The duration of each of the phases of Croll's theory corresponds also, on the whole, remarkably well with that required for each phase of the geological record. They would average about 40,000 years each for Croll's phases, and a less time can hardly be allowed for the immense amount of geological work in the way of denudation and deposition, elevation and depression, and changes of fauna and flora which have occurred since the commencement of the great refrigeration in the late Pliocene. In fact the only reasonable doubt seems to be whether Croll's times are sufficient, and whether, as Lyell was inclined to think, the first and greatest glaciation must not be carried back to the extreme period of high eccentricity which occurred about 700,000 years ago.
Unless we are prepared to ignore all these considerations and deny that Croll's theory, as amended by Sir R. Ball, has had any appreciable effect on the conditions of the glacial period, it follows with mathematical certainty, that this period, taking it from the commencement of the great refrigeration in the Pliocene to its final disappearance in the Recent, must have lasted for about 200,000 years. And as man clearly existed in the pre-glacial period, and was already widely spread and in considerable numbers in the early glacial, 250,000 years may be taken as an approximation to the minimum duration of the existence of the human race on the earth. To this must be added an indefinitely long period beyond, unless we are prepared to disprove the apparently excessively strong evidence for its existence in the Pliocene and even in the Miocene periods; evidence which has been rapidly accumulating of late years; and to which, as far as I know, there has been no serious and unbiassed attempt at scientific refutation; and to which confirmation is given by the undoubted fact that the Dryopithecus, the Hylobates, and other quadrumana, closely resembling man in physical structure, already existed in the Miocene, and, if Professor Ameghino's discoveries referred to at p. [264] are confirmed, in the vastly more remote period of the early Eocene.
[CHAPTER X.
QUATERNARY MAN.]
No longer doubted—Men not only existed, but in numbers and widely spread—Palæolithic Implements of similar Type found everywhere—Progress shown—Tests of Antiquity—Position of Strata—Fauna—Oldest Types—Mixed Northern and Southern Species—Reindeer Period—Correspondence of Human Remains with these Three Periods—Advance of Civilization—Clothing and Barbed Arrows—Drawing and Sculpture—Passage into Neolithic and Recent Periods—Corresponding Progress of Physical Man—Distinct Races—How tested—Tests applied to Historical, Neolithic, and Palæolithic Man—Long Heads and Broad Heads—Aryan Controversy—Primitive European Types—Canon Taylor—Huxley—Preservation of Human Remains depends mainly on Burials—About forty Skulls and Skeletons known from Quaternary Times—Summary of Results—Quatrefages and Hamy—Races of Canstadt—Cro-Magnon—Furfooz—Truchere—Skeletons of Neanderthal and Spy—Canstadt Type oldest—Cro-Magnon Type next—Skeleton of Cro-Magnon—Broad-headed and Short Race resembling Lapps—American Type—No Evidence from Asia, Africa, India, Polynesia, and Australia—Negroes, Negrillos, and Negritos—Summary of Results.
The time is past when it is necessary to go into any lengthened argument to prove that man has existed throughout the Quaternary period. Less than half a century has elapsed since the confirmation of Boucher-de-Perthes' discovery of palæolithic implements in the old gravels of the Somme, and yet the proofs have multiplied to such an extent that they are now reckoned, not by scores or hundreds, but by tens of thousands. They have been found not in one locality or in one formation only, but in all the deposits of the Quaternary age, from the earliest to the latest, and in association with all the phases of the Quaternary period, from the extinct mammoth, woolly rhinoceros, and cave-bear, to the reindeer, horse, ox, and other existing animals. No geologist or palæontologist, who approaches the subject with anything like competent knowledge, and without theological or other prepossessions, doubts that man is as much a characteristic member of the Quaternary fauna as any of these extinct or existing animals, and that reasonable doubt only begins when we pass from the Quaternary into the Tertiary ages. I will content myself, therefore, instead of going over old ground and proving facts which are no longer disputed, with showing what bearing they have on the question of human origins.
Palæolithic Celt (type of St. Acheul).
From Quaternary deposits of the Nerbudda, India.