In the preceding Chapter, the remains of Palaeolithic Man were studied in relation to the associated animals (especially mammals), and again (so far as possible) in connection with the accompanying implements. In the comparison of the different types of implement, evidence was adduced to shew that certain forms of these are distinctive of corresponding geological horizons. Of the three series, (1) human remains, (2) mammalian remains, (3) stone implements, the first two, (1) and (2), have been compared as well as (1) and (3). A comparison between (2) and (3) has now to be instituted. And this is of interest, for mammalian remains have been found in the presence of implements where no human bones could be discovered. Moreover the expectation is well founded, whereby the mammalian fauna will prove to supply information unobtainable from either human skeletons or implements by themselves. That information will bear upon the climatic conditions of the different phases which mark the geological history of Man. And in this way, a more perfect correlation of the past history of Man with the later geological history of the earth may be fairly anticipated.

In Chapter IV, use was frequently made of the expression ‘southern,’ ‘temperate’ or ‘sub-arctic,’ in connection with the various groups of mammals mentioned in Table A. And while the geological period is limited, during which these investigations are profitably applicable, yet the matter is one of no small importance. For the very fact that the fauna can be described in one case as ‘southern’ in character, in another as ‘temperate,’ suggests some variation of climate. And the relation of the history of Man to the great variation of climate implied in the expression ‘Glacial Period,’ may be reasonably expected to receive some elucidation from this branch of study. It will be noticed that Man himself is at present comparatively independent of climate, and even in earlier times he was probably less affected than some other animals. But while the importance of these studies must be recognised, it is also very necessary to notice that as elsewhere so here the difficulties are great, and pitfalls numerous.

It is no part of the present work to attempt a history of the stages through which opinion passed in developing the conception embodied in the phrase ‘Ice-Age.’ Long before that idea had been formulated, the presence of animal remains both in cave and alluvial deposits was a matter of common knowledge. The late Professor Phillips is believed to have been the first to make definite use of the terms ‘pre-glacial’ and ‘post-glacial’ in reference to the later geological formations (1855). And to the pre-glacial era that geologist referred most of the ossiferous caves and fissures.

But in 1860, this, the accepted view, was overthrown by the late Dr Falconer[40] at least so far as the caves (with the exception of the Victoria Cave) then explored in Britain were concerned. In the same year, the post-glacial position and antiquity of various brick-earths and gravels of the Thames valley were considered to have been definitely established by the late Professor Prestwich. It is very important to note in this connection, that the palaeontological evidence of those brick-earths was nevertheless held to indicate pre-glacial antiquity and thus to contradict the evidence of stratigraphy. The method employed in the latter mode of enquiry consisted in ascertaining the relation of the boulder-clay to certain deposits distinguished by their fauna, the Mollusca being especially employed in the identifications. Boulder-clay seems, in this country, to have been taken as the premier indication of the glacial period; it was supposed to be a submarine deposit formed during a submergence of large parts of these islands in the course of that period. That the late Sir Charles Lyell dwelt upon the problems of the boulder clay should also be recalled, for he expressly recounts how constantly it proved a barrier marking the extreme limit to which the works of Man could be traced. Implements or even bones had been found in the drift and above the boulder-clay, but not below.

For a while no attempt seems to have been made to subdivide the boulder-clay or to question its exact identity over all the area occupied by it. Yet such a subdivision might have resulted in explaining the contradiction or paradox (curiously analogous to that propounded by Mr Hinton in 1910, cf. p. 102 supra) just mentioned as existing between the age to be assigned to the Thames river-drift upon (a) stratigraphical evidence (‘post-glacial’), and (b) palaeontological evidence (‘pre-glacial’).

That there might be several deposits of the boulder-clay with intervening strata, does not appear to have been suggested. The Glacial period was long regarded as one and indivisible. By some able geologists that view is still held.

Yet even in those comparatively early days, some succession of glaciations was suspected. In 1845, Ramsay recognised three phases of ice-action in North Wales. In 1855, Morlot took in hand the work of charting the extent of several Swiss glaciations. At last the possibility of a subdivision of the boulder-clay was realised, and it was demonstrated by the researches of Sir A. Geikie[41] (1863). But such division of the boulder-clay leads directly to an inference of successive periods of deposition—and when the earlier opinion (whereby the boulder-clay was regarded as a submarine deposit) was partly abandoned in favour of its origin as a ‘ground-moraine,’ the plurality of glaciations was still more strongly supported. The work of Julien (Auvergne, 1869) and Professor James Geikie (1873) carries the story on to the year 1878 which is marked by a very memorable contribution from Professor Skertchley[42], by whom account was taken of the stratigraphical position of stone implements. The names of these pioneers (and that of Croll should be added to the list) may be fittingly recalled now that the names of later continental observers figure so largely. But the work of Professors Penck, BrÜckner, Boule and Obermaier, admirable as it is, may be regarded justly as an extension or amplification of pre-existing research.

A multiplicity of glaciations demonstrated whether by successive ‘end-moraines,’ or by a series of boulder-clays or ‘tills,’ implies intervening ‘inter-glacial’ epochs. To the earlier-recognised pre-glacial and post-glacial periods, one or more inter-glacial phases must therefore be added. Consequently the absence of evidence (indicative of Man's existence) from the boulder-clay need not exclude his presence in the inter-glacial deposits; and in fact the appearance of strongly-supported evidence that some implements of only Neolithic antiquity occur in inter-glacial surroundings, has been mentioned already (Chapter IV, Sturge, 1909). And thus, whether the series be one of grand oscillations constituting as many periods, or on the other hand a sequence of variations too slight to deserve distinctive terms, the fact of alternations prolonged over a considerable time seems to be established. Attempts to correlate various phases in the history of the animal and particularly of the human inhabitants of the affected area with these changes, still remained to be made.

Of such attempts, an early one, if not absolutely the earliest, stands to the credit of Dr Skertchley (1878). But in 1888 a much more definite advance was made by Professor Boule[43]. Still later came the suggestions of Professors Mortillet, Hoernes[44] (1903), Penck, Obermaier[45] (1909) and Tornqvist. And the employment of implements in evidence was found practicable by them. Ample compensation is thus provided for the lack of human bones, a deficiency almost as deplorable in 1911 as it was when Lyell called attention to it in 1863.

But the literature on this subject is so controversial and has attained such proportions, that the attempt to present current views will be limited to the discussion of the appended table (B). Here an endeavour has been made to submit the views expressed by the most competent observers of the day. The first point to which attention is directed consists in the manner in which the several glacial periods are distributed over the geological time-table. Boule claims one glaciation of Pliocene antiquity, followed by two Pleistocene glaciations. The remaining authors agree in ascribing all the glaciations to the Pleistocene period. Herein they follow the lead of Professor Penck, whose diagram of the oscillations in level of the snow-line in Central Europe is reproduced in Fig. 25. In the next place, the fact that Professor Penck's scheme was primarily intended to serve for the Swiss Alps must not be overlooked. That this system should leave traces everywhere else in Europe is not necessarily implied in accepting the scheme just mentioned.

In attempting to adjust the scale of glacial periods to that provided by the succession of implement-forms, it is suggested that a commencement should be made by considering the period designated Mousterian. If the position of the Mousterian period can be correlated with a definite subdivision of the Ice Age, then other periods will fall into line almost mechanically.

TABLE B

List of types of associated implements.

[1] Penck postulates four glaciations, all “pleistocene.”[2] Boule recognises two pleistocene glaciations (seemingly Nos. III and IV of Penck), and one pliocene glaciation. The latter is not indicated in the Table.[3] Skertchley's scheme is now ignored, if not abandoned, by the best authorities. It has been introduced here on account of its historical interest only. Its correlation with the other schemes is speculative.[4] The differences between the rival schemes of Boule, Penck and Hoernes are best realised by comparing the position assigned to the SolutrÉan industry by each in turn. The lÖss and its divisions are not indicated in this Table.

The first enquiry to make is that indicated in the introductory paragraphs of this Chapter, viz. what is the general nature of the fauna accompanying Mousterian implements? Investigation of the records shews that this is characteristically of a northern or a temperate, but not a southern type. For the combination commonly regarded as indicative of the southern type (viz. Elephas antiquus, Rhinoceros merckii, and Hippopotamus major) is very doubtfully demonstrable in this association, save in the very remarkable instance of the Grotte du Prince, Mentone, and Boule (1906) makes somewhat laboured efforts to explain this example, which is exceptional in his opinion. On the other hand, that combination does occur in well-recognised inter-glacial deposits, e.g. the Swiss Lignites of DÜrnten, etc.

The Mousterian implements commonly accompany much more definitely northern animal forms, so that a glacial rather than an inter-glacial age is indicated. But there are four such glacial phases from which to choose in Professor Penck's scheme, and in Professor Boule's scheme there are two (for the ‘Pliocene glaciation,’ appearing in the latter, is hardly in question).

It will be seen (by reference to Table B) that Professor Boule assigns typical Mousterian implements to the most recent glacial period (Boule's No. III = Penck's No. IV = WÜrm), whereas Professor Penck places them in his penultimate grand period (Riss), carrying them down into the succeeding (Riss-WÜrmian) inter-glacial period.

Much diligence has been shewn in the various attempts to decide between these, the two great alternatives. (The view of Professor Hoernes, who assigns the Mousterian types to the first inter-glacial period of Penck, has received so little support as to render it negligible here.)

Upon an examination of the controversial literature, the award here given is in favour of Professor Boule's scheme. The following reasons for this decision deserve mention.

(1) Almost the only point of accord between the rival schools of thought, consists in the recognition by each side that the Magdalenian culture is post-glacial. But beyond this, the two factions seem to agree that the Mousterian culture is ‘centred’ on a glacial period but that it probably began somewhat earlier and lasted rather longer than that glacial period, whichever it might be.

(2) The Chellean implements, which precede those of Mousterian type, are commonly associated with a fauna of southern affinities. This denotes an inter-glacial period. Therefore an inter-glacial period is indicated as having preceded the Mousterian age. But after the Mousterian age, none of the subsequent types are associated with a ‘southern fauna.’

Indications are thus given, to the following effect. The Mousterian position is such that a distinct inter-glacial period should precede it, and no such definite inter-glacial period should follow it. The last glacial period alone satisfies these requirements. The Mousterian position therefore coincides with the last great glaciation, whether we term this the fourth (with Professor Penck), or the third, with Professor Boule.

(3) The Mousterian industry characterises a Palaeolithic settlement at Wildkirchli in Switzerland: the position of this is indicated with great accuracy to be just within the zone limited by the moraine of the last great glacial period (Penck's No. IV or WÜrmian). The associated fauna is alleged to indicate that the age is not post-WÜrmian, as might be supposed. This station at Wildkirchli probably represents the very earliest Mousterian culture, and its history dates from the last phase of the preceding (i.e. the Riss-WÜrm) inter-glacial period. But it belongs to Penck's glaciation No. IV, not to No. III.

(4) Discoveries of implements of pre-Mousterian (Acheulean) form in the neighbourhood of the ChÂteau de Bohun (Ain, Rhone Basin, France, 1889), and ConliÈge (Jura, 1908) are accompanied by stratigraphical evidence whereby they are referred to an inter-glacial period later than the Riss glaciation (Penck's No. IV, Boule's No. III).

The remaining arguments are directed against the position assigned by Professor Penck to the Mousterian implements.

(5) Professor Penck admits that the epoch of the Mousterian type was glacial, and he recognises that it was preceded by a definitely inter-glacial epoch, with a southern fauna. But by selecting his No. III as the glacial period in question he is led to postulate a subsequent but warmer inter-glacial subdivision of the Mousterian period. The difficulty is to find convincing evidence of this post-Mousterian inter-glacial period, and of the corresponding ‘southern’ fauna. Professor Penck believes that the ‘southern’ animals returned. Professor Boule can find no post-Mousterian evidence of such a fauna. The constituent forms became extinct or migrated southwards, never to return. If this contention be true, and there is much in its favour, Professor Boule's view must be adopted.

To shew how far-reaching some of the discussions are, attention may be directed to the fact that in this particular argument, much turns upon the nature of the implements found with the ‘southern fauna’ at Taubach (v. ante Chapters II and III). If the implements are of Mousterian type, they support Professor Penck's view, for the ‘warm Mousterian’ sought by him will thus be found: but if the type is Chellean, the arguments of Professor Boule are notably reinforced.

(6) The position assigned to one stage in the series of implements will affect all the rest. Professor Penck's view has been attacked with vigour and also with great effect, on account of the position he allots to the type of SolutrÉ. The consensus of opinion regarding the position of SolutrÉ (i.e. its typical implements) is very extensive and quite definite. In effect, the type of SolutrÉ is assigned to the newer (jÜngerer) lÖss deposits. But these are also widely recognised as entirely post-glacial. Moreover in the last few years, the excavations in these particular lÖss-deposits in Lower Austria have not only confirmed that opinion, but have also revealed there the presence of Aurignacian implements, which closely follow those of Mousterian type.

Professor Penck's scheme seems therefore to carry the SolutrÉan implements too far back. The attempt to overcome this objection by attributing an earlier (? inter-glacial) age to the special variety of lÖss in question, has not been attended with conspicuous success.

Such are the main considerations upon which the decision has been taken in favour of Professor Boule's chronological scale. But when such an authority as Professor Sollas[46] (1908) is undecided, an amateur must not attempt to ignore the difficulties to be met. And while it is expedient to arrive at a final judgment, yet, in these controversies, the tendency is very marked to allow theory to run too far ahead of fact. Facts of the following kind are hard to reconcile with the schemes just described. (i) A Mousterian type of implement is recorded by Commont from the later (younger) lÖss of the third terrace at S. Acheul. According to the theory, the type of SolutrÉ, and not of Le Moustier, should have occurred, (ii) In this country at least, an admixture of ‘northern’ and ‘southern’ animals in a single deposit, has been demonstrated not infrequently, as in Italy also (Torre della Scalea, Cosenza). (iii) Professor Boyd Dawkins[47] (1910) insists upon the occurrence of Chellean, Acheulean, and Mousterian implements in one and the same British river deposit.

Consequently the distinction of a northern from a southern fauna may yet prove to be destitute of sound foundations. Many years ago, Saporta pointed out instances of regions with a sub-tropical climate actually adjacent to glacial areas. This subject has fortunately now the advantage of the attention and criticism provided by such talented observers as Mr Hinton, Professor Laville, and Professor Schmidt.

A trustworthy scheme of the relative chronology of culture (as denoted by the forms of implements), of mammalian variation and evolution (as shewn by the fauna), and of great climatic oscillations has not yet been obtained, but it has not been shewn to be unattainable. Meanwhile the schemes outlined in Table B mark a very great advance upon their predecessors.

It may be of interest to note that Professor Penck believes that the several periods varied both in duration and in intensity. Their relative proportions are shewn in Professor Penck's diagram (Fig. 25). The smaller oscillations, following the close of the last great glaciation (WÜrmian), should be noticed.