Just as archaeological time overlaps earlier historical time, but precedes it for the most part, so also geological time overlaps and precedes archaeological. The human remains so far found prove man's existence back through the Quaternary or Pleistocene Period, and probably into the Pliocene of the Tertiary. This places man's origin in the age of the giant mammals - the mastodon, the saber-tooth tiger, and the cave bear. The conflict with these must have been one of the problems of the earliest human society.

Archaeological Time In Europe

Geological Time

Races

Ages

Types of Culture Named from Locations

Quaternary

Recent Alluvial

Baltic

Iron

Hallstatt

10,000 years

Mediterranean

Alpine

Bronze

Mycenaean

Neolithic

Danish Kitchen-middens

Swiss Lake-dwellers

Pleistocene

Palaeolithic

Azilian-Tardenoisian

Postglacial

Cro-Magnon

Upper

Magdalenian

25,000 years

Solutrean

Grimaldi

Aurignacian

Glacial Stages

IV. 25,000 years

Neanderthal

Palaeolithic

Mousterian

3d Interglacial,

Lower

Acheulian

100,000 years

Piltdown

Chellean

III. 25,000 years

Pre-Chellean

2d Interglacial,

Heidelberg

200,000 years

II. 25,000 years

rst Interglacial,

Eolithic (?)

75,000 years

I. 25,000 years

Trinil (?) found in Java

Tertiary

Pliocene

- Adapted from Osborn, Men of the Old Stone Age.

The accompanying chart gives a conspectus of man's prehistoric career. To the reader who has never looked into this subject before, the array of strange names may seem formidable, especially those in the last column, although each one of them stands for a body of knowledge which is perfectly definite and established beyond question. A little study will make this chart fairly radiant with meaning. The figures for the years in the first column are the most uncertain feature, for they are only approximations at the best. Some geologists would allow only ten thousand years for the Postglacial and the Recent Alluvial together. But the succession of the various geological stages and their characteristics are settled beyond doubt.

Since, therefore, the length of man's past career on the earth must be measured in geological time, we should notice what geological time means. There are various ways of measuring it. The most definite one is based on the rate at which Niagara Falls wears back the gorge which it has formed. This cataract came into existence at the close of the glacial epoch when the ice cap had retreated sufficiently to allow the waters of Lake Erie to discharge into Lake Ontario. The gorge is now seven miles long and grows about four feet a year. This rate of growth must have been less rapid formerly because the waters of the upper lakes formerly discharged elsewhere - into the Mississippi by the Chicago and Illinois rivers, or into the St. Lawrence by Lake Nipissing and the Ottawa River. European geologists estimate from the rate at which the glaciers of the Alps are observed to form moraines. Geologists place the beginning of the Quaternary at from five hundred thousand to a million years ago, and they make the Tertiary at least three times as long as that. It is likely, therefore, that man has been on the earth for a million years; it can hardly be less than five hundred thousand, and may be much more than a million. Back of man's origin, geological time stretches away through a hundred million years more or less, during which lower forms of life were maturing and the earth was getting into the condition to make human existence possible. If we wish to let our thoughts run back of geological time, there is astronomical time, in which years become meaningless and there is no ascertainable beginning.

None of the bones which have been found show that the stature of man was ever much different from what it is now, the range of normal variation being from four to six and a half feet, but they do show a great difference in the shape of the head. The Neanderthal race had a receding chin, a receding forehead, and a brain one fifth smaller than the European of to-day. But information about this race and its still more primitive predecessors becomes more meager the farther back we go. Of peculiar interest is the Crô-Magnon race which inhabited western Europe at the beginning of the Postglacial period. This race produced the wonderful paintings and carvings on the walls of caves in France and Spain, although industrially it seems never to have advanced beyond the middle or upper stage of savagery, for there is no evidence that it made pottery, or cultivated the soil, or had domestic animals, or used the bow and arrow. The descendants of this race are still found in Dordogne in southern France. They are marked by a broad face with prominent cheek bones, and by a dolichocephalic or narrow cranium. The Crô-Magnons, according to Osborn, came from Asia, like all of the other races which have prevailed in Europe.