The forests and river borders of the valley of the Arno, near Florence, contained all these African-Asiatic animals in Upper Pliocene times. Here they received their names which remind us of this region of Italy as it is to-day, such as the Etruscan rhinoceros (Dicerorhinus etruscus), the Florentine macaque (Macacus florentinus), Steno's horse (Equus stenonis), the Etruscan cattle (Leptobos etruscus), which was the earliest ox to reach Europe.

In Italy and France these African-Asiatic mammals were mingled with ancestors of the more hardy Eurasiatic forest and meadow group. Of these the most graceful were a variety of deer with very elaborate or many-branched antlers, hence known as the 'polycladine' deer. In the forests roamed the wild boars of Auvergne (Sus arvernensis), also the bears of Auvergne (Ursus arvernensis), lynxes, foxes, and wildcats. In the rivers swam the otter and the beaver, closely allied to existing forms. Among the rocks of the high hills were the pikas or tailless hares (Lagomys), also hamsters, moles, and shrews.

Many of the most characteristic animals of the dry modern plateaus of Africa had disappeared from Europe before the close of Pliocene times, namely, species of gazelles, antelopes, and the hipparion horses, all of which were adapted to the dry uplands or deserts of Africa. In the remaining faune Pliocène récente of French authors we find evidence that the Pliocene in all of western Europe closed with a moist, warm, temperate climate, with wide-spread forests and rivers interspersed with meadows favorable to the life of a great variety of browsing deer as well as of grazing elephants, horses and cattle. The flora of the Middle Pliocene as found at Meximieux indicates a mean annual temperature of 62° to 63° Fahr.

One of the proofs of the gradual lowering of temperature toward the close of Pliocene times in Europe is the southward retreat and disappearance of the apes and monkeys; the Upper Miocene gibbon is found as far north as Eppelsheim, near Worms, Germany; in Lower Pliocene times the monkeys and apes are found only in the forests of the south of France; in Upper Pliocene times they are recorded only in the forests of northern Italy; the evidence, so far as it goes, indicates a gradual retreat toward the south.

Finally, at the end of the Pliocene there existed very close geographic relations eastward with the mammalian life of India by way of what was then the isthmus of the Dardanelles and southward with the mammalian life of Africa by way of the Sicilian land bridge. This would indicate that the long lines of eastward and westward migration were open and favorable to the arrival in western Europe of new migrants from the far east, including perhaps the most primitive races of man. There is not the least evidence that Pliocene man or ancestors of man existed in Europe, excepting such as may be afforded by the problematic eoliths, or most primitive flints.

The First Glaciation

In Upper Pliocene times cold marine currents(6) from the north began to flow along the southeastern coast of England, with indications of a gradually lowering temperature culminating at a time when the sea abounded in the arctic mollusks, which have been preserved in the 'Weybourn Crags,' a geologic formation along the coast of Norfolk. This arctic current was the herald of the First Glacial Stage.

It does not appear that a glacial cap of any considerable extent was formed in Great Britain at this stage, but about this time the first great ice-cap was formed in British North America west of Hudson Bay, which sent its ice-sheets as far south as Iowa and Nebraska. In the latter State forests of spruce and other coniferous species indicate the appearance of a cool temperate flora in advance of the glaciation. In the Swiss Alps the snow descended 1,200 meters below the present snow-line, and in Scandinavia and northern Germany the first great ice-sheets were formed from which flowed the glaciers and rivers conveying the 'Old Diluvium,' or the 'oldest drift.' Accompanying the cold wave along the eastern coast of England we note, in the famous fossil deposits known as the 'Forest Bed of Cromer,' which overlie the Weybourn Crags, the arrival from the north of the fir-tree (Abies). This is most significant, because it had hitherto been known only in the arctic region of Grinnell Land, and this was its first appearance in central Europe. Another herald of northern conditions was the first occurrence of the musk-ox in England, which is attributed(7) to the 'Forest Bed' deposits.

While Great Britain was less affected at this time than other regions, there is no doubt as to the vast extent of the First Glacial Stage in British America, in Scandinavia, and in the Alps; in the latter region it has been termed 'the Günz stage' by Penck and Brückner. The 'drift' deposits have a general thickness of 98½ feet (30 m.), but they are largely covered and buried by those of the far more extensive Second Glacial Stage. The Scandinavian ice-sheet(8) not only occupied the basin of the Baltic but overflowed Scania—the southern part of Sweden—and extended as far south as Hamburg and Berlin. In the Alps the glaciers passed down all the great mountain valleys to the low grounds of the foreland, implying a depression of the snow-line to 4,000 feet below its present level.

The First Interglacial Stage. Eoliths

Proofs that a prolonged cool wave passed over Britain during the first glaciation are seen in its after effects, namely, in the modernization of the forests and in the disappearance both in Britain and France of a very considerable number of animals which were abundant in Upper Pliocene times. Yet by far the greater part of the Pliocene mammal life survived, a fact which tends to show that, while very cold conditions of climate and great precipitation of moisture may have characterized the regions immediately surrounding the ice-fields, the remainder of western Europe at most passed through a prolonged cool period during the climax of the First Glacial Stage. This was followed during the First Interglacial by the return of a period somewhat warmer than the present.

This First Interglacial Stage is known as the Norfolkian, from the fact that it was first recognized in Europe in the deposits known as the 'Forest Bed of Cromer,' Norfolk, which contain rich records not only of the forests of the period, but of the noble forms of mammals which roamed over Great Britain and France in Norfolkian times. The forests of Norfolk, in latitude 52° 40' N. mainly abounded in trees still indigenous to this region, such as the maple, elm, birch, willow, alder, oak, beech, pine, and spruce, a forest flora closely corresponding to that of the Norfolk and Suffolk coasts of England at the present time, although we find in this fossil flora several exotic species which give it a slightly different character.(9) From this tree flora Reid concludes that the climate of southeastern England was nearly the same as at present but slightly warmer.

We note especially that a very great change had taken place in the entire disappearance in these forests of the trees which in Pliocene times were common to Europe and America, as described above; in other words, the flora of Europe was greatly impoverished during the first cold wave.

In southern France, as at the present time, the interglacial climatic conditions were milder, for we find numerous species of plants, which are now represented in the Caucasus, Persia, southern Italy, Portugal, and Japan. Thus the First Interglacial Stage, which was a relatively short one, enjoyed a temperature now belonging about 4° of latitude farther south.

This First Interglacial Stage is also known as the St.-Prestien, because among the many localities in France and Italy which preserve the plant and mammal life of the times that of St. Prest, in the Paris basin, is the most famous. Here in 1863 Desnoyers(10) first reported the discovery of a number of mammal bones with incision lines upon them, which he considered to be the work of man. These deposits were regarded at the time as of Pliocene age, and this gave rise immediately to a wide-spread theory of the appearance of man as early as the Pliocene. The human origin of the incisions discovered by Desnoyers has long been a matter of dispute and is now regarded as very improbable. Similar lines may be of animal origin, namely, marks left by claws or teeth, or due to accidental pressure of sharp cutting surfaces. However, we do not pretend to express an opinion of any value as to the cause of these incisions. Supposed confirmation of the evidence of Desnoyers of the existence of Pliocene man was the alleged finding by Abbott of several worked flints, two in situ, in the 'Forest Bed of Cromer,' Norfolk. Many years later in similar deposits at St. Prest were discovered the supposed 'eoliths' which have been referred to the Étage Prestien by Rutot. The age of the St. Prest deposits is, therefore, a matter of the very highest interest and importance.

St. Prest is not Pliocene; it is rather the most ancient Pleistocene deposit in the basin of Paris,(11) and these incised mammal bones probably date from the First Interglacial Stage. The bed which has yielded the incised bones and the rich series of fossils consists of coarse river sands and gravels, forming part of a 'high terrace,' 98½ feet (30 m.) above the present level of the river Eure. This, like other 'high terraces,' contains a characteristic First Interglacial fauna, including the southern mammoth (E. meridionalis), and Steno's horse (E. stenonis). We also find here other very characteristic early Pleistocene mammals, such as the Etruscan rhinoceros (D. etruscus), the giant hippopotamus of early Pleistocene times (H. major), the giant beaver of the early Pleistocene (Trogontherium), three forms of the common beaver (Castor), and one of the bison (Bison antiquus). This mammalian life of St. Prest is very similar to that of Norfolk, England; to that of Malbattu in central France, Puy-de-Dôme; of Peyrolles, near the mouth of the Rhône, in southern France; of Solilhac near Puy; of Durfort, Gard; of Cajarc, Lot-et-Garonne; and finally to that of the valley of the Arno, in northern Italy.

One reason why certain authors, such as Boule and Depéret, have placed this stage in the Upper Pliocene is that the mammals include so many surviving Pliocene forms, such as the sabre-tooth tigers (Machærodus), the 'polycladine' deer with the elaborate antlers (C. sedgwicki), the Etruscan rhinoceros, and the primitive Steno's horse. But we have recently discovered that, with the exception of the 'polycladine' deer, these mammals certainly survived in Europe as late as the Second Interglacial Stage, and there is said to be evidence that some even persisted into the Third Interglacial Stage.

It is, therefore, the extinction or disappearance from Europe of many of the animals very abundant even in late Pliocene times which marks this fauna as early Pleistocene. Anthropoid apes are no longer found; indeed, there is no evidence of the survival of any of the primates, except macaques, which survive in the Pyrenees to late Pleistocene times; the tapir has entirely disappeared from the forests of Europe; but the most significant departure is that of the mastodon, which is believed to have lingered in north Africa and which certainly survived in America into very late Pleistocene times. The animal life of western Europe, like the plant life, has lost one part of its Pliocene aspect while retaining another part, both in its mammalian fauna and in its forest flora.

The living environment as a whole, moreover, takes on a novel aspect through the arrival, chiefly from the north, of the more hardy animals and plants which had been evolving for a very long period of time in the temperate forests and meadows of Eurasia to the northeast and northwest. From this Eurasiatic region came the stag, or red deer (Cervus elaphus), also the giant deer (Megaceros), and from the northerly swamps the broad-headed moose (Alces latifrons). The presence of members of the deer family (Cervidæ) in great numbers and representing many different lines of descent is one of the most distinctive features of First Interglacial times. Beside the new northerly forms mentioned above, there was the roe-deer (Capreolus), which still survives in Europe, but there is no longer any record of the beautiful axis deer (Axis), which has now retreated to southern Asia. The 'polycladine' deer, first observed in the valley of the Arno, is represented in First Interglacial times by Sedgwick's deer (C. sedgwicki), in Norfolk, and by the species C. dicranius of northern Italy, where there also occurs the 'deer of the Carnutes' (C. carnutorum).

We observe that browsing, forest-living, and river-living types predominate. Among the forest-frequenting carnivores were the wolverene, the otter, two kinds of bear, the wolf, the fox, and the marten; another forest dweller was a wild boar, related to the existing Sus scrofa of Europe.

Thus in the very beginning of Pleistocene times the forests of Europe were full of a wild life very similar to that of prehistoric times, mingled with which was the Oriental element, the great elephants, rhinoceroses, and hippopotami connecting Europe with the far east. Among these eastern migrants in the early Pleistocene were two new arrivals, the primitive wild cattle (Bos primigenius), and the first of the bison (Bison priscus).

The theoretical map of western Europe during First Interglacial times (Fig. 12, also Fig. 56) enables us to understand these migrations from the northeast and from the Orient. As indicated by the sunken river channels discovered on the old continental shelf, the coast-line extended far to the west to the borders of the continental plateau which is now sunk deep beneath the ocean; the British Isles were separated from France not by the sea but by a broad valley, while the Rhine, with the Thames as a western tributary flowed northward over an extensive flood-plain, which is the present floor of the North Sea basin.(12) It is not improbable that the rich mammalian life deposits in the 'Forest Bed of Cromer,' Norfolk, were washed down by tributaries of this ancient Rhine River.

In all the great rivers of this enlarged western Europe occurred the hippopotami, and along the river borders and in the forests browsed the Etruscan rhinoceros. Among the grazing and meadow-living forms of the Norfolk country of Britain were species of wild cattle (Bos, Leptobos), together with two species of horses, including a lighter form resembling Steno's horse (E. stenonis cocchi) of the Val d'Arno and a heavier type probably belonging to the forests. The giant elephant of this period is the southern mammoth (E. meridionalis trogontherii), a somewhat specialized descendant of the Pliocene southern mammoth of the valley of the Arno; this animal is best known from a superb specimen discovered at Durfort (Fig. 42) and preserved in the Paris Museum. It is said to have attained a height of over 12 feet as compared with 11 feet 3 inches, the height of the largest existing African elephants. It is probable that all these south Asiatic migrants into Europe were partially or wholly covered with hair, in adaptation to the warm, temperate climate of the summers and the cool winters. To the south, in the still milder climate of Italy, the arrival of another great species, known as the 'ancient' or 'straight-tusked elephant' (E. antiquus), is recorded. This animal had not yet reached France or Britain.

Preying upon the defenseless members of this heterogeneous fauna were the great machærodonts, or sabre-tooth tigers, which ranged over Europe and northern Africa and into Asia. It does not appear that the true lions (Felis leo) had as yet entered Europe.

An intercommunication of life over a vast area extending 6,000 miles from the Thames valley on the west to India on the southeast is indicated by the presence of six or more similar or related species of elephants and rhinoceroses. Twenty-five hundred miles southeast of the foot-hills of the Himalayas similar herds of mammals, but in an earlier stage of evolution, roamed over the island of Java, which was then a part of the Asiatic mainland.

The Trinil Race of Java

The human interest in this great life throng lies in the fact that the migration routes opened by these great races of animals may also have afforded a pathway for the earliest races of men. Thus the discovery of the Trinil race in central Java, amidst a fauna closely related to that of the foot-hills of the Himalayas and more remotely related to that of southern Europe, has a more direct bearing upon our subject than would at first appear.

On the Bengawan River in central Java, a Dutch army surgeon, Eugen Dubois, had been excavating for fossils in the hope of finding prehuman remains. In the year 1891 he found near Trinil a deposit of numerous mammal bones, including a single upper molar tooth which he regarded as that of a new species of ape. On carefully clearing away the rock the top of a skull appeared at about a meter's distance from the tooth. Further excavation at the close of the rainy season brought to light a second molar tooth and a left thigh-bone about 15 meters from the spot where the skull was found, imbedded and fossilized in the same manner. These scattered parts were described by Dubois(13) in 1894 as the type of Pithecanthropus erectus,[O] a term signifying the upright-standing ape-man. The specific term erectus refers to the thigh-bone, of which the author observes: "We must therefore conclude that the femur of Pithecanthropus was designed for the same mechanical functions as that of man. The two articulations and the mechanical axis correspond so exactly to the same parts in man that the law of perfect harmony between the form and function of a bone will necessitate the conclusion that this fossil creature had the same upright posture as man and likewise walked on two legs.... From this it necessarily follows that the creature had the free use of the upper extremities—now superfluous for walking—and that these last were no doubt already far advanced in that line of differentiation which developed them in mankind into tools and organs of touch.... From a study of the femur and skull it follows with certainty that this fossil cannot be classified as simian.... And, as with the skull, so also with the femur, the differences that separate Pithecanthropus from man are less than those distinguishing it from the highest anthropoid.... Although far advanced in the course of differentiation, this Pleistocene form had not yet attained to the human type. Pithecanthropus erectus is the transition form between man and the anthropoids which the laws of evolution teach us must have existed. He is the ancestor of man."

Thus the author placed Pithecanthropus in a new family, of the order Primates, which he named the Pithecanthropidæ.

Fig. 31. Geological section of the volcano of Lawoe in the Solo River basin.
Drawn by C. A. Reeds.

The geologic age of the bones referred to is a matter of first importance. The remains of Pithecanthropus lay in a deposit about one meter in thickness, consisting of loose, coarse, tufaceous sandstones, below this a stratum of hard, blue-gray clay, and under that marine breccia. Above the Pithecanthropus layer were the 'Kendeng' strata, a many-layered tufaceous sandstone, about 15 meters in thickness. This geologic series was considered by Dubois and others to be of late Tertiary or Pliocene age; Pithecanthropus accordingly became known as the long-awaited 'Pliocene ape-man.' Subsequent researches by expert geologists have tended to refer the age to the early Pleistocene.(17) According to Elbert(18) the Kendeng strata overlying the Pithecanthropus layer correspond to an early pluvial period of low temperature and, in point of time, to the Ice Age of Europe. For even in Java one can distinguish three divisions of the Pleistocene period, including the first period of low temperature to which the Pithecanthropus layer is referred.

The fossil mammals contained in the Pithecanthropus layer have also been thoroughly studied,(19) and they tend to confirm the original reference to the uppermost Pliocene. They yield a very rich fauna similar to that of the Siwalik hills of India, including the porcupine, pangolin, several felines, the hyæna, and the otter. Among the primates beside Pithecanthropus there is a macaque. Among the larger ungulates are two species of rhinoceros related to existing Indian forms, the tapir, the boar, the hippopotamus, the axis and rusa deer, the Indian buffalo, and wild cattle. It is noteworthy that three species of late Pliocene elephants, all known as Stegodon, and especially the species Stegodon ganeza, occur, as well as Elephas hysudricus, a species related to E. antiquus, or the straight-tusked elephant, which entered Europe in early Pleistocene times. Fossils of the same animals are found in the foot-hills of the Himalayas of India, about 2,500 miles distant to the northwest. The India deposits are considered of uppermost Pliocene age,(20) for this is the closing life period of the upper Siwaliks of India.

Certainly Java was then a part of the Asiatic continent, and similar herds of great mammals roamed freely over the plains from the foot-hills of the Himalaya Mountains to the borders of the ancient Trinil River, while similar apes inhabited the forests. At this time the orang may have entered the forests of Borneo, which are at present its home; it is the only ape thus far found in the uppermost Pliocene of India. We may, therefore, anticipate the discovery, at any time, in India of a race similar to Pithecanthropus.

The geologic age of the Trinil race is, therefore, to be considered as late Pliocene or early Pleistocene.

This great discovery of Dubois aroused wide-spread and heated discussion, in which the foremost anatomists and palæontologists of the world took part. Some regarded the skull as that of a giant gibbon, others as prehuman, and still others as a transition form. We may form our own opinion, however, from a fuller understanding of the specimens themselves, always keeping in mind that it is a question whether the femur and the skull belong to the same individual or even to the same race. First, we are struck by the marked resemblance which the top of the skull bears, both on viewing it from the side and from above, to that of the Neanderthal race. This fully justifies the opinion of the anatomist Schwalbe(21) that the skull of Pithecanthropus is nearer to that of Neanderthal man than to that of even the highest of the anthropoid apes. As measured by Schwalbe, the index of the height of the cranium (Kalottenhöheindex) may be compared with others as follows:

This accords with the estimate of the brain capacity[P] of 855 c.cm. (Dubois) as compared with 1,230 c.cm., the smallest brain capacity found in a member of the Neanderthal race. Second, as seen from above, we are struck with the great length of the calvarium as compared with its breadth, the cephalic index or ratio of breadth to length being 73.4 per cent (Schwalbe) as compared with 73.9 per cent in the Neanderthal type skull; this dolichocephaly accords with the fact that all of the earliest human races thus far found are long-headed, although according to Schwalbe(22) all anthropoids are broad-headed. This is a very important distinction. The third feature is the prominence and width of the bony eyebrow ridges above the orbits, which are almost as great as in the chimpanzee and greatly exceed those of the Neanderthal race and of the modern Australian. The profile of the Trinil head restored by McGregor (Fig. 38) exhibits this prominent bony ridge and the low, retreating forehead. In the latest opinion of Schwalbe(23) Pithecanthropus may be regarded as one of the direct ancestors of Neanderthal man and even of the highest human species, Homo sapiens. He also considers that when the lower jaw of the Trinil race becomes known, it will be found to be very similar to that of the Heidelberg man, the final conclusion being that Pithecanthropus and the nearly allied Heidelberg man may be regarded as the common ancestors of the Neanderthal race, on the one hand, and of the higher races on the other. There are, however, reasons for excluding Pithecanthropus from the direct ancestral line of the higher races of man.

This prehuman stage has, none the less, a very great significance in the developmental history of man. In our opinion it is the very stage which, theoretically, we should anticipate finding in the dawn of the Pleistocene. A similar view is taken by Büchner,(24) who presents in an admirable diagram (Fig. 117) the result of his comparison of twelve different characters in the skulls of Pithecanthropus, the Neanderthals, the Australians, and the Tasmanians. One of the main objects of Büchner's research was a very detailed comparison of the Trinil skull with that of the lowly and now extinct Tasmanian race, which, we observe in the diagram, occupies a position only a little higher than that of the Spy-Neanderthal race.

If the femur belongs with the skull, the Trinils were a tall race, reaching a height of 5 feet 7 inches as compared with 5 feet 3 inches in the Neanderthals. The thigh-bone (Fig. 122) has a very slight curvature as compared with that of any of the apes or lemurs, and in this respect is more human; it is remarkably elongate (455 mm.), surpassing that of the Neanderthals; the shin-bone (tibia) was probably correspondingly short. The two upper grinding-teeth preserved are much more human than those of the gibbon, but they do not resemble those of man closely enough to positively confirm the prehuman theory. Dubois observes:(25) "That the tooth belongs to some hominid form needs no further demonstration. Aside from its size and the greater roughness of the grinding surface, it differs from the human grinder in that the less developed cusp of Pithecanthropus is the posterior cusp next the cheek, while in man it is generally the posterior cusp next the tongue. The simplification of the crown and the root of the Trinil grinder is quite as extensive as it usually is in man."

Various efforts have been made to supplement the scattered and scanty materials collected by Dubois. The Selenka expedition of 1907-8 brought back a human left lower molar as the only result of an express search for more Pithecanthropus remains. Dubois is also said to possess the fragment of a primitive-looking lower jaw from the range known as the Kendeng Hills, at the southern base of which lies the village of Trinil.

It remains for us to consider the stage of psychic evolution attained by the Trinil race, and this naturally turns upon the erect attitude and what little is known of the size and proportions of the brain.

The assumption of the erect attitude is not merely a question of learning to balance the body on the hinder extremities.(26) It involves changes in the interior of the body, the loss of the tail, the freeing of the arms, and the establishment of the diaphragm as the chief muscle of respiration. The thigh-bone of Pithecanthropus is so much like that of man as to support the theory that the erect position may have been assumed by the ancestors of man as early as Oligocene times. It would appear that Pithecanthropus had free use of the arms and it is possible that the control of the thumb and fingers had been cultivated, perhaps in the fashioning of primitive implements of wood and stone. The discovery of the use of wood as an implement and weapon probably preceded that of the use of stone.

Elliot Smith describes this stage of development as follows:(27) "... The emancipation of the hands from progression threw the whole responsibility upon the legs, which became more efficient for their purpose as supports once they lost their prehensile powers and became elongated and specialized for rapid progression. Thus the erect attitude became stereotyped and fixed and the limbs specialized, and these upright simians emerged from their ancestral forests in societies, armed with sticks and stones and with the rudiments of all the powers that eventually enabled them to conquer the world. The greater exposure to danger which these more adventurous spirits encountered once they emerged in the open, and the constant struggles these first semihuman creatures must have had in encounters with definite enemies, no less than with the forces of Nature, provided the factors which rapidly weeded out those unfitted for the new conditions and by natural selection made real men of the survivors."

The undeveloped forehead of Pithecanthropus and the diminutive frontal area of the brain indicate that the Trinil race had a limited faculty of profiting by experience and accumulated tradition, for in this prefrontal area of the brain are located the powers of attention and of control of the activities of all other parts of the brain. In the brain of the ape the sensory areas of touch, taste, and vision predominate, and these are well developed in Pithecanthropus. The central area of the brain, which is the storehouse of the memories of actions and of the feelings associated with them, is also well developed, but the prefrontal area, which is the seat of the faculty of profiting by experience or of recalling the consequences of previous responses to experience, is developed to a very limited degree.(28) Thus, while the brain of Pithecanthropus is estimated at 855-900 c.cm., as compared with 600 c.cm. of the largest simian brain, and 930 c.cm. of the smallest brain recorded in the lower members of the human race, it indicates a very low stage of intelligence.

Absence of Palæoliths and Presence of Eoliths in Western Europe

Returning to First Interglacial conditions in Europe, we observe that the river courses flowed through the same valleys as at present but that in early glacial times the channels were far broader and were elevated from 100 to 150 feet above the present relatively narrow river levels. The vast floods of the succeeding glaciation filled these valleys, but some of the 'high terraces' were already formed. It is extremely important to note that Pre-Chellean flints or true palæoliths have never been found in the sands or gravels of these 'high terraces.'

Eoliths found on this 'high-terrace' level at St. Prest belong to the Prestien culture of Rutot,(29) who regards this station as of Upper Pliocene age. These, like other supposed Eolithic flints, are very rough, but, rude as they are, they generally exhibit one part shaped as if to be grasped by the hand, while the other part is edged or pointed as for cutting. It is generally admitted that these flints are mostly of accidental shapes, and there has been little or no proof of their being fashioned by human hands. On this point Boule(30) observes: "As to the eoliths, I have combated the theory not only because it seems to me improbable but because a long geological experience has shown me that it is often impossible to distinguish stones split, cut, or retouched by purely physical agents from certain products of rudimentary workmanship."

On the other side, it is interesting at this point to quote the words of MacCurdy:(31) "My opinion, based on personal experience, ... is that the existence of a primitive industry, antedating what is commonly accepted as Palæolithic, has been established. This industry occurs as far back as the Upper Miocene and continues on through the Upper Tertiary into and including the Lower Quaternary. The distinguishing characters of the industry remain but little changed throughout the entire period, the subdivision of the period into epochs being based on stratigraphy [geologic stages] and not on industrial characters. The requirements in the way of tools being very simple and the supply of material in the way of natural flakes and fragments of flint being very plentiful, the inventive powers of the population remained dormant for ages. Hammer and knife were the original tools. Both were picked up ready-made. A sharp-edged, natural flake served for one, and a nodule or fragment served for the other. When the edge of the flake became dulled by use, the piece was either thrown away or the edge was retouched for further use. If hammer or flake did not admit of being held comfortably in the hand, the troublesome points or edges were removed or reduced by chipping. The stock of tools increased slowly with the slowly growing needs. As these multiplied and the natural supply of raw material diminished, the latter was supplemented by the manufacture of artificial flakes. When the lesson of associating definite forms of implements with definite uses was learned, special types arose, notably the amygdaloid implement and the poniard. Then came the transition from the Eolithic to the Palæolithic, a stage that has been so thoroughly investigated by Rutot."

It is not improbable that the Trinil race was in a stage of Eolithic culture; it is highly probable that the prehuman races of this very remote geologic age used more than one weapon of wood and stone.

The Great Second Glaciation

(Fig. 25, p. 65)

In early Pleistocene times a general elevation of southern Europe united the islands of the Mediterranean with Europe on the north and with Africa on the south, forming broad land connections between the two continents which afforded both northward and southward migration routes. At this time certain characteristically African mammals, such as the straight-tusked elephant and the lion, were probably finding their way north; Sicily at this time gained its large fauna of elephants and hippopotami, and the island of Malta was connected with the mainland, as well as the easterly islands of Cyprus and Crete. It appears probable that the connection between the Italian mainland and Malta was renewed more than once.

The approach of the second glaciation is indicated along the southeast coast of Great Britain by the subsidence of the land and the rise of the sea, accompanied by a fresh arctic current, bringing with it an invasion of arctic mollusks which were deposited in a layer of marine beds directly over those which contain the rich warm fauna and flora of the 'Forest Bed of Cromer,' Norfolk.(32) It also appears probable that a cold northern current swept along the western coasts of Europe, and Geikie estimates that a lowering of temperature occurred of not less than 20° Fahr., a change as great as is now experienced in passing from the south of England to the North Cape.