The epoch following on after the Eocene is designated as the Miocene.
We must remember that, though recent in a geological sense, yet it is immensely remote when measured by the standard of years. We must inquire into all the surroundings of this far away time. The geographical features must have been widely different from the present.
In the first place, the elevation of land to the north must have been sufficient to have connected the land areas of the Northern Hemisphere--North America, with Asia<27> and Greenland; and this latter country must have been united with Iceland, and, through the British Islands, with Europe. But, to compensate for this land ma.s.s to the north, large portions of Central and Southern Europe were beneath the waves.<28> The proof of this extended ma.s.s of land is to be found in the wide distribution of similar animals and plants in the Miocene time.
All the chief botanists are agreed that the north Polar region was the center from which plants peculiar to the Eocene and Miocene epochs spread into both Europe and America.<29> We may mention that the famous big trees of California are simply remnants of a wide-spread growth of these trees in Miocene times. They can be found in a fossil state at various places in British America, in Greenland, and in Europe. They are supposed to have originated somewhere in the north, and spread by these land connections we have mentioned into both Europe and America. But this is not the only tree that grew in the Miocene forests of both continents. The magnolia, tulip-tree, and swamp cypress are other instances.<30> Eleven species, growing in the Rocky Mountain regions in Rocene times, found their way to Europe in the Miocene times,<31> driving before them the plants of a tropical growth that had hitherto flourished in England. Now this implies land connection between the two continents. Furthermore, animals both large and small are found common to the two countries.<32> The climate over what is now the North Temperate Zone, and even further. north, must have been delightful.
There is ample testimony to this effect in the rich vegetative remains over wide areas.
In Spitzbergen, within twelve degrees of the pole, where now a dwarf willow and a few herbaceous plants form the only vegetation, and the ground is most of the time covered with snow and ice, there were growing, in Miocene times, no less than ninety-five species of trees, including yews, hazels, elders, beech, elms, and others.<33> But it is in the Miocene forests of the continent of Europe where we meet with evidence of a singularly mild climate.
There were at least eleven species of palms growing in Switzerland; and one variety of them grew as far north as Northern Germany.<34>
We can not give a list of all the species. On the one hand, there were elms, willows, poplars, oaks, and beeches, thus far similar to the forest growth of temperate regions. Mingled with these were forests of trees like the tulip-tree, swamp cypress, and liquid amber or sweet gum of the southern part of the United States--plants whose home is in the warm and moist regions of the earth. But there were also representatives of the tropical regions--such as fig-trees, cinnamon-trees, and camphor-trees: these are found growing now in tropical countries.
Fruit-trees of the cherry, plum, and almond species were also to be seen. Prof. Heer points out how all this should convince us that a large part of Europe, in the Miocene Age, possessed a climate not unlike that of the Madeira or Canary Islands to-day. He calls especial attention to the fact that these trees were nearly all of evergreen species, and that a severe winter would destroy them. He finds one hundred and thirty-one species of the Temperate Zone--species that can stand a moderate amount of cold, but not very hot and dry climates. He finds eighty-five species of tropical plants that could not possibly live where the Winters are severe. Mingled with these were nearly three hundred species whose natural home is in the warm, temperate portions of the earth. The only way you can explain this motley a.s.semblage of trees is, to suppose that in what is now Europe was a climate free from extremes, allowing the trees to put forth flowers and fruits all the year round. "Reminding us," says Prof. Heer, "of those fortunate zones where Nature never goes to rest."<35>
Ill.u.s.tration of Miocene Mammals.-----------
Let us now inquire as to the animals that roamed through these great forests we have been describing. The Miocene period extended over a long lapse of time, and considerable change took place among the animals belonging to the different parts of this age. We will only give a general outline for the whole period. The marsupials lingered along into the early stages of this period, and then disappeared from Europe. The rhinoceros were present in the early stages, and continued through the entire age. We meet in this period animals of the elephant kind, two species, the mastodon and deinotherium. Antelopes and gazelles wandered in vast troops over the plains of Hungary, Spain, and Southern France.
Carnivorous animals resembling tigers and hyenas found abundance of animal food. Herds of horse-like animals fed on the rich herbage of the meadows. The birds were largely represented. In the woods were to be seen flocks of gayly feathered paroquets and trogons. On the plains secretary-birds hunted the serpents and reptiles, which furnished them food--and eagles were on the watch for their prey. Cranes waded in the rivers for fish. Geese, herons, and pheasants must have been abundant.
Our main interest centers in the order Quadrumana. We must remember that this order appeared in the Eocene. Several species were present in the Miocene. They wandered in the forests of France, Switzerland, Germany, and Italy, and doubtless found abundant food in the figs and bread-fruit, walnuts, almonds, dates, and other nuts growing there.<36> One of the most important is regarded as belonging to the same genus as the Gibbons.<37> This is the genus which has been sometimes regarded as making a nearer approach to man than any other monkey.<38> Others, however, consider it as belonging to an extinct family.<39> In addition to this species there were at least three other species: thus there was no absence of simian life in the Miocene.<40>
From the sketch we have thus far drawn of the Miocene Age, it seems to have been a very favorable one in every respect. One writer<41> affirms, that "the world never experienced a more beautiful period." And indeed it seems as if the facts bear out this statement. A genial, temperate climate was the rule, even to high northern lat.i.tudes. We need not doubt but that there were gra.s.sy plains, wooded slopes, and rolling rivers.
Was man present to take advantage of all these favorable surroundings?
Did he wander through the evergreen forests, and hunt the deer, antelope, and hogs--the hipparions, and mastodons, and deinotheres--then so numerous?<42> We know of no inherent improbability of his existence at that time. An ape belonging to a highly organized genus was then living in Europe. Every condition considered necessary for the primeval Garden of Eden was then satisfied. Let us stop for a minute and examine the nature of the evidence considered sufficient to prove the presence of man during any of the past geological ages.
Should we be so fortunate as to find portions of the bones of the human skeleton in a geological formation in such positions that they could not possibly have been introduced there since the deposition of the containing bed, it would of course prove that man was at least as old as the formation itself. But it happens that human remains in beds of a previous geological age are very rare. Indeed, human remains in formations of the Pleistocene Age,<43> during which we have ample testimony, as we shall see, of the presence of man, are very rare. The cases in which there can be no doubt can be reckoned on the fingers. The explanation of this state of things is not at all difficult, for it is only under very rare circ.u.mstances that portions of the bones of animals even larger than man are preserved to us in geological strata. Vast numbers die and vanish away without leaving a trace behind them for every fragmentary bone we recover. In the case of man we must remember that, in previous eras, he was present in very small numbers; that, owing to his intelligence, he would not be as liable to be drowned and swept away, and so mingle his remains with beds of river detritus then forming, as were animals. Mr. Lyell has made some remarks on the draining of the Haarlem Lake by the government of Holland in 1853, which shows that even favorable circ.u.mstances do not always preserve remains for future inspection. Though called a lake, this body of water was an arm of the sea, covering about forty-five thousand acres. The population which had lived on the sh.o.r.es of the lake was between thirty and forty thousand souls. "There had been many a shipwreck, and many a naval fight on those waters, and hundreds of Dutch and Spanish soldiers and sailors had met there with a watery grave," yet not a solitary portion of the human skeleton was to be found in its bed.<44> Thus we see that, in the majority of cases, we must rely on other evidence than the presence of human bones to prove the existence of man in the geological periods of the past. In the case of the Haarlem Lake again, there was found the wreck of one or two vessels, and some ancient armor. So, had it been a disputed point whether man was a denizen of this planet at the time when the area in question was covered by water, it would have been settled beyond a doubt by these relics of his industry, even though portions of the human frame itself were entirely wanting. And, in reality, proofs of this nature are just as satisfactory as it would be to discover human bones. If, on a desert island, we find arrow-heads, javelins, a place where there had been a fire, split bones, and other _debris_ of a feast, we are as much justified in a.s.serting that man had been there, as we would be had we seen him with our own eyes. In the same manner, if we detect in any strata of the past any undoubted products of human industry--such as weapons, or implements and ornaments--in such position that we know they could not have been deposited there since the formation of the bed itself, we have no hesitancy in a.s.serting that man himself is of the same antiquity as the strata containing the implements. In the great majority of cases, this is the only kind of evidence possible to advance.
It is now well known that the first stage in the culture of any people, is what is called the Stone Age. That is to say, their weapons and implements were made from stone, or at least the majority of them were.
We will discuss on another page this point, and also the grounds leading us to infer that many of the extremely rude forms are really the work of man.
Let us now return to the Miocene Age, in which we are to seek for the presence of man. In 1867 a French geologist, by the name of Bourgeois, who had been searching some beds of the Miocene Age, near Thenay, France, found a number of flints of such a peculiar shape, that he concluded they could only be explained by supposing that man formed them. In this case there is to question as to the age of the stratum containing the flints. All geologists are agreed that it is of the Miocene Age. The question then is, whether the flints were artificially cut or not. On this question there has been a great division of opinion, and we can not do better than to examine and see where the Princ.i.p.al scientific men stand on this point.
In 1872, at the scientific congress in Brussels, this question was referred to a committee composed of the most competent men from the different countries of Europe. We are sorry to say that, after a thorough consideration of them, the judges were unable to agree. Some accepted them, others rejected them, and still others were undecided. Some of the latter have since become convinced by recent discoveries.<45>
Since this discovery, similar specimens have been described as having been found in Portugal, and from another locality in France. Some men of the highest authority accept these flints as proving the presence of man in Miocene times. This is supported by such men as Quatref.a.ges, Hamy, Mortillet, and Capellini.<46> These are all known to be competent and careful geologists. Another cla.s.s does not think the evidence strong enough to declare these flints of human origin, and so do not think it proved that man lived in Europe in Miocene times; but do believe that we will eventually find proofs of his existence during that era in the warm and tropical regions of the globe. This is the view of such men as Lubbock, Evans, Huxley, and Winch.e.l.l. Still others say that, during the vast lapse of years since Miocene times, all the species of land mammals then alive have perished<47>--their place being taken by other species--and therefore it is incredible that man, the most highly specialized of all animals, should have survived. And hence, if these Thenay flints are really artificial in their origin, it is more reasonable to suppose they were cut by one of the higher apes, then living in France, than by man. This is the view of Prof. Dawkins and Prof. Gaudry.<48> As to the last view, it is surely but reasonable to suppose, with Quatref.a.ges,<49> that the superior intelligence of man would serve to protect him from the operation of causes that would effect the extinction of lower animals. Hence, unless some evidence be produced to show that species of apes are known to make rude stone implements, or some evidence that they did this in past ages, we must believe, with Geikie and others, that these flints prove that Miocene man lived in France, unless indeed we refuse to believe that they are artificial.
It also seems to us that those who hold to the view that man was living in other parts of the world, as Asia, during the Miocene Age, ought readily to admit that a few wandering bands might penetrate into Europe.<50> The climate was tropical, there was an abundance of animal life, and, if man was living anywhere, it is very reasonable to suppose that, at some epoch during the course of the Miocene Age, he would have found his way to Europe, unless shut off by the sea. It therefore seems to us that the presence of those cut flints is conclusive of the presence of man in Europe during the Miocene Age. At the same time we can not affirm that this is the conclusion of the scientific world. They seem to have heeded the remark of Quatref.a.ges, that "in such a matter there is no great urgency," and are waiting for further discoveries.
Thus far in our review we have noticed the steady progress in the forms of life. In the Miocene Age we have seen all the types of life below man present, and some indications of the presence of man himself. We must now learn what we can of the Pliocene Age, the last division of the Tertiary Age.
The Pliocene Age need not detain us long. Considerable changes in the geography of both Europe and America were going forward during the Miocene Age, and the result was quite a change in climate. There was a steady elevation of the Pacific coast region of America, and, as a consequences a period of great volcanic outbursts in California and Oregon.<51> At the same time the bridge connecting Asia and America was severed.<52> In Europe the Mediterranean area was elevated; but the land connecting Greenland with Europe sank, allowing the cold waters of the Arctic to communicate with both the North Sea and the Atlantic--England at that time forming part of the great peninsula extending north and west from Europe.<53> The climate during the Pliocene Age was cooler than that of the Miocene. This is marked in the vegetation of that period. The palms and the cinnamon trees, which in Miocene times grew in Germany, flourished no farther north than Italy during the Pliocene.<54>
Count DeSaporta, who made special researches in the flora of this period, found the remains of a forest growth buried under lava on the side of a mountain in Cantal France, at an elevation of about four thousand feet above the level of the sea. This consisted princ.i.p.ally of pines. This shows that probably all Northern Europe was covered with somber forests of pine. In the same section he found, buried under volcanic ash, a vegetation consisting mostly of deciduous trees--maples, alders, poplars, willows, elms, and ashes. As this was growing at the height Of about twenty-three hundred feet in Cantal France, it probably represents the vegetation of Britain and Northern Germany. Finally, the vegetation of Central and Southern France, as well as Northern Italy, was intermediate in character between the luxuriant evergreen forests of the Miocene Age and that now growing there. The tropical character of the vegetation was evidently pa.s.sing away. The climate over a large part of Europe was now temperate, though probably warmer than at present.<55>
In the Mammalia we have to notice the disappearance of some species, and the arrival and spread of some others. The apes living as far north as Germany in the Miocene Age were restricted to Southern France and Italy in the Pliocene, and, at its close, vanished altogether from Europe.
The first living species of mammals is found in the remains of the hippopotamus that frequented the rivers of Pliocene times. The mastodon of Miocene times was still to be seen, but along with it was a species of true elephants. The hipparion survived into this epoch, but the horse also makes its appearance. Great quant.i.ties of deer roamed over the land; and, as might be expected where they were so abundant, the carnivorous animals allied to the bears and wolves, panthers, linxes, and tigers, were also to be found. "At night," says Mr. Dawkins, "the Pliocene forests of Central France echoed with the weird laughter of the hyena."
The gradual lowering of the climate is also shown by the remains of the mollusks deposited in beds of marine or sea formation during different eras of this age. It is found that the earlier the bed, the more southern mollusks are found in it. This shows us that, all through the Pliocene Age, the waters of the seas surrounding England were gradually growing cooler, thus compelling the retreat of those mollusks fitted only for a warm climate, and allowing a gradual increase in those species fitted for cold or northern lat.i.tudes. We also find, in deposits made near the close of Pliocene times, numbers of stone which show all evidence of having been borne thither by means of ice. So we may conclude that rafts of ice came floating down the North Sea during the closing period of the Pliocene Age.<56> Still, during the entire length of the Pliocene Age, Europe certainly offered an inviting home for man.
Not only were the higher orders of animals present, but at least one living species was known. We find more proofs of his presence, but whether they are sufficient to convince us that man really lived during that epoch is to be seen.
Prof. Whitney has brought to the attention of the scientific world what he considers ample evidence of the presence of Pliocene man in California. We reserve this for discussion in another place. We will only remark, at present, that the evidence in this case is regarded as sufficient by some of the best of American Scholars.<57> We simply mention them here, so that they may be borne in mind when we see what evidence Europe has to offer on this point. In 1863, M. Desnoyers, of France, discovered, in a stratum which he considered Pliocene, some bones of elephants and other animals cut and scratched in such a manner that he considered the cuts to be the work of man. As showing how cautious geologists are of accepting such conclusions, we mention this case. There was found in the same bed the remains of an extinct beaver.
The question was at once raised, whether rodents by gnawing these bones could not have produced the cuts in question. Sir Charles Lyell, by actual experiments in the Zoological Gardens in London, soon showed that this was probably the fact.<58> Yet Sir John Lubbock thinks it quite likely some of them were of human origin.<59> Subsequently, however, M. Bourgeois discovered in the same bed worked flints, about the human origin of which there seems to be no doubt;<60> but a more careful study of the formation in which they occur has raised questions as to its age.
Though usually held to be Pliocene, some careful observers consider it to be of a later age. Geologists can not be accused of rashly accepting statements as to the antiquity of man.
In 1867 there was discovered, in Northern Italy, a human skull in a railway cutting at a depth of nearly fifty feet. This stratum contains remains of several Pliocene animals. This is held to prove the existence of Pliocene man by several eminent observers, amongst others Prof.
Cocchi, of Italy, and Forsyth Major.<61> But in this case Mr. Dawkins contends that it was not found under such conditions as render it certain that the stratum had been undisturbed, and so does not prove to a certainty that it was of the same age as the stratum.<62> And Mr. Geikie thinks that the stratum itself is of a later age than the Pliocene.<63> It is but right that geologists should thus carefully scan all the evidence produced.
Ill.u.s.tration of Cut on Bones of a Whale from Pliocene Deposit.--------------------------------
In 1876 Prof. Capellini discovered, in a Pliocene deposit in Italy, the bones of a whale, which were so marked with cuts and incisions that he thought the only explanation was to say they had been cut by men. In this case<64> there is no dispute as to the age of the stratum. Neither is there much doubt but that the cuts are the work of man. It is quite true that Mr. Evans has suggested that they may be the work of fishes.
In this he is followed by Prof. Winch.e.l.l.<65> But there appears to be little ground for such belief, because the cuts are all on the outside faces of rib-bones, and the outer faces of the backbones. From the position occupied by the remaining portions of the skeleton, Prof.
Capellini is sure that the animal had run aground, and, in that condition, was discovered and killed by men, who then, by means of flint knives, cut away such portions of food as they wished. It must have been lying on its left side, since the cuts were all made on bones of the right.<66> It is not probable that fishes would have been apt to choose the outside faces of the ribs on the right side for their meals. These cut bones have been carefully examined by many competent men, who have agreed with Capellini that they are the work of men.<67> Mr. Dawkins thinks the cuts were artificial, but he says, "It is not, however, to my mind satisfactorily shown that these were obtained from undisturbed strata."<68> Now these bones have been found in several localities, always in Pliocene deposits, which formed the sh.o.r.es of the Pliocene sea.<69> Knowing how carefully geologists inquire into all the surroundings of a find, surely, if Capellini and others are the competent men they are admitted to be, they would have informed us long ago if they were not found in undisturbed strata.
Mr. Dawkins also objects because fragments of pottery were found in the strata. "Pottery," says he, "was unknown in the Pleistocene Age,<70> and therefore is unlikely to have been found in the Pliocene."<71> Mr.
Geikie says this objection is founded on a mistake, as Prof. Capellini told him the pottery was found lying on the surface, and was never for a moment imagined by him as belonging to the same age as the cut bones.<72> There is also the objection, that, inasmuch as all the mammals then alive except one have perished, it is more than likely that, had man been in existence then, he too would have disappeared.
We considered this point fully when speculating as to the presence of man in the Miocene: so we have nothing further to offer. We might, however, suggest that, if the hippopotamus amongst mammals could survive all the changing time since the Pliocene, as it has done, it seems no more than fair to admit equal power of endurance to the human species.
The position then of the scientific world as to the Pliocene Age of man is, on the whole, more decided in its favor than for the Miocene Age.
Quite a number of eminent scholars, whose conclusions are worthy of all respect, unhesitatingly affirm the existence of Pliocene man in Europe.
Others are not quite ready to admit his existence in Europe, but do think he was in existence elsewhere. Still others, with all due respect for the discoveries of Capellini, think it more prudent to await further discoveries. The reader, who has followed us through this brief outline of the past, can join which of the cla.s.ses he will, and be sure of finding himself in good company.
This completes our review of past geological ages. With the termination of the Pliocene Age we find ourselves on firmer ground. We only wish to call attention once more to the gradual unfolding of life. We see that the rule has been that everywhere the lower forms of life precede the higher. In the plant world flowerless plants precede the flowering ones.
The coal we burn to-day is mainly the remains of the wonderful growth of the flowerless vegetation of the Paleozoic Ace. When flowering plants appear, it is the lower forms of them at first.
It was long ages before trees with deciduous leaves appeared. The growth of animal life is equally instructive. First invertebrate life, then the lowest forms of vertebrate life. The fishes are followed by amphibians--then reptiles, then birds. The first mammal to appear was the lowest organized of all--the marsupials. And we have seen the sudden increase of mammalian life in Tertiary times. We notice, in all the divisions of life, a beginning, a culmination, and a decline. There has never been such a growth of flowerless plants as in the Paleozoic, and flowering plants probably culminated in the Miocene. The same rule holds good for the animal world also. As man is the most highly organized of all the animals, we can not hope to find any evidence of his presence until we find proofs of the presence of all the lower types of life. Of course future discoveries may change our knowledge when the series is complete; but, from our present stand-point, he could not have lived before the Miocene Age, and we have seen how faint and indecisive are the proofs of his presence even then. But should it finally be proved, beyond all dispute, that man did live in the Miocene Age, we must observe that this is but a small portion, but a minute fraction, of the great lapse of time since life appeared on the globe. We are a creation of but yesterday, even granting all that the most enthusiastic believer in the antiquity of man can claim.
Ill.u.s.tration of The Mastodon.-------------
REFERENCES
(1) The ma.n.u.script of this chapter was submitted to Prof.
Winch.e.l.l, of the University of Michigan, for criticism.
(2) Dana"s "Manual of Geology," p. 146.
(3) Ibid. p. 147.
(4) Nicholson"s "Manual of Zoology," p. 59.
(5) Dana"s "Manual of Geology," p. 74.
(6) Nicholson"s "Manual of Zoology," p. 42.
(7) Dana"s "Manual of Geology," p. 323.
(8) Nicholson"s "Zoology," p. 402.
(9) Dana"s "Geology," p. 302.
(10) Dawkins"s "Early Man in Britain," p. 6.
(11) Dana"s "Geology," p. 382.
(12) Haywood"s, Heer"s, "Primeval World of Switzerland."
(13) Dana"s "Man. Geology," p.395.
(14) Nicholson"s "Man. Zoology," p.42.
(15) Marsh: "American a.s.soc. Rep.," 1877.
(16) Marsh: "American a.s.soc. Rep.," 1877.
(17) Dawkins"s "Early Man in Britain," p. 6.