The Chain of Life in Geological Time / A Sketch of the Origin and Succession of Animals and Plants

by Sir John William Dawson

(1) The occurrence of human remains with those of animals now extinct affords no certain evidence of antiquity. Admitting that human remains are found along with those of the mammoth in Europe, and with those of the mastodon in America, the question remains, How late did these species survive? In Europe we know that several large animals now extinct existed up to comparatively modern times. This is the case with the Irish deer (Megaceros), the urus, the aurochs, and the reindeer, in temperate Europe. How long previously the mammoth or the hairy rhinoceros disappeared we do not know, but need not suppose the time very long.

(2) The accumulation of sediment or of stalagmite over human remains in caverns is not necessarily indicative of very great antiquity. We know that in favourable circumstances mud, sand, and gravel may be rapidly deposited in caves by land floods or river inundations, and that débris of various sorts accumulates in such places from decay of rock and vegetable and animal agencies. The deposition of stalagmite is also very variable in its rate; and the fact that it is being very slowly deposited in any cave now does not prove that more rapid deposition may not have taken place formerly. Dawkins and others have ascertained a rate of a quarter of an inch per annum in some caverns; and this would allow the stalagmite crust of Kent’s cave, for which an antiquity of half a million of years has been claimed, to have been formed in a thousand years.

Fig. 192.—Sketch of a Mammoth, carved on a portion of a Tusk of the same Animal (Lartet).

(3) The erosion of river valleys to great depths since the Glacial period fails to establish the great antiquity of the caves left on their sides or the high level gravels of their banks. Throughout the northern hemisphere, the river valleys are of old date, and were merely filled with loose detritus in the Glacial age. The sweeping out of this débris would be a rapid process, more especially when changes of level were occurring, and when the rainfall was greater than at present. Besides, as Croll has well remarked, the actual configuration of our continents, the amount of drift still remaining, and the imperfect manner in which the river valleys have been cleared out, all testify to the comparative recency of the Glacial period.[91] These considerations would, indeed, materially reduce the antiquity which he claims on astronomical grounds for the ice age.

(4) The growth of peat and the deposition of silt are very deceptive as indications of great antiquity. For instance, accurate observations made by a French engineer in the construction of docks at St. Nazaire,[92] show that in 1,600 years the Loire had deposited over Gallo-Roman remains six metres of mud. Relics of the Bronze age occur below these at a depth indicating 500 years previously as their date; and the beginning of the modern deposit of the Loire would, on the same evidence, be only 6,000 years ago. Hilgard’s observations on the delta of the Mississippi in like manner tend greatly to reduce our estimates of the time occupied in the deposit of the modern silt of that river. The peat deposit at Abbeville, at the mouth of the Somme, has been supposed to have required 30,000 years for its formation. But this estimate was based upon the present rate of growth; and, as Andrews has shown, the fact admitted by Boucher de Perthes, that birch stems three feet high stand in this peat, implies a much more rapid rate, which is also proved by the depth at which Roman remains have been found. In like manner the Scandinavian peats, to which a fabulous antiquity has been ascribed, have been proved to be comparatively modern by the depths at which metallic works of art are found in them.

(5) The paucity of remains of Palæocosmic men in Europe, with their wide distribution, indicate that their sojourn was not long, or that the population was very small and much scattered. Even in a few thousands of years, an active and vigorous people, living in a country well supplied with food, must have multiplied greatly, and must have left considerable remains. On the theory that these men inhabited Europe even for 2,000 years, we have to suppose that the greater part of their remains have been swept away, or remain under the waters, or buried out of sight in diluvial sediments.

(6) Much importance has been attached to the early works and high culture of Egypt and Chaldæa, as evidence of vast time during which arts were growing from a supposed rude stone age. But it must be observed that no such period is known to antedate civilisation in the East, and that if the early empires were established by survivors of the Deluge, they must have brought with them the culture of Antediluvian times. Farther, the notion of men emerging from a half-brutal state, and from the use of the rudest implements, is purely conjectural and not supported by facts. In America, where the semi-civilised agricultural races are unquestionably the oldest, the rudest possible implements were used by these partially civilised agricultural people along with polished stone and metal; and Schliemann has shown that a rude stone age succeeded the civilisation of Troy, and this at a time when Phœnicia and Egypt were at the height of their civilisation. Such facts, which might fill volumes, show how little value is to be attached to supposed ages of rough and polished stone.

(7) The difficulties attending the establishment of geological dates for deposits like those containing the remains of men are very great. They are altogether superficial and local, not widespread marine beds in which a distinct order of superposition can be clearly traced. They are not easily separated from the glacial beds below, or from those above which have been modified by human agency, by land-floods, or by landslips. Thus the application of geological criteria of age to them is very difficult and uncertain. Evidence of this could easily be given, in the many errors which have been promulgated, and which have had to be retracted by their authors, or have been disproved by the observations of others. For example, no country was at one time richer in supposed evidences of the antiquity of man than Scandinavia; but Professor Torell, the director of the Geological Survey of Sweden, has recently made a careful re-examination of the facts, and has found that there is no evidence whatever of the existence of man in Scandinavia before the Neolithic or polished stone age. There are, however, evidences of considerable changes of level since that time, and it would seem even since the twelfth century of our era. The remarkable and seemingly inexcusable errors of observation referred to in Professor Torell’s memoir, should enforce a caution on geologists as to the uncertainties of such evidence. Lyell sifted the testimony bearing on this subject with great care in the first edition of his Antiquity of Man. In later editions he had to make large abatements, and now much of the evidence in the latest edition would have to be withdrawn or otherwise applied.