rank, wave upon wave, by finding work and employment for all its almost measureless duration. It explains, as it were, why the drama of life still goes on, why the play was not long ago played out, and the curtain let fall upon all the busy multitudinous actors.

Time of itself does nothing; but nothing can be done without time. It is not a personal agent, but a necessary condition. We cannot even think, much less reason, of things as occurring out of time and independently of it, any more than we can think or reason of matter as existing independent of space. Every occurrence takes time: and yet we may not leap from this fact to the conclusion that a countless multitude of occurrences will require a vast duration of time. Professor Tyndal, in his Lecture on the Scientific Use of the Imagination, refers to waves of light less than 1/50000 of an inch in length. How many do you suppose of such waves would be required to compass a mile? How many to accomplish the 185,000 miles which light travels in a second? Each undulation is a separate occurrence, so that we have millions of millions of occurrences following one upon another in a second of time. In studying, therefore, the complete fabric of the globe, or even of the whole material universe as far as it comes within our ken, the problem for solution is not whether these great results could or could not have been brought to pass in an indefinitely short space of time, in the twinkling of an eye, as one might say, but whether the space of time employed in their production has actually and in fact been indefinitely short or indefinitely long. We ought also to bear in mind that the terms we use when we speak of long and short, are relative not absolute—relative to the duration of our own lives, or to some other arbitrary standard which we are pleased to set up for purposes of comparison. Thus a year is long compared with a minute, but short compared with a millennium; a thousand years would be an enormous length for the life of a mortal man, but compared with the ceaseless flow of ages, which we call eternity, this same thousand years becomes, as it were, an imperceptible speck, less than a drop of water compared to the Atlantic, a point of time so inconceivably minute, that no human mind could grasp it as an intelligible unit of measurement. For time, we have an inexhaustible past on which to draw. Against any given theory of production, no objection pure and simple that the theory makes too large a demand upon time, can be maintained. An objection, to be valid against the existence of life on the earth a million of years back, must postulate that there was no earth then in existence, or none capable of supporting life; for if we choose to stand by the doctrine of final causes, life upon the earth must have begun as soon as life upon the earth was possible, otherwise we should have a fair and perfect design with its purpose unaccomplished; or, if we prefer the Theory of Development carried out to its legitimate consequences, equally must we admit, that as soon as the earth was fitted for living creatures, living creatures would be generated upon it.

In tracing back the duration of the globe, the first demand of the uninitiated will be for the written evidence of historical records. The popular impression claims to be founded upon such evidence of the most authoritative description. Little do the upholders of this impression in general understand that they are building their faith, not upon the Book of Genesis, or the inspiration of the Hebrew lawgiver, but on the arithmetical speculations of an Irish archbishop, who lived in the seventeenth century.

Before we can accept the Hebrew genealogies as competent data for historical chronology, we must understand the principles on which they were framed. In ancient languages we have abundant evidence to show that the ties of blood were not as sharply distinguished as among ourselves. The same word sufficed to designate son and grandson, and even the most remote descendant. A man’s heir was called his son; an usurping successor might receive the same title43; and, beyond all this, it has been shown to have been ‘a common practice with the Jews to distribute genealogies into divisions, each containing some favourite or mystical number; and that, in order to do this, generations were either repeated or left out.’ Some persons, perhaps, will say, ‘We don’t believe it, or we don’t believe it in regard to any of the biblical genealogies.’ And yet the very first chapter of the New Testament is the most conclusive and incontrovertible proof of the statement; for our Lord’s genealogy44 is there expressly divided into three periods of fourteen generations each, and the middle period has been stripped of three generations in order to bring it down to the pre-determined number. The names of three well-known princes (Ahaziah, Joash, Amaziah), whose histories occupy several chapters in the Second Book of Kings, are omitted, and Amaziah’s son is described, without further note or comment, as a son begotten by one who was really his father’s great-grandfather. In a matter so obvious, there cannot attach to the compiler of the genealogy the very faintest suspicion of bad faith. He was following the custom of his country, for reasons then deemed, and perhaps in those days actually being, good and sufficient. Can we make as satisfactory an apology for men in the present day, who shut their eyes to the nature of the evidence on which they build opinions about the age of the world opposed to the discoveries of science? If in the first century of the Christian era, in times of comparative enlightenment, by men of approved truth and uprightness, genealogies could be compiled without the smallest regard being paid to the actual number of successive generations, it becomes impossible to attach any value as chronological evidence to Hebrew genealogies fifteen hundred, or, for all that we can tell, fifteen thousand years more ancient. Had the genealogy on which this conclusion rests admitted a chance of error, had there been any motive for fraud in its construction, did any suspicion lie against its authenticity, the case would be weakened. But just because there neither was nor could have been error in the mind of the writer, or deceit in his intention, just because what he wrote, he wrote deliberately and of set purpose, it is certain that his record is not, and was never meant to be, a measure of time; and that those who persist in measuring time by similar records, are the victims of a manifest delusion, ensnared, it may be feared in too many cases, with their eyes open.

There is an old jest that, in the pride of antiquity, a Welshman generally traces back his lineage not only as far as Adam, but a great deal further. Nothing was easier, before the age of historical criticism, than for men or nations, whose real origin was lost in obscurity, to link their names to an illustrious past. Nothing was easier than to develope the obscurity itself into a long line of remote ancestors, whose names and virtues could be invented and multiplied at pleasure. What the poet was only too willing to imagine, the mathematician seemed able to confirm, by registering astronomical occurrences in far-distant long-past ages with as much precision as those which he predicted, and predicted truly, for his own and future times. The Hindoo chronology reckons the age of the world by millions of years. The Egyptians twenty centuries ago used to tell of 330 kings of whom they knew no more than the names. There were Greeks who claimed to be older than the moon; others who anticipated the theory of abiogenesis by claiming to be sprung from the earth itself without the intervention of parents; and yet others, who with more modesty or more pride, as we please to regard it, derived their origin from gods and demigods. None were willing to be thought new people. The man of yesterday, the novus homo, the upstart, the parvenu, has ever been disliked and laughed at by society. And in like manner, among nations, a new rival excites the fears and encounters the ridicule of the established clique. Claims to antiquity, therefore, were as advantageous to possess as they were easy to forge. Those that have been mentioned, being unattested by any corroborative facts, and, where they are not obviously false, being unsusceptible of proof, are worthless in themselves. One thing they tend to show, namely, that all remembrance of the real origin of mankind, and of the date of that origin, had been absolutely lost to those ancient peoples. From over the sea, from beyond the mountains, from the bright east or the frozen north, they might know that their forefathers had made pilgrimage in distant ages—or they might know of no time, however far back, when the seat of their habitation had not been occupied by their own progenitors. In either case their ignorance of primeval history is as absolute as it is conspicuous. One prevailing tradition, it is true, is current alike in sacred and profane literature, of a far-off golden time, an age of simplicity, when man conversed with the beasts of the field, when the earth brought forth her fruits spontaneously, with her bosom as yet unvexed by the ploughshare, ere the knowledge or the discrimination of good and evil had come into the world—the record, in one word, as all these details tend to prove, of a time before man had become a moral being; a dim mysterious recollection, almost like a dream, of a time before the animal nature had been decisively exalted into humanity. Some persons believe, against all probability of evidence, that spoken language was a sudden original inspiration instead of a gradual invention. None, however, assert the right of believing the same thing in regard to letters or written language. The progressive origin of alphabetical signs is admitted on all sides, so that there must have been a time when man had to trust to his fallible memory instead of written memoranda. The growth of picture-writing itself must have been extremely slow, from the difficulty of establishing an agreement as to the meaning of particular representations. What this difficulty amounts to may to some extent be tested any day in a picture-gallery, where all the appliances and skill of modern art are at our service. Without the aid of a descriptive catalogue, it is but seldom that any two accounts of the meaning of the same picture would be found to agree. The art of drawing, it may well be supposed, was not an inspiration. It had to be invented. The very idea of transmitting a record to future ages would only occur with the advance of civilization. The crumbling surface of the rock, the decaying bark of trees, would be the first perishable and soon obliterated manuscripts. Before account could be taken of months and years, astronomy must have made some progress. Before the flow of centuries could be accurately noted, arithmetic must have advanced far beyond the stage at which we still find it among numerous savage nations. An Esquimaux couple, it is said, find it difficult to count their own children, even when they are no more than four or five45.

From these considerations alone we may feel perfectly certain that numbers of ages elapsed before men acquired the means of recording the duration of time by any definite measurements. Unconsciously and without set purpose, perhaps the very earliest tribes and the most untutored have left behind them traces not only of their existence but of the date and era at which they lived; traces which we are only now beginning to decipher, and to read with faltering lips.

All around us in England, in Devonshire, in Torquay, and all over the globe, lie the memorials of human beings, of whose day and generation the oldest historical records we possess know absolutely nothing. Here and there the tale is told by a heap of shells. From such heaps we know what dishes were served at the Dane’s dinner-table, at a time when cereal crops were unknown in Denmark, and sea-weed was used instead of salt46. Oysters and cockles, mussels and periwinkles, seem to have been ad libitum; the stag, the roe-deer, and the wild boar were at the service of that ancient Dane as often as he could catch them with his weapons of wood, stone, horn, or bone47; when pork and venison were scarce, his palate could content itself with dog or fox. From the waters of the mountain-lake, from the centre of the high-piled barrow, in the circles of giant stones upon broad-stretching plain or wild moorland, from peat-moss and railway-cutting and limestone cavern, we obtain, as Sir John Lubbock and Mr. Pengelly and others have so well shown, the unwritten records of prehistoric man, of human beings unnoticed in any credible history, and preceding all well-established definite historical dates whether of sacred or profane literature. Who reared the Titanic monuments of Stonehenge and Abury we know not. We know not who constructed the extraordinary animal-mounds of Wisconsin in North America—mounds hundreds of feet long, reared a few feet above the level plains, in the figures of men and beasts and birds and reptiles. These monuments, if such they were intended to be, must have demanded prodigious industry for their construction. They imply a considerable population, and some advance in artistic skill. But why they were designed, and who designed them, are circumstances alike unknown. It is necessary to press home this argument founded upon our ignorance, and to dwell upon it with some emphasis, because numbers of persons are pleased to imagine and assert that, within two or three thousand years before the Christian era, the whole human population of the globe was as it were still in the bud, and that from a single family, not mustering a dozen members to start with, all its tribes have since then been derived, with their endless diversities of features, hair, complexion, customs, tastes, and other qualities both of mind and body. According to the old chronology we are to suppose that within this limited space of time, from under a single roof, the children went forth, spreading over all lands, not only miraculously forgetting the common ancestral language, but forgetting the arts, the traditions, the sentiments, which they had in common, retrograding in some cases into a savage ferocity or an almost imbecile simplicity, in others retaining or developing forms of an advanced civilization. Esquimaux and Hottentots, Japanese and Red Indians, the Negro and the Greek, are thus united in ties of cousinship by no means remote. Arts, monuments, and modes of life essentially different in spirit and character are supposed, within these narrow bounds of time, to have sprung up; nor only to have sprung up, but to have passed away, leaving only a few faint vestiges to recall the artists, the heroes, the lawgivers, the national temper, the genius of the time, whereunto they owed their existence. It must surely be allowed that marriage customs change with slow reluctance; an alteration of the sentiment with which women are regarded is not easily or quickly produced. Yet on no subject are the practices and opinions of mankind more widely diversified. One wife to one husband is in some places the rule; but in others, one husband to many wives, one wife to many husbands, or husbands and wives without any special appropriation, which some societies consider a selfish infringement of the general right. According to the customs of different nations, wives must be fought for, or stolen, or purchased, or caught in a race, or wooed and won with pin-money and other endearments. According to the feeling of different races, the wife is a chattel, a beast of burden, a slave, a stewardess, a domestic ornament, an equal, or a master48. Let it be granted that many of these customs and sentiments may have been contemporaneous in their growth or development, the same thing cannot be admitted of the different centres of colonization in which they grew and developed. Men do not without cause quit their ancestral homes to found colonies in remote parts of the world; and the causes only arise at intervals. When the cause has arisen, and the new settlement been occupied, the exiles retain for the most part, and long retain in affectionate remembrance the manners and customs, the religion and laws, of the mother-country; or when the remembrance is other than affectionate, they retain them from the want of an alternative, from the conservatism in which all men to a greater or less degree participate, from the incapacity of the human mind to strike out new customs, or revolutionize ideas, except by a gradual and half-unconscious progression.

Among the visible and tangible proofs of man’s and the earth’s antiquity, few are more interesting than those presented in the section, well known to geologists, cut by the railway through the delta of the TiniÈre, a torrent flowing into the Lake of Geneva49. Three layers of vegetable soil appear in the section, at depths of four and ten and nineteen feet respectively below the present surface. These layers contained distinctive relics. In the first were found ‘Roman tiles and a coin,’ in the second ‘fragments of unvarnished pottery, and a pair of tweezers in bronze;’ in the third, ‘fragments of rude pottery, pieces of charcoal, broken bones, and a human skeleton having a small, round, and very thick skull.’ The thick-headed owner of that skull is computed to have lived, at the lowest estimate, about five thousand years ago. But the cone of the delta began to be formed long before the man was buried in it, and higher up the stream another cone is found about twelve times as large, requiring therefore a time for its formation about twelve times as long, unless we have recourse to that miserable refuge for the destitute in argument, which consists in supposing that causes now slow and comparatively regular, operated in former times with an incomparably greater speed and a more spasmodic violence, of which no trace remains, nor likelihood appears in the record. In a word, we may infer that, so far from the shapely order and decorous arrangement of the earth’s surface being only six thousand years old, it has taken no less than fifty or a hundred thousand years to pile up this one little heap of mud and gravel. The age of human works buried under the fertilizing sediment of the stately Nile is much disputed, but there can be little doubt, if we take into consideration the ancient fluviatile deposits in terraces sometimes hundreds of feet above the present alluvial plain, that the long-unknown sources of the mysterious river have produced ten myriad repetitions of the annual overflow, pouring down its waters to the sea through a thousand centuries.50

But Egypt and Switzerland are a long way off; geologizing in a railway-cutting has been before now a fatal employment; and digging pits forty feet deep into the mud of the Nile is an operation attended with difficulties peculiar to itself. Here, however, in Torquay, close at hand, we possess a register of time as compact, as accessible, as genuine, as the Library of the British Museum. Limestone, it is well known, is formed beneath the waters of the sea. When it appears above the sea-level, it must have been upheaved from its ocean-bed. How long a period must be allowed for the hill which contains Kent’s cavern to have been formed by this double process, may be left for the present to the imagination. How long a time elapsed before the cavern was burst open or eaten out from the solid limestone, we will not enquire. Thanks to the diligent exploration of it; thanks to the unwearied courtesy of its scientific curators51, the contents of the cavern, or at least a portion of them, are now well known. Not only do they embrace the remains of animals not now existing in England, but they embrace the remains of animals long since lost to the globe. With these are mingled the products of human intelligence, the weapons of the savage. The cave-earth which, as well as the stalagmite, contains these relics of a most remote antiquity, is itself permeated with films of stalagmite, a conclusive proof of its gradual introduction. Over the lower portions have been formed in succession three solid stalagmitic floors, remnants of which have quite lately been discovered still imbedded in the cavern52. Let us for a moment consider what this implies. If we transport ourselves to Matlock Bath in Derbyshire, for the small fee of a penny, any one of its ‘petrifying wells’53 will be open to our inspection. In these curious grottoes whatever object you please, natural or artificial, be it skull or the cap that once covered it, be it basket or bird, or shell or leaf, may be encrusted with a coating of stalagmite. The inexperienced visitor would like to place an object in the well, and to wait while the ‘petrifying’ waters do their work. He is surprised to find that in that case he must wait and watch for months and years, while the slow persevering stream falls upon his treasure with its ceaseless drip, drip, drip, and that the work so slowly accomplished would not be accomplished at all if the flowing of the stream were hastened. Imagine, then, in this famous cavern of ours what an interminable song, though an intermittent one, must have been sung with this drip, drip, drip, through ages and ages, to produce, as in one place it has done, a solid stalagmitic mass full twelve feet in thickness. Now, according to Usher’s chronology, we have seventeen centuries from Adam to the Flood, and twenty-three centuries from the Flood to the age of Julius CÆsar. If this chronology is to be accepted, Kent’s cavern must have been filled either in the first period or in the second. As the same arguments will apply to each, let us assume that the second or longer period sufficed for this purpose, and see what further admissions this assumption will involve. We have three and twenty centuries at our disposal. At the end of that time we know historically that Britain was occupied by tribes more or less savage, some of them going about almost naked, destitute of almost all the arts of civilization. We are to imagine the ancestors of this wild race migrating from Asia and slowly pioneering their way to the western limits of Europe. Necessity is the mother of invention; but these men in their difficult adventurous travel through unknown seas and pathless jungles tenanted by dangerous beasts, learn only how to forget. They forget the use of brass and iron, and take to weapons and tools of flint; they give up tillage; they give up building strong towers, and shelter themselves in wooden huts or caves and dens of the earth. The climate of Western Asia is warm and sunny, that of England often, and in many parts, bleak and foggy and cold; therefore these intelligent children of Noah, in order perhaps to harden themselves in the process of acclimatization, as they force their way into the fog and mist, instead of keeping or assuming the flowing robes of the Asiatic, exchange their garments, at any rate in battle, for a wash of paint. How interesting it would be to have the family portraits of a Highland clan from the earliest times, showing how they gradually made it fashionable to do without the various articles of clothing which one by one they have been induced to resume54! During the same epoch, within the same limits of time, migrating also from the warm regions of Asia, came elephants and lions, hyenas and bears, the rhinoceros and the elk. Little recked they then of change of climate, which now they so ill endure. They prowled all over Europe; they swam across the English Channel. Yet before the historical period begins in Gaul and Britain, most of these species had had time not only to make their way thither, not only to nourish and abound in these habitations, but to die out and to be forgotten. We know for certain that elephants once roamed over Devon. Did they succumb to the flint weapons of the savage? Was the same savage able to extirpate the hyena and the lion, though the representatives of those fierce beasts still partially set us at defiance in India, notwithstanding the rifles and gunpowder of modern civilization? Let us imagine that within the specified time all that has been mentioned could have happened, and that some of the animals, such as the woolly rhinoceros, had time to assume the characters of northern species, or that the climate had time for vast changes and alterations, or that the winds perhaps in those days blew hot and cold with the same breath so as to suit arctic and tropical species indifferently;—we must imagine further that within the same limits the three floors of stalagmite could have been formed in succession, and two of them successively broken up. They must have been formed, not during the whole of the period, but only during that part of it which followed the introduction into Britain of wild beasts, and of men who used flint weapons; for one unmistakeable weapon of human manufacture, and innumerable bones of the great old cave bear have been found within the rock-like breccia of stone and stalagmite and cave-earth, some feet below both the floors of more recent formation55. The longer the period, therefore, we allow for the migration from the East and the dying out of civilized life, the shorter is the period left for the stalagmitic formation. Yet probably the whole twenty-three centuries would not suffice for the formation of one of the floors; how much less could a fraction of the period suffice to form all three, and to supply the intervals during which, through some change of circumstances, the cave-earth was accumulating, and consequently no solid floor being formed.

At Matlock the drip is continuous, being supplied by a stream, and not being, as in Kent’s cavern, dependent on the chances of the rainfall and the quantity of water that may percolate through a limestone roof. At Matlock, for purposes of trade, it is an object that a coating of stalagmite should be formed as quickly as possible. With this view the water is allowed to fall at the rate of fifty or sixty drops a minute, the drip being maintained at numerous points simultaneously. At Matlock we may roughly estimate that an inch of stalagmite would require four years for its formation, so that twelve feet and a half would require six hundred years. In Kent’s cavern, on the other hand, the drip is often interrupted. There is no commercial interest at hand to regulate the speed in the most advantageous manner, so that it falls sometimes too quickly and sometimes too slowly. The points at which it falls are few and far between. It cannot reasonably be supposed in any year to produce even a twentieth of the effect we have estimated for the drip at Matlock. In other words, the two later floors of the cavern would alone require a period of twelve thousand years for their formation. Even at this rate the cavern would probably have been so extremely damp and uncomfortable that no men or beasts would have chosen it for a shelter in rainy weather.

But the cavern inscriptions make it as certain as can be that the rate of speed here allowed for the formation of stalagmite is vastly too high, and therefore that the time allowed for the formation is vastly too low. The famous inscription of 1688 was shown to me a few days back56. It was at that very time wet with the drip from the cavern roof, a drip falling at the rate of thirty-four drops a minute. If the date were really cut in the year 1688 (and there is no reason to suppose that it was not), by our first calculation more than two inches of stalagmite ought to have formed over it. Instead of which there is but a thin veneer, a veneer that was observed upon it more than forty years ago, and which has not in all those forty years increased enough to make such a description of it inappropriate. If the date 1615 be authentic, over which, in the opinion of the superintendents of the exploration, not one-eighth of an inch of stalagmite has been formed in more than two centuries and a-half, at the same rate of progression twelve feet and a-half of stalagmite would demand for its formation three hundred thousand years.

This cavern by itself, therefore—this one little crack in the outermost rind of the earth’s surface—proves a comparatively immense antiquity for the existence of organic life and of human beings upon the globe. But to compare the antiquity of the cavern contents with the antiquity of the limestone formation in which they are contained is positively beyond any intelligible numerical measurement. Yet the limestone formation itself is filled with the relics of living creatures, and in some parts, if not in all, is one gigantic mass of such remains.

In cliffs of sea-shore and river, in railway-cuttings, in mine-shafts and quarries, we may often see layers of the earth’s crust in the order of their original deposition. Except where the signs are present of some subsequent violent interference, this order is uniform and invariable. It is not that all the members of the series are invariably present, far from it; but in order of deposition the relations of higher and lower are never interchanged. Every one of the many different layers which have been distinguished by geologists has a distinctive group of fossils. You may, if you please, suppose that for each of these layers of the earth’s crust there was a new creation of living creatures, wonderfully like at each successive step, though wonderfully different at long intervals, as though they were the work of an artist whose ideas moved but slowly; but for such a supposition you have no authority; the conception has neither simplicity nor grandeur; it does not even accord with the facts, since, amid the general change of organic structures, we find the permanence of a few; and while the groups of two successive layers have, each of them, numerous distinctive forms, it is impossible to draw any definite boundary-line between the groups themselves, which sometimes intermingle with an inextricable interlacing on their confines. Nothing comes out more clearly to the student of the rocks, than that the world of to-day is the world of millions of years back; from one point of view ever-changing, yet ever essentially the same; from another point of view, out of the utmost regularity of alternation, never producing the same thing, or presenting the same aspect twice. We think that the stage has been essentially altered, because in the days of that immeasurable past we did not strut upon it. We are unable to fathom the depth of our own insignificance, and are unwilling to believe in a march of time, compared with which the span of our own lives seems so contemptible. In the depths of the ocean the formation of chalk is said to be going on at this very day. Probably there is no time known to the geologist at which the formation of chalk has not been going on in the depths of the ocean; but its older layers have been altered by chemical and mechanical forces, by fire, by pressure, and by other means.

We know that chalk and limestone do not form in the open air. If we find them piled up in enormous hills and mountains high above the level of the sea, and far from its coasts, we know that they did not grow in that position; that once their proud crests and ridges lay low in an ocean bed. They could not have been formed on a sudden, or rapidly, or by any other than the slow steps of infinitesimally small successive accumulations: for we find them filled throughout with the evidences of life, shells and sponges, and corals of exquisite beauty and delicacy, generations after generations of which must have had time to build up their beautiful fabrics. Many things may be hastened; you may quicken the growth of many; but you can’t hurry a sponge. Every foot and inch of a chalk cliff, of a limestone mountain, must have been formed originally under water with almost incredible slowness. It must have been raised up to meet the clouds of heaven since its formation in the ocean-depth. Do you think that this can have been a rapid process? Volcanic cones, it is true, are sometimes piled up by a sudden effort. But with widespread platforms of solid rock the upheaving forces deal more respectfully. An average elevation of a foot or two in a century, is perhaps a high exceptional speed for such movements. But this rate requires a thousand centuries for a hill only one or two thousand feet high, to rise, not from the depths, but from the surface of the water. If we had only a single formation to deal with instead of scores of them; if we had a thickness of only one thousand feet of the earth’s crust to consider, instead of scores of thousands, the proved antiquity of the globe would be enormous. What is to be said, then, when we stand face to face with what geologists have been pleased to call the new red sandstone? This formation cannot be less than millions of years old, although in relation to the Devonian limestone it is indisputably new. Those deep red rocks, that with their fantastic profiles in so many places fringe the southern border of Devon, must have been formed since the limestone; for the simple reason, that in every part they are full of pebbles or fragments of the limestone containing characteristic fossils of the earlier formations. It will at least be granted that you cannot break off a piece from a rock before the rock itself exists. Prior, then, to the very beginning of the formation of these red conglomerates, the limestone rock must have been formed; it must have been heaved up above the level of the sea; fragments must have been broken off from it, rolled into pebbles, triturated into sand. As the breaking, and the rolling, and the grinding went on, so with equal steps would the growth of the conglomerate proceed. But the workshop and the work must still have been beneath the waters of the ocean, and not till the whole work of formation was finished could the further process be begun of raising the work above the level of the waves.

It is not uncommon to find fossils in the pebbles of a conglomerate rock showing lines of a dislocating fracture filled with spar. The fossil shell or coral once had an inhabitant. We must allow time for its life and death. Its vacant tabernacle must then have become filled with extraneous matter. This must have required time to harden into rock. While that rock was still in the mass, some cause must have operated to fracture it, and such causes are not of every-day operation. After this, more time was needed to fill up the divisional line with spar; more time to break off the fragment containing the shell from the general mass of the rock; more time to roll it into a pebble; more time to imbed it hard and fast in a conglomerate rock; more time to raise the rock high out of the waters; and, lastly, one more vast addition of time for the crumbling away of the conglomerate formation, so as to expose the tall sea-cliff from which human hands might gather this memorial relic of untold ages. The same tale is told by the coal-measures. Dr. Dawson, of Montreal, has drawn out the argument from the carboniferous formation57 with extraordinary force and a convincing plainness that leaves nothing to be desired, for the benefit of any one who will read his great work on Acadian geology. The formation of coal depends on sub-aËrial growths, affected by sub-aqueous action. The trees and plants, out of which coal is formed, for the most part could not possibly have grown under water. The mud, the sand, the stone which cover seams of coal, could not have been laid over them without the agency of water to bring them down, and spread them out in regular layers of stratification. When the hollow bark of a tall tree is found erect upon its roots, with those roots still permeating the clay from which they once drew nourishment, it is evident that time must be allowed for the growth of the tree, for the almost complete decay which left nothing of it but its bark and roots, and for the slow accumulation of sediment which has encased without overthrowing it. A complete alteration must have taken place in the conditions of the ground in the interval between the time when the tree began to grow, and the time when a length of seven or eight feet of its upright stem was buried in mud. Layers, indeed, of sand and mud may be spread out over small areas by storms and inundations with comparative speed; but if above the sands we come to thicknesses of limestone composed almost entirely of animal remains, such as those of shells and fish, not only are we forced to admit a long period for the successive generations of those creatures, but we are forced to observe the products of the ocean lying actually above the products of the dry land, as though, according to the old poetical extravagance, the stag and doe had taken to the waters and the fishes been building in the tree-tops. The conclusion is inevitable, that what was once dry land, fruitful in vegetation, in process of time became a swamp, and from the swamp became a sea. It will be a fresh surprise, but a fresh evidence of time’s duration, if above the limestone we find more clay with more plants buried in more mud, and over-topped by more limestone. Bearing in mind the old supposition, that order and beauty and life upon the globe are only six thousand years’ old, astonishment should reach its climax when we find, as we do, that within the thickness of only a few feet of the earth’s crust, the record that we have been describing is repeated again and again and again; but beyond the climax, a fresh and overpowering marvel awaits us, when, as at one spot in British America, the record expands itself from a few feet into sixteen thousand, showing conclusively by eighty successive bands of coal that fourscore times at least, and perhaps many more, while that thickness of the earth’s crust was forming, the waters gave place to dry land, and in turn the dry land to the waters,—showing conclusively that during all the period of these changes tall forests of graceful trees abounded on the globe, along with exquisite ferns and curious reptiles, and beetles and winged insects of great size and beauty; while fish replenished the waters, along with an infinity of shells and corals, and other inhabitants of the deep. Yet these sixteen thousand feet, these eighty successive forests, these hundred and sixty changes, comprise but a small fraction of the whole known succession of strata.

It is true that different strata not only may, but must have been forming at one and the same time in different parts of the world. But when one stratum has been formed out of the wreck of another, it is self-evident that they cannot have been formed together. The same thing is obvious in regard to any number of layers found lying in undisturbed succession one above the other. They must have been formed successively, the lowest first, the highest last. But one point about them is far from obvious, namely, the length of the interval that may have intervened between the end of one formation and the beginning of another. The great African desert has been the great African desert as far back as human histories extend; yet in times geologically recent it lay beneath the waters of the ocean. Should it be again submerged before any fertilizing agencies have covered it with signs of its sub-aËrial exposure, another layer of sand may be thrown down upon it, containing new marine fossils, and no memorial be left to the future geologist of the vast era during which its kindly influence was warming the winds of Europe, and saving us from a glacial climate. The ground you stand on is passing through such an interval. It was under the sea once; doubtless it will be under the sea again in the future. Look into that future; look into that past. Can you measure either of those intervals in the years of common chronology? Yet all over the world the succession of geological strata proclaims the recurrence over and over again of such intervals; silent, indeed, as to positive evidence, but widening the possible limits of time’s duration to the furthest stretch of fancy.

All our great continents have been ever so many times, either in the mass or piecemeal, under the waves of the ocean. Nothing hinders that the bed of every great ocean should have been ever so many times turned into dry land. This interchange is going on now in numberless regions of sea and land. All the facts as we find them are such as they might be expected to be had this interchange been going on, as no doubt it has been, through an indefinite past. We are bound to allow millions of years for the formation of the strata that have been already examined. There may be depths below the lowest depths yet explored by geologists; there have certainly been immense intervals which have left no materials for the geologist to explore; and when all the profoundest deep of stratification shall have been explored, we may still find that the record of all these unnumbered millions of years is but, as it were, the latest page of the volume—a page that may have been preceded by a thousand others now almost irrevocably lost or become utterly illegible. There is nothing to hinder the supposition that those earlier pages, if they existed, were, amidst innumerable differences, still in their general aspect very like the latest, as long or longer, as full of the memorials of eventful circumstance, of constant change dominated by and springing from the operation of unchanging laws. As the time is absolutely incalculable which the theory of evolution requires to account for the highest forms of life upon the earth, so the time which all these considerations leave open for the work is absolutely beyond calculation. The theory cannot ask for more than the facts make it possible to offer.

We hear men sometimes dwell on an expression which they fancy to be Scriptural, ‘that there should be time no longer58;’ as if time by any possibility could ever come to an end! It is a pity that they should completely misinterpret the passage on which their opinion fancies itself to be grounded. It is a still greater pity that they should use the language of rational human beings, without being at the pains to determine whether their words have any intelligible meaning: for certainly to the human mind any beginning or end of time is wholly inconceivable. Language itself will not bear with the conception, unless it be consistent to speak of a time when time was not, of a time when time will be no more.

There is a poem, and a sweet one, by the present Poet-Laureate, in which the murmuring brook is made to speak the language of the moralist, and to proclaim the transitory nature of all human affairs, by a comparison between the short duration of man’s life and its own unceasing current—

Such is the proud language of the murmuring brook. Yet the boast is an untrue one; for if any conclusion in regard to the future can be warranted from the facts of the past, none can be more sure than that no particular brook will flow on for ever. Instead of a brook, it may become a mighty river like the St. Lawrence; it may dash over precipitous cliffs with a vaster fall and volume than Niagara; and, after all, the slow inexorable changes of the earth’s crust will one day make its flow impossible, and the channel of it shall know its stream no more. Only the flow of time is unending, of time which does nothing, but out of or without which nothing can be done,—of time, replete with glorious wonders as far back as the knowledge or the imagination of man can penetrate, through every age, through every million of years that can be rescued from forgetfulness, bearing fresh testimony, in the greatness and the endlessness of the work, to the eternal power and wisdom of the Supreme Worker.