The second glaciation was by far the greatest both in Europe and America. In the region of the Pyrenees, which at the very much later period of the Third Interglacial Stage became a favorite country with Palæolithic man, there were glaciers of vast extent. This is realized by comparison with present conditions. The largest of the present glaciers of the Pyrenees is only 2 miles in length and terminates at a height of 7,200 feet above the sea. During the greatest glaciation the snow appears to have descended 4,265 feet below its present level. From the Pyrenees through the Gallego valley into Spain there flowed a glacier 38 miles in length, while to the north the glacier in the valley of the Garonne flowed for a distance of 45 miles to a point near Montréjeau. Even in its lower reaches this glacier was over half a mile in thickness. To the east was a glacier 38 miles in length, filling the valley of the Ariège and covering the sites of such great Palæolithic caverns as that of Niaux; it is probable that at this time the formation of this cavern began. That these glaciers were all prior to the period of the Lower Palæolithic Acheulean culture is proven by the fact that Acheulean implements are frequently met with lying on the surface of the moraines laid down by these ancient ice-floes.(33)

To the north was the vast Scandinavian ice-field, which swept over Great Britain and beyond the valleys of the Rhine, Elbe, and Vistula, reaching nearly to the Carpathians. Even the lesser mountain chains were capped with glaciers, including the Atlas Mountains in northern Africa.

In North America from the great centre west of Hudson Bay the ice-cap extended its drift southward into Missouri, Iowa, Kansas, and Nebraska, beyond the limits of earlier and subsequent glaciations.

The materials of the chief 'high terraces' of the great river-valleys of western Europe were deposited at this time.

Life of the Warm Second Interglacial Stage

The long warm period which followed the great glaciation is remarkable in presenting the first proofs of the presence of man in western Europe. It is the period of the Heidelberg race of man (Homo heidelbergensis), known only from a single jaw discovered by Schoetensack in the Mauer sands near Heidelberg, in 1907. No other proofs of the existence of man have been found in any of the deposits which took place during this vast interval of geologic time, unless we accept the theory of Penck and of Geikie that the Pre-Chellean and Chellean quarries of the River Somme belong in the Second Interglacial Stage.

The vast duration of this interglacial time is evidenced both in Europe and America by the deep cutting and wearing away of the 'drifts' brought down by the second glaciation. Penck believes that this 'long warm stage' represents a greater period of time than the entire interval between the third glaciation and the present time. The climate immediately following the retreat of the glaciers was cool and moist in the glaciated regions, but this was followed by such a prolonged period of heat and dryness that the glaciers on the Alps withdrew to a point far above their present limits.

In one of the old 'high terraces' of the River Inn, in the north Tyrol, is a deposit containing the prevailing forest flora of the period, from which Penck concludes that the climate of Innsbruck was 2° C. higher than it is at the present time. Corresponding with this the snow-line stood 1,000 feet above its present level, and the Alps, save for the higher peaks, were almost completely denuded of ice and snow. A characteristic plant is the Pontic alpine rose (Rhododendron ponticum), which flourishes now in an annual temperature of 57°-65° Fahr.,(34) indicating that the climate of Innsbruck was as genial as that of the Italian slopes of the Alps to-day. This rhododendron is now found in the Caucasus. Other southern species of the time were a buckthorn, related to a species now living in the Canary Islands, and the box. There were also more hardy plants, including the fir (Pinus sylvestris), spruce, maple, willow, yew, elm, beech, and mountain-ash. The forests of the same period in Provence were, for the most part, similar to those now found in that region; out of thirty-seven species twenty-nine still occur in this part of southern France. On the whole, the aspect of southern France at this time was surprisingly modern. The forests included oaks, elms, poplars, willows, lindens, maples, sumachs, dogwood, and hawthorn. Among the climbing plants were the vine and the clematis. Here also were some forms which have since retreated to the south, such as species of the sweet bay and laurel which are now confined to the Canary Islands. The great humidity of the time is indicated by the presence of certain species of conifers which require considerable moisture. As in First Interglacial times, the presence of the fig indicates mild winters.

It is difficult to imagine forests of this modern character, which farther northward included a number of still more temperate and hardy species, as the setting of the great African and Asiatic life that roamed all over western Europe at this time. It was the presence of hippopotami, elephants, and rhinoceroses which gave to Lyell, Evans, and other early observers the impression that a tropical temperature and vegetation were characteristic of this long life period. These animals were formerly regarded as proofs of an almost tropical climate, but the more trustworthy evidence of the forests, strengthened by that of the presence of very numerous hardy types of forest and meadow animals, has set aside all the early theories as to extremely warm temperatures during Second Interglacial times.

The remains of what is still conveniently known as the 'faune chaude,' or warm fauna, are chiefly found in the sands and gravels of the ancient beds of the Neckar, Garonne, and Thames, and other rivers of the north and south, also in Essex, England. The most surprising fact is that the mammal life of western Europe remained entirely unchanged by the vast second glaciation just described; the few extinctions which occurred as well as a number of new arrivals may be attributed to new geographical connections with Africa on the south and to the steady progress of migration from the far east.

There were four very important and distinctive new arrivals from the African-Asiatic world, namely, the straight-tusked or ancient elephant (E. antiquus), the broad-nosed rhinoceros (D. merckii), the African lion (Felis leo), and the African hyæna (H. striata), which bespeak close geographical connections with northern Africa. Of these the ancient elephant and the broad-nosed rhinoceros were close companions; they enjoyed the same regions and the same temperatures, their remains are very frequently found together, and they survived to the very end of the great life stage of western Europe, which closed with the advent of the fourth glaciation. They are in contrast to the other pair of great mammals which was already present in Europe in Pliocene and First Interglacial times, namely, the southern mammoth, at this stage known as Elephas trogontherii, which had a preference for the companionship of the hippopotamus (H. major); it would seem that these animals were less hardy because both disappeared from Europe a little earlier than the ancient elephant and Merck's rhinoceros.

The African lion would appear to have been a competitor of the sabre-tooth tiger, for the latter animal now becomes less abundant, although there is reason to believe that it survived until the Third Interglacial Stage. With the ancient Pliocene type of the sabre-tooth were also found the Etruscan rhinoceros, the primitive bear of Auvergne (Ursus arvernensis), and the giant beaver (Trogontherium cuvieri).

The northern forests of the time were frequented by the broad-faced moose, the giant deer, and the roe-deer, as well as by noble specimens of the stag (Cervus elaphus). In the open forests and meadows the wild cattle (Bos primigenius) began to be more numerous and the bison (Bison priscus) also occurred. Among the meadow or forest frequenting forms were horses of larger size, such as the horses of Mosbach and of Süssenborn. In this assemblage of northern and southern types it is noteworthy that the Eurasiatic forest and meadow types of mammals greatly predominate in numbers and in variety over the African-Asiatic types; this, together with the flora, is an indication that the climate was of a temperate character; it is probable, therefore, that all the mammals were well protected with a hairy covering and adapted to a temperate climate. The fact that the fauna as a whole remained practically unchanged throughout the second glaciation is a proof not that it migrated to the south and then returned but that the non-glaciated regions of western Europe were temperate rather than cold.

The Heidelberg Race

Heidelberg man.
Ancient elephant.
Etruscan rhinoceros.
Mosbach horse.
Wild boar.
Broad-faced moose.
Red deer, or stag.
Roe-deer.
Primitive bison (wisent).
Primitive ox (Aurochs, urus).
Auvergne bear.
Deninger's bear.
Lion.
Wildcat.
Wolf.
Beaver.

To us by far the most interesting mammalian life is that found south of the mouth of the Neckar along the ancient stream Elsenz, where were deposited the lower 'sands of Mauer,' containing the lower jaw of the Heidelberg man and the remains of many animals of the period. The enumeration of this entire fauna is very important, as indicating the temperate climatic conditions which surrounded the first true species of man which has thus far been discovered in Europe. The discoverer, Schoetensack,(35) referred these mammals and the Heidelberg man to the First Interglacial Stage, and a similar opinion has recently been expressed by Geikie. The presence of the Etruscan rhinoceros would appear to point to such great antiquity, but the evidence afforded by this primitive animal is overborne by that of three mammals which are highly characteristic of Second Interglacial times; these are the straight-tusked or ancient elephant (E. antiquus), the lion, and the Mosbach horse. Excepting only the Etruscan rhinoceros, all these species frequenting the ancient stream Elsenz and deposited with the 'sands of Mauer' occurred also in the forests and meadows of the region now known as Baden, where the fossil mammal deposits of Mosbach near the Neckar are found. A similar mammalian life of a somewhat more recent time occurs in the river gravels of Süssenborn, near Weimar. The horses of Mauer, of Mosbach, and of Süssenborn[Q] were of much larger size and of more specialized character than Steno's horse of First Interglacial times.

Thus the Heidelbergs, the first human race recorded in western Europe, appear in northern Germany early in Second Interglacial times, in the midst of a most imposing mammalian fauna of northern aspect and containing many forest-living species, such as bear, deer, and moose; in the meadows and forests browsed the giant, straight-tusked elephant (E. antiquus), which from the simple structure of its grinding-teeth is regarded as similar in habit to the African elephant now inhabiting the forests of central Africa; the presence of this animal indicates a relatively moist climate and well-forested country. The Etruscan rhinoceros differed from the larger Merck's form in the possession of relatively short-crowned grinding-teeth, adapted to browsing habits and a forested country; on the head were borne two horns; it was a long-limbed, rapidly moving type; the herds of bison and of wild cattle (urus) which roamed over the plains were now subject to the attack of the lion.

Fig. 47. The Heidelberg jaw, type of Homo heidelbergensis.
About two-thirds life size. After Schoetensack.

The discovery in 1907 of a human lower jaw in the base of the 'Mauer sands' is one of the most important in the whole history of anthropology. The find was made at a depth of 79 feet (24.10 m.) from the upper surface of a high bluff (Fig. 46), in ancient river sands which had long been known to yield the very old mammalian fauna described above. For years the workmen had been instructed to keep a sharp lookout for human remains. The jaw had evidently drifted down with the river sands and had become separated from the skull, but it remained in perfect preservation. The author's description may first be quoted.(36) The mandible shows a combination of features never before found in any fossil or recent man. The protrusion of the lower jaw just below the front teeth which gives shape to the human chin is entirely lacking. Had the teeth been absent it would have been impossible to diagnose it as human. From a fragment of the symphysis of the jaw it might well have been classed as some gorilla-like anthropoid, while the ascending ramus resembles that of some large variety of gibbon. The absolute certainty that these remains are human is based on the form of the teeth—molars, premolars, canines, and incisors are all essentially human and, although somewhat primitive in form, show no trace of being intermediate between man and the anthropoid apes but rather of being derived from some older common ancestor. The teeth, however, are somewhat small for the jaw; the size of the border would allow for the development of much larger teeth; we can only conclude that no great strain was put on the teeth, and therefore the powerful development of the bones of the jaw was not designed for their benefit. The conclusion is that the jaw, regarded as unquestionably human from the nature of the teeth, ranks not far from the point of separation between man and the anthropoid apes. In comparison with the jaws of Neanderthal races, as found at Spy, in Belgium, and at Krapina, in Croatia, we may consider the Heidelberg jaw as pre-Neanderthaloid; it is, in fact, a generalized type.

In a conservative spirit, Schoetensack named the type represented by this jaw Homo heidelbergensis. Other authors have regarded it as of distinct generic rank; thus it has been termed Palæoanthropus heidelbergensis by Bonarelli.(37) The jaw itself is extremely massive; the canine teeth, unlike those of the anthropoid apes and of the Piltdown race, do not project beyond the line of the other teeth and were therefore not used as weapons of offense and defense as in the anthropoids, in which these teeth are prominently developed as tusks. As noted by Schoetensack, the teeth are not very massive in proportion to the jaw itself, which is the most powerful human jaw known, even exceeding the largest Eskimo jaw and indicating a skull of very massive and primitive character. It resembles that of the ape in the recession of the chin, hence it has been termed amentalis. There is a large development of the coronoid process of the mandible for the attachment of the temporal muscle. This jaw may well have been used as a tool in the last stages of the preparation of hides, as is the practice of the Eskimo races. We observe that the powerful bony branches of the jaw, when regarded from above, close in upon the space left for the tongue; in fact, the bone closes in to such an extent as to interfere seriously with the free use of the tongue in articulate speech.

It would seem that in the jaw, and probably in all other characters of the skull, as they become known, the Heidelberg race will be found to be a Neanderthal in the making, that is, a primitive, more powerful, and more ape-like ancestral form. In the matter of the retreating chin, the true Neanderthals of Spy, Malarnaud, Krapina, and La Chapelle rank exactly half-way between the most inferior races of recent man and the anthropoid apes.

Not only among the Eskimos, but generally throughout the savage races of Australia and of other countries, the jaws are used as tools; among the Australians the teeth are very much worn down but are in admirable preservation. When seen from above, we observe that the 'Heidelberg' grinding-teeth form a perfect arch, or horseshoe-shaped arrangement, whereas in all the apes the two lines of grinding-teeth are almost parallel with each other. Thus, while there may be wide differences of opinion as regards the relationships of the Heidelberg man, all agree that Schoetensack's discovery affords us one of the great missing links or types in the chain of human development.

The typical mammalian life of Second Interglacial times as found at Mosbach and Süssenborn belongs perhaps to a somewhat more recent stage of Second Interglacial times than that of the 'Mauer sands,' for in these localities the Etruscan rhinoceros is wanting and the more specialized broad-nosed rhinoceros is abundant; this animal differs from the Etruscan form in the possession of relatively long-crowned grinding-teeth, which were better adapted to grazing habits. On the head were borne two horns. A variety of the southern mammoth (E. trogontherii) is so highly characteristic of Second Interglacial times that Pohlig refers to this life period as the E. trogontherii stage. From the structure of its grinding-teeth it is regarded as similar in habit to the Asiatic elephant, which now inhabits the forests of India, but it has the peculiar concave forehead distinctive of the mammoth and quite unlike the convex forehead of the Indian elephant. The bears of this period belong to the primitive species U. deningeri and U. arvernensis, for so far there is no certain record of the presence of the true brown bear of Europe (U. arctos). The sabre-tooth tiger of this time is preserved in the caverns of the Pyrenees near Montmaurin, associated with the remains of the striped hyæna (H. striata), a species which was widely distributed over western Europe in early Pleistocene times. This species was contemporary with, and later replaced by, the spotted hyæna (H. crocuta), from which the very hardy cave-hyæna (H. crocuta spelæa) of the 'Reindeer Period,' descended. We observe that the 'polycladine' deer of Upper Pliocene and First Glacial times has disappeared from western Europe; nor are there any traces of the axis deer. The hippopotamus is still represented by the giant species, H. major.

Early Northern Migrations of the Reindeer

The animals that we have described belong in the warmer and more temperate regions of Europe. In the regions near the glaciers the reindeer was already to be found; in fact, this characteristically northern animal is recorded in the gravels of Süssenborn, near Weimar.

There is evidence of a succession of climatic changes in the region of Heidelberg. The Heidelberg jaw with its temperate mammalian fauna occurred at the very base of the Mauer bluff, but higher up the bluff (Fig. 46) on a corresponding level are found the remains of mammals which indicate a marked lowering of temperature and which are referred by some authorities to the period of chilling climate that characterized northern Europe toward the close of Second Interglacial times. The reindeer also occurs in the 'high terrace' gravels of the River Murr, near Steinheim; thus, at Mauer, at Süssenborn, and at Steinheim, we find proof that the reindeer had begun to spread over the colder regions of Europe, and there is some ground for belief that it found its way even as far south as the Pyrenees.

The evidence of the first cold, arid period which for the time greatly affected the climate of western Europe is also found in the layer of so-called 'ancient loess' which lies in the bluff above the 'sands of Mauer.' This loess covers the warm mammalian deposits of the 'sands of Mosbach' as well as the 'high terraces' of many of the ancient river-valleys. Both in Europe and America the climatic sequence of the Second Interglacial Stage from moist to dry appears to have been the same.

Thus, after the recession of the ice-fields of the second glaciation, the climate was at first cold and moist; then followed a long warm stage, favorable to the spread of forests; this was finally succeeded by a period of aridity in which the most ancient 'loess' deposits occurred. In Russia, also, the third glaciation was preceded by an arid and steppe-like climate with high winds favorable to the transportation of 'loess.'

No palæoliths or other proofs of human occupation have been found in this cold, dry period, for there is no evidence in any part of Europe of camping stations in this 'ancient loess' such as we find in the 'loess' which was deposited during the similar arid period toward the close of Third Interglacial and again during Postglacial times. Nor have we any record of the mammalian life in this 'ancient loess' of Europe.

The Third Glaciation[R]

This arid period in northern Europe and in North America was followed by the moist, cool climate of the third glaciation. It is estimated by Penck that the advance of these new ice-fields began 120,000 years ago and that the period of advance and retreat of the glaciers was not less than 20,000 years. In the Alps the snow-line descended 1,250 metres below the present level; consequently this glaciation was more severe than the first but somewhat less severe than the second. In northern Europe the Scandinavian ice-field did not cover so wide an area as during the second glaciation, although Britain and Scandinavia were again deeply buried by ice; the glacial cap and glaciers flowed in a westerly and southwesterly direction across Denmark and the southern portion of the basin of the Baltic into Holland and northern Germany. In the Alps the third glaciation sent vast ice-floes along the valley of the Rhine, into eastern France, and into the valley of the Po, where this glaciation was even more extensive than the second. But the greatest glacier of this time was that of the Isar, a southern tributary of the Danube, which rises in the Bavarian Alps.(38)

During the Third Glacial Stage certain of the 'middle terraces' along the Rhine and other rivers flowing from the Alps were formed. In Britain,(39) whereas during the second glaciation the ice-fields extended as far south as the Thames, during the third glaciation they did not extend beyond the midlands; yet an arctic climate prevailed over southern England, with tundra conditions and temperature, as indicated by the plant deposits at Hoxne(40) in Suffolk. Even before the third glaciation began in Europe a great ice-cap had formed over Labrador, on the eastern coast of North America, and the ice-sheets flowing to the south and southwest extended as far as Illinois, depositing the great Illinoian 'drifts.'

Along the borders of these great ice-fields in both countries a cold and moist climate prevailed, for a prime condition of glaciation is the heavy precipitation of snow. In northern Europe, between the great Alpine and Scandinavian ice-fields of the third glaciation a cold climate undoubtedly prevailed; in the region of the Neckar River, near Cannstatt, is found a deposit known as 'mammoth loam,' which Koken believed to be contemporaneous with the period of the third glaciation, although the evidence is certainly not convincing.(41) Here are found fossil remains of the Scandinavian reindeer, also of two very important new arrivals in Europe from the tundra regions of the far northeast, animals which had wandered along the southern borders of the Scandinavian ice-sheet from the tundras of northern Russia and Siberia. This is the first appearance in western Europe of the woolly mammoth (E. primigenius) and the woolly rhinoceros (D. antiquitatis). In this 'mammoth loam' there also occur two species of horse, the giant deer (Megaceros), the stag, the wisent, and the Aurochs. If the woolly mammoth and the woolly rhinoceros actually entered eastern Germany at this time, they certainly retreated to the north with the approach of the warm temperate climate of the Third Interglacial Stage, because no trace of these animals has been found again in Europe until the advent of the fourth glaciation.

CHAPTER II

Penck estimated that the third warm interglacial stage[S] opened about 100,000 years ago and lasted between 50,000 and 60,000 years. According to the theory that we have adopted in this work, the Third Interglacial and Fourth Glacial embraced the entire period of Lower Palæolithic time, a period of from 70,000 to 100,000 years, much longer than that of Upper Palæolithic time, which is estimated at 16,000 to 25,000 years.

Geologic Antiquity of the Beginning of the Stone Age

Attention should first be called to the fact that, preceding the epoch we have now entered, the glacial and interglacial forces operating over the great peninsula of western Europe had left their impress chiefly on the glaciated areas and only to a minor degree on the free, non-glaciated areas. Until toward the close of Third Interglacial times no traces of northern much less of arctic forests and animals are discovered anywhere, except along the borders of the ice-fields. It would appear as if the animal and plant life of Europe were, in the main, but slightly affected by the first three glaciations. We cannot entertain for a moment the belief that in glacial times all the warm flora and fauna migrated southward and then returned, because there is not a shred of evidence for this theory. It is far more in accord with the known facts to believe that all the southern and eastern forms of life had become very hardy, for we know how readily animals now living in the warm earth belts are acclimatized to northern conditions.

If, on the other hand, we depend solely on the testimony of the life conditions, we might conclude that the Pre-Chellean flint workers reached western Europe either in Second Interglacial times, or during the third glaciation, or again during Third Interglacial times. Let us consider this evidence of the fossil mammals more closely.

In favor of the theory that the Pre-Chellean culture is as ancient as Second Interglacial times, we should consider the fact that in several localities palæoliths of Pre-Chellean if not of Chellean type have been recorded in association with the remains of a number of the more primitive mammals which we have described above as characteristic of Second Interglacial times. For example, at Torralba, Province of Soria, Spain, there has been discovered(1) an old typical Chellean camp site, containing abundant remains of the broad-nosed rhinoceros and of the southern mammoth, mingled with the remains of other mammals of very ancient type, identified as the Etruscan rhinoceros and as Steno's horse. Again, along the River Somme, near Abbeville, in the gisement du Champ de Mars,(2) it is said that Pre-Chellean and Chellean implements have been found in association with the Etruscan rhinoceros, Steno's horse, and very numerous specimens of the sabre-tooth tiger and of the striped hyæna. Moreover, in Piltdown, Sussex, Pre-Chellean flints and the Piltdown skull are said to have occurred in a layer containing a rhinoceros which may be identified with the Etruscan. If these very ancient species of animals are rightly recognized and determined, and if they are truly found as reported in close association in the same layers with Pre-Chellean and Chellean flints, the evidence may be considered as quite strong that the beginning of Chellean culture dates from Second Interglacial times; unless, indeed, it should prove that these primitive species of mammals survived into Third Interglacial times in certain favored districts. We should also consider the possibility that these more ancient animals, the sabre-tooth tiger, Steno's horse, the Etruscan rhinoceros, and the giant beaver, did not really belong in the same layer with these old palæoliths but were accidentally washed into this layer from other more ancient deposits. As a rule, it is the most recent animals which establish a prehistoric date, because we know that a palæolith cannot be older than the most recent mammal with which it occurs.

The record of the three early glaciations is not fully written in the animal and plant life, but it appears to be found in the river channels. Both in England and France these channels attest flooded conditions during the earlier glaciations, in which large quantities of gravels and sands were transported, and it is of these materials that the 'high terraces' were built up. It is chiefly the geologic evidence which establishes the Pre-Chellean date.

Geologic and climatic lines of evidence in France indicate that the Pre-Chellean culture is first witnessed during the beginning of Third Interglacial times. This is the opinion of Boule, Haug, Obermaier, Breuil, Schmidt, and many other geologists and archæologists. That the first Palæolithic flint workers found their way into western Europe during the early part of Third Interglacial times is consistent with our observations on the sequence of climate, on the formation of the 'low river terraces,' where palæoliths of the earliest type occur, as well as with the general succession of mammalian life throughout the climatic changes of this interglacial period. It would appear, in explanation of the facts cited above regarding the fossil mammals, that when the Pre-Chellean flint workers established their camps along the valley of the River Somme in northern France a very genial climate prevailed in this region, favorable even, as we shall see, to the survival of some of the Pliocene types of mammals, such as the sabre-tooth tiger and the Etruscan rhinoceros.

During the early part of the Third Interglacial Stage the climate, so far as we can judge by the unchanged aspect of the animal life, remained of the same warm temperate character. Two only of the surviving Pliocene forms, namely, the sabre-tooth tigers and the Etruscan rhinoceroses, became rare or extinct. From evidence afforded in Kent's Hole, Devonshire, Dawkins is led to believe that the sabre-tooth tiger survived in Britain until Postglacial times. All the rest of the animal world, both the African-Asiatic and the Eurasiatic mammals, continued to flourish throughout western Europe.

Not until the latter part of Acheulean times do we discover proofs of a decided change of climate; in the approach of arid conditions similar to those of the steppes of western Asia there was a renewal of the great dust-storms and depositions of 'loess,' such as had previously occurred toward the close of Second Interglacial times; this was followed by the still colder climate of the fourth glaciation, which corresponds with the closing period of Lower Palæolithic culture.

The evolution of the Pre-Chellean into the Chellean and finally into the Lower Acheulean palæoliths certainly occupied a very long period of time if we assign it merely the 50,000 or 60,000 years allotted to the Third Interglacial; but even this allotment seems far too long when we observe the relatively limited depth of the river deposits in which these flint cultures succeed each other. For we cannot fail to be impressed by the regular and very close and unbroken succession of the geologic layers containing the Chellean and Acheulean artifacts. (See Fig. 55.)

None the less it follows that a long lapse of time must be allowed for each culture period, and for the advance in technique.(3) It is this wide distribution that has enabled the de Mortillets (father and son), Capitan, Rivière, Reboux, Daleau, Peyrony, Obermaier, Commont, Schmidt, and others to establish in various parts of Europe the main stages of the industrial evolution of the Old Stone Age, or Lower Palæolithic.