oden
huts built on piles in the shallow shores of lakes. It is an evidence
that life on land is becoming as stimulating as we find it in the age of
Deinosaurs or early mammals. These pile-villages of Switzerland lasted
until the historical period, and the numerous remains in the mud of the
lake show the gradual passage into the age of metal.

Before the metal age opened, however, there seem to have been fresh
invasions of Europe and changes of its culture. The movements of the
various early races of men are very obscure, and it would be useless
to give here even an outline of the controversy. Anthropologists have
generally taken the relative length and width of the skull as a standard
feature of a race, and distinguished long-headed (dolichocephalic),
short-headed (brachycephalic), and middle-headed (mesaticephalic) races.
Even on this test the most divergent conclusions were reached in regard
to early races, and now the test itself is seriously disputed. Some
authorities believe that there is no unchanging type of skull in a
particular race, but that, for instance, a long-headed race may become
short-headed by going to live in an elevated region.

It may be said, in a few words, that it is generally believed that two
races invaded Europe and displaced the first Neolithic race. The race
which chiefly settled in the Swiss region is generally believed to have
come from Asia, and advanced across Europe by way of the valley of the
Danube. The native home of the wheat and barley and millet, which, as
we know, the lake-dwellers cultivated, is said to be Asia. On the other
hand, the Neolithic men who have left stone monuments on our soil are
said to be a different race, coming, by way of North Africa, from Asia,
and advancing along the west of Europe to Scandinavia. A map of the
earth, on which the distribution of these stone monuments--all probably
connected with the burial of the dead--is indicated, suggests such a
line of advance from India, with a slighter branch eastward. But the
whole question of these invasions is disputed, and there are many who
regard the various branches of the population of Europe as sections of
one race which spread upward from the shores of the Mediterranean.

It is clear at least that there were great movements of population, much
mingling of types and commercial interchange of products, so that we
have the constant conditions of advance. A last invasion seems to have
taken place some two or th