No bones of the reindeer nor of the great extinct mammals are found with the polished implements, and nothing made of metals; arrow heads and rough chisels would continue to be made in this, and even in the next and the present ages, while the metals were rare and costly. The Danish shell mounds are the refuse heaps of the people around their dwellings or temporary stopping places; they contain no remains of reindeer, but bones of the domestic animals, and all kinds of household objects lost or broken, including rude pottery made by hand. Similar shell heaps have been found in the United States, especially along the seacoast, marking the former dwelling places of the aborigines of this continent; several of these have been described by Prof. J. Wyman in vols. i. and ii. of the "American Naturalist" (18G8). They are found from Maine to Florida, and are made up of the shells of the mollusks used by them as food, especially the clam and quahog, with bones of the elk, deer, beaver, bear, dog, various fur-bearing mammals, birds, and especially the great auk, now believed to be extinct; occasional pieces of charcoal, and implements of bone and stone, but no human remains, are found.

The growth upon them of large trees proves that they must be several centuries old, though not so ancient as the shell heaps of Denmark; they show a great variety of animal food, to say nothing of the vegetable; they afford no trace of any intercourse with European nations. The layers are from 4- to 3 feet thick, and sometimes 250 feet long and 40 or 50 wide, and near the seashore, which has evidently been raised since their deposition; there are sometimes several layers, separated by earth, indicating successive occupations. Some of the lake dwellings of Switzerland (see Lake Dwellings) belong to this age, while those yielding metal implements belong to the' next or bronze acre. There are evidently two classes of these lake dwellings. Many burial mounds contain flint daggers and stone implements, and none of metal. Bodies in the stone age were either buried in the sitting posture or were burned; they were rarely, if ever, extended at length. Bones of the dog in the shell heaps, and of the ox, sheep, goat, and pig in the lake villages, lead to the belief that these animals were then domesticated; the domestic fowl and the cat were unknown.

The hunting had by this time given place to the agricultural state, as we find corn-crushers, blackened wheat, barley, and flax in the lake dwellings, but no oats, rye, nor hemp; tissues of woven flax are met with. Even at this early period two kinds of skulls are found, one long and the other round, indicating the existence of at last two human races, the first perhaps belonging to men of the stone age, and the last to the bronze period, which was now coming on. In the villages of the Swiss lakes the houses were built on wooden platforms extending over the water, resting on piles driven into the mud. Similar villages have been found in Italy, Savoy, the French Jura, Germany, Scotland, and Wales; and from their number and size they must have been the centres of a numerous population, a single one having had more than 40,000 piles. Some of the people on the coast of Borneo and in parts of Polynesia make their huts on similar platforms at the present day. The charred posts and grains indicate that these villages were destroyed by fire. - In the succeeding or bronze age, implements and arms of this alloy were extensively used, and many are preserved in collections; stone implements and arrow heads are found with the bronze, showing that the former ser-viceable material was still used.

The later Swiss villages and many tumuli or mounds belong to this period. Bones of the domestic animals and cultivated plants are found instead of wild ones; the piles of the villages are cut squarely with metal, and not irregularly by stone or charred by fire; the pottery shows marks of the wheel; gold, amber, and glass were used for ornamental purposes, though silver, lead, zinc, and iron appear to have been unknown; there were no coins in use, and there are no signs of writing or inscriptions; skins were worn, though tissues of flax and wool were also used; the ornamentation is geometrical, consisting of lines, circles, zigzags, and triangles, much as is now seen on the mats made by the tribes of central Africa; the handles of the arms and bracelets indicate a small race. The use of bronze proves commerce, and the tin must have been brought from Cornwall, and copper must have been used before bronze. As copper implements are not found in western Europe, it is probable that the knowledge of bronze was introduced into and not discovered in Europe; it could not have been introduced from Italy, as the Romans never entered Denmark, and such implements have rarely been found in Italy, and none of the peculiar leaf-shaped bronze swords, so common now in the north, are seen in southern museums.

If such are of Phoenician origin, as Prof. Nilsson maintains, it must have been before their historic period, as they were familiar with iron from the earliest known times. - After a transition period, during which bronze was used with iron, as proved by iron instruments with bronze handles, though never the reverse, we come to the iron age, which leads directly to the historic. In this the weapons and cutting instruments were generally made of iron; such were in use by the Britons at the time of the Roman invasion; coins were employed, and silver was used for ornamentation of the person and of implements; the pottery was much better, and the weapons were more artistically made and ornamented. Neither bronze nor stone weapons were used in northern Europe at the beginning of our era, and the people of the north and west were considerably above the savage state. The resemblance of the rude implements in the old and in the new world, in the same stage of civilization, is very striking. - M. Lartet makes only two prehistoric ages, the stone and the metal. The stone age he divides into - 1, that of the extinct mammals, like the mammeth and the cave bear; 2, that of the migrated existing animals, the reindeer epoch; 3, that of the domesticated existing animals, the polished-stone age.

The metal age he subdivides into the bronze and the iron ages. According to him, primitive man lived in a comparatively cold, barren, and wet earth, presenting no fruits for his sustenance, and no opportunity for agried-ture; essentially predaceous and carnivorous, an eater of raw flesh, and a cannibal, like many savage races of the present day; with small skull and brain, retreating forehead and prominent jaws, short but robust, below even the New Zealander and Australian of to-day; and paying a great and superstitious respect to the dead. In the reindeer period there was an advance, as shown by the more symmetrical though unpolished weapons, but as yet no agriculture; the great mammals began to disappear, and to be replaced by smaller and more useful forms. The mastodon was evidently known to the founders of the Central American cities, and its figure is pictured on their walls; as the mastodon survived the mammoth, the former came down almost to the historic period. During the reindeer epoch the glaciers again advanced, and the climate became cold, though to a less degree and for a shorter time than before; after this came another warmer period, when the glaciers melted, causing the floods which as deluges enter into the traditions of so many nations; then the great mammals were exterminated, and the reindeer and the arctic animals retreated to the north, where they have since remained.

In the next epoch, with a continued mild climate, man became agricultural, had polished implements, and made the dog his companion. In the bronze age man made still greater advances, domesticating animals, cultivating grains and fruits, and smelting metals, especially copper. The iron age insensibly merges into the historic period. The mound-builders M. Lartet considers intermediate in civilization between the polished-stone and the bronze epochs of Europe, not in time, but in stage of advancement; they lived in towns, and were not only hunters, but miners, potters, weavers, agricultural, artistic, and commercial. The stone, bronze, and iron ages do not indicate definite periods of time in man's civilization; every race goes through these ages, some more rapidly than others. Some eastern nations had probably passed out of their stone age at least 3,000 years B. C.; some in northern and central Europe were in this age when CAesar subjugated Gaul; the Sandwich islanders were in their stone age in the time of Capt. Cook; the Esquimaux and the North American Indians generally are now in their stone age; it is simply the age of the infancy of the race.

In America the copper preceded the bronze age; the latter existed when the Spaniards first visited Mexico and Peru. The mound-builders of the Mississippi valley used implements of pure copper, hammered cold, obtained from the region of Lake Superior; they preceded the Aztecs. Judging from the forests overlying this old civilization, the copper age must have been at least 1,000 years ago. Africa had no bronze age, passing from the stone to the iron age, on account of the exceptional occurrence of iron there, which the natives work skilfully both cold and hot. The men of the iron age in ! Europe were probably the Celts, conquered and described by the Romans. The Esqui- , maux, the Australian, and the North Ameri- can Indian will probably never pass beyond the stone age, and will finally become extinct, the first from climate, and the last two from contact with superior races with which they cannot compete. It is most likely that the savage Ligurians and Iberians described by CAesar as living in caves, and conquered by him, were the southern representatives of the old stone age, while the Finns and Lapps are the more modern and northern remains of the later stone age.

The American Indians, the shepherds of Tartary, and the African races have no written history of their own; this has been attained only in comparatively recent times even by the civilized nations of Europe. From geographical causes the Tartars have always been migrating shepherds, occasionally uniting in formidable hosts, the scourges of more civilized races, as when eastern Europe was overrun by the hordes of Genghis Khan and Tamerlane. - For full information on the subject of archaeology, the reader is referred to the writings of Christy, Lartet, Boucher de Perthes, and Quatrefages in France; Schaff-hausen, Virchow, and Lindenschmit in Germany; Thomsen, Engelhardt, Steenstrup, and Nilsson in Denmark; Troyon, Keller, Morlot, Vogt, and Desor in Switzerland; Gastaldi, Canestrini, and Foresi in Italy; Schoolcraft, Squier, Foster, Davis, Whittlesey, and Wyman in the United States; Crawfurd, Prestwich, Boyd Dawkins, in England, and especially to Lyell's "Antiquity of Man," and Lubbock's "Prehistoric Times." For details on the stone age, see "Primitive Inhabitants of Scandinavia," by Sven Nilsson (London, 1808).