The Story of the Earth and Man

by Sir John William Dawson

It seems not improbable that it was when the continents had attained to their greatest extension and when animal and vegetable life had again over-spread the new land to its utmost limits, that man was introduced on the eastern continent, and with him several mammalian species, not known in the Pliocene period, and some of which, as the sheep, the goat, the ox, and the dog, have ever since been his companions and humble allies. These, at least in the west of Europe, were the “Palaeolithic” men, the makers of the oldest flint implements; and armed with these, they had to assert the mastery of man over broader lands than we now possess, and over many species of great animals now extinct. In thus writing, I assume the accuracy of the inferences from the occurrence of worked stones with the bones of post-glacial animals, which must have lived during the condition of our continents above referred to. If these inferences are well founded, not only did man exist at this time, but man not even varietally distinct from modern European races. But if man really appeared in Europe in the Post-glacial era, he was destined to be exposed to one great natural vicissitude before his permanent establishment in the world. The land had reached its maximum elevation, but its foundations, “standing in the water and out of the water,” were not yet securely settled, and it had to take one more plunge-bath before attaining its modern fixity. This seems to have been a comparatively rapid subsidence and re-elevation, leaving but slender traces of its occurrence, but changing to some extent the levels of the continents, and failing to restore them fully to their former elevation, so that large areas of the lower grounds still remained under the sea. If, as the greater number of geologists now believe, man was then on the earth, it is not impossible that this constituted the deluge recorded in that remarkable “log book” of Noah preserved to us in Genesis, and of which the memory remains in the traditions of most ancient nations. This is at least the geological deluge which separates the Post-glacial period from the Modern, and the earlier from the later pre-historic period of the archæologists.[AM]

[AM] I have long thought that the narrative in Gen. vii. and viii. can be understood only on the supposition that it is a contemporary journal or log of an eye-witness incorporated by the author of Genesis in his work. The dates of the rising and fall of the water, the note of soundings over the hill-tops when the maximum was attained, and many other details, as well as the whole tone of the narrative, seem to require this supposition, which also removes all the difficulties of interpretation which have been so much felt.

Very important questions of time are involved in this idea of Post-glacial man, and much will depend, in the solution of these, on the views which we adopt as to the rate of subsidence and elevation of the land. If, with the majority of British geologists, we hold that it is to be measured by those slow movements now in progress, the time required will be long. If, with most Continental and some American geologists, we believe in paroxysmal movements of elevation and depression, it may be much reduced. We have seen in the progress of our inquiries that the movements of the continents seem to have occurred with accelerated rapidity in the more modern periods. We have also seen that these movements might depend on the slow contraction of the earth’s crust due to cooling, but that the effects of this contraction might manifest themselves only at intervals. We have further seen that the gradual retardation of the rotation of the earth furnishes a cause capable of producing elevation and subsidence of the land, and that this also might be manifested at longer or shorter intervals, according to the strength and resisting power of the crust. Under the influence of this retardation, so long as the crust of the earth did not give way, the waters would be driven toward the poles, and the northern land would be submerged; but so soon as the tension became so great as to rupture the solid shell, the equatorial regions would collapse, and the northern land would again be raised. The subsidence would be gradual, the elevation paroxysmal, and perhaps intermittent. Let us suppose that this was what occurred in the Glacial period, and that the land had attained to its maximum elevation. This might not prove to be permanent; the new balance of the crust might be liable to local or general disturbance in a minor degree, leading to subsidence and partial re-elevation, following the great Post-glacial elevation. There is, therefore, nothing unreasonable in that view which makes the subsidence and re-elevation at the close of the Post-glacial period somewhat abrupt, at least when compared with some more ancient movements.

But what is the evidence of the deposits formed at this period? Here we meet with results most diverse and contradictory, but I think there can be little doubt that on this kind of evidence the time required for the Post-glacial period has been greatly exaggerated, especially by those geologists who refuse to receive such views as to subsidence and elevation as those above stated. The calculations of long time based on the gravels of the Somme, on the cone of the Tinière, on the peat bogs of France and Denmark, on certain cavern deposits, have all been shown to be more or less at fault; and possibly none of these reach further back than the six or seven thousand years which, according to Dr. Andrews, have elapsed since the close of the boulder-clay deposits in America.[AN] I am aware that such a statement will be regarded with surprise by many in England, where even the popular literature has been penetrated with the idea of a duration of the human period immensely long in comparison with what used to be the popular belief; but I feel convinced that the scientific pendulum must swing backward in this direction nearer to its old position. Let us look at a few of the facts. Much use has been made of the “cone” or delta of the Tinière on the eastern side of the Lake of Geneva, as an illustration of the duration of the Modern period. This little stream has deposited at its mouth a mass of débris carried down from the hills. This being cut through by a railway, is found to contain Roman remains to a depth of four feet, bronze implements to a depth of ten feet, stone implements at a depth of nineteen feet. The deposit ceased about three hundred years ago, and calculating 1300 to 1500 years for the Roman period, we should have 7000 to 10,000 years as the age of the cone. But before the formation of the present cone, another had been formed twelve times as large. Thus for the two cones together, a duration of more than 90,000 years is claimed. It appears, however, that this calculation has been made irrespective of two essential elements in the question. No allowance has been made for the fact that the inner layers of a cone are e necessarily smaller than the outer; nor for the further fact that the older cone belongs to a distinct time (the pluvial age already referred to), when the rainfall was much larger, and the transporting power of the torrent great in proportion. Making allowance for these conditions, the age of the newer cone, that holding human remains, falls between 4000 and 5000 years. The peat bed of Abbeville, in the north of France, has grown at the rate of one and a half to two inches in a century. Being twenty-six feet in thickness, the time occupied in its growth must have amounted to 20,000 years; and yet it is probably newer than some of the gravels on the same river containing flint implements. But the composition of the Abbeville peat shows that it’s a forest peat, and the erect stems preserved in it prove that in the first instance it must have grown at the rate of about three feet in a century, and after the destruction of the forest its rate of increase down to the present time diminished rapidly almost to nothing. Its age is thus reduced to perhaps less than 4000 years. In 1865 I had an opportunity to examine the now celebrated gravels of St. Acheul, on the Somme, by some supposed to go back to a very ancient period. With the papers of Prestwich and other able observers in my hand, I could conclude merely that the undisturbed gravels were older than the Roman period, but how much older only detailed topographical surveys could prove; and that taking into account the probabilities of a different level of the land, a wooded condition of the country, a greater rainfall, and a glacial filling of the Somme valley with clay and stones subsequently cut out by running water the gravels could scarcely be older than the Abbeville peat. To have published such views in England would have been simply to have delivered myself into the hands of the Philistines. I therefore contented myself with recording my opinion in Canada. Tylor[AO] and Andrews[AP] have, however, I think, subsequently shown that my impressions were correct. In like manner, I fail to perceive, and I think all American geologists acquainted with the pre-historic monuments of the western continent must agree with me, any evidence of great antiquity in the caves of Belgium and England, the kitchen-middens of Denmark, the rock-shelters of France, the lake habitations of Switzerland. At the same time, I would disclaim all attempt to resolve their dates into precise terms of years. I may merely add, that the elaborate and careful observations of Dr. Andrews on the raised beaches of Lake Michigan, observations of a much more precise character than any which, in so far as I know, have been made of such deposits in Europe, enable him to calculate the time which has elapsed since North America rose out of the waters of the Glacial period as between 5500 and 7500 years. This fixes at least the possible duration of the human period in North America, though I believe there are other lines of evidence which, would reduce the residence of man in America to a much shorter time. Longer periods have, it is true, been deduced from the delta of the Mississippi and the gorge of Niagara; but the deposits of the former have been found by Hilgard to be in great part marine, and the excavation of the latter began at a period probably long Anterior to the advent of man.

[AN] “Transactions, Chicago Academy,” 1871.

[AO] “Journal of Geological Society,” vol. xxv.

[AP] “Silliman’s Journal,” 1868.

But another question remains. From the similarities existing in the animals and plants of regions in the southern hemisphere now widely separated by the ocean, it has been inferred that Post-pliocene land of great extent existed there; and that on this land men may have lived before the continents of the northern hemisphere were ready for them. It has even been supposed that, inasmuch as the flora and fauna of Australia have an aspect like that of the Eocene Tertiary, and very low forms of man exist in that part of the world, these low races are the oldest of all, and may date from Tertiary times. Positive evidence of this, however, there is none. These races have no monuments; nor, so far as known, have they left their remains in Post-pliocene deposits. It depends on the assumptions that the ruder races of men are the oldest; and that man has no greater migratory powers than other animals. The first is probably false, as being contrary to history; and also to the testimony of palaeontology with reference to the laws of creation. The second is certainly false; for we know that man has managed to associate himself with every existing fauna and flora, even in modern times; and that the most modern races have pitched their tents amid tree-ferns and Proteaceæ, and have hunted kangaroos and emus. Further, when we consider that the productions of the southern hemisphere are not only more antique than those of the northern, but, on the whole, less suited for the comfortable subsistence of man and the animals most useful to him; and that the Post-pliocene animals of the southern hemisphere were of similar types with their modern successors, we are the less inclined to believe that these regions would be selected as the cradle of the human race.