STONE AGE, the name given to that pe riod in the development of prehistoric man kind when stone, bone, shells and wood were the only materials employed as tools, weapons, and implements. The term first came into recognized use by the publication in 1865 of (Prehistoric Times,' written by Sir John Lubbock (Lord Avebury), who compiled and set in order the discoveries made in France and elsewhere during the previous half century. He classified the prehistoric period into three divisions, namely: Iron Age, when bronze, copper and stone were superseded by iron in most instruments and weapons, continuing to the present; Bronze Age, preceding the use of iron, when bronze was the predominant material; and Stone Age, still earlier, in whith, until near its close, no metal was made use of by men.
The Stone Age was further divided by Lubbock into I. Paleolithic, Old Stone Age, the more ancient time of chipped stone im plements; and 2. Neolithic, New Stone Age, the more recent time of polished stone im plements. This classification persists, but further collection of materials has enabled archaeologists to define several subdivisions, especially in the Paleolithic part, marking successive changes in the population and ad vances in culture, at least in southern and western Europe. Elsewhere there seems never to have been such a concentration of primitive humanity nor have its remains been so thoroughly studied; nevertheless it is possible in a general way to arrange the facts gathered in all parts of the world into the European culture-scheme. Chronologically, however, this cannot be done. Some peoples learned how to smelt and forge iron long before others; bronze was made and cast in some countries earlier than in others; and meanwhile races and tribes elsewhere continued in ignorance of either. In fact, savage peoples in remote corners of the world remain in the Stone Age to the present time, and will continue to do so indefinitely, except for such improvements as they may adopt from more enlightened neighbors. The succession of stages in cultural evolution to be outlined in this article never theless accords with the truth as applied to any one region or race, because there, is never a retrogression from a higher to a lower stage. At the same time it seems probable that the significant advances were not often, if ever, by slow evolution, but rather were owing to the conquest and occupation of each country by strangers bringing some superior degree of culture.
Paleolithic or Old Stone It is hardly a century since the chance finding of an arrowhead unmistakably of human work manship (i.e. an artifact) deep in the gravel of the Somme Valley, in France, led to an immediate and lively interest in the new science of prehistoric anthropology, and to extended explorations not only in France but all over the world. This soon resulted in large col lections of objects picked up on the surface, taken from various depths in river-sands and gravel-deposits, or found in caves, peat-bogs, graves, etc. These were attentively studied not only with reference to material, form and possible purpose, but in the light of geography and geology, in order to determine their rel ative age. The determination of the geological position in which each relic was found was particularly important. The general result of 50 years of study has been the perception and arrangement of the following series of culture groups, or °stages'', within the Paleolithic period, numbered from the oldest (1) to the most recent (8) : S. Asilian-Tardertoidan 4. Mousterian 7. Magdelenian 3. Acheulian 6. Solutrean 2. Chellean S. Aurignacian 1. Prechellean A brief account of the geological record is here necessary in order to place the earliest traces of man in the Stone Age in proper perspective. All readers are probably intermittent with the fact that an era of ntermittent glaciation that in its maximum effects covered nearly all of the northern hemisphere with an arctic climate and thick ice, intervened between the close of the Tertiary (Pleistocene division) and the beginning of the Quaternary era, which latter immediately preceded the present conditions. This Glacial Period, as it is termed, is now known to have been not continuous, but to have had any rate in Europe—three breaks, during which intervals the ice disap peared and a mild climate prevailed. This amelioration was most marked following the second ice-period, when for an immensely long time both Europe and North America were restored to a climate and appearance not greatly different from the present. Forests and vegetation were much the same as now, and most of the animals, with the addition (perhaps implying a somewhat warmer climate) of hippopotami, elephants, rhinoceroses, lions, and some other now tropical species, all long ago extinct.