ounds. They are the old hunting and
fishing villages. They are of different sizes; some are a quarter of a
mile long and half as wide. They are built up of things that the
hunters and fishermen threw away: oyster and mussel and periwinkle
shells; bones of the wolf, the hyena, the dog; of wild duck, swan, and
grouse; of cod, herring, flounder, and other deep-sea fish. Many of
the bones had been split open for the purpose of extracting the marrow.
Besides bones, there are also pieces of burnt wood; and there is sea
plant, which may have given salt.

[Illustration: A bone awl; found in a cave in England]

The stone tools and weapons found in the heaps are axes, knives,
hammers, awls, lance heads, and sling stones--all of rude make. There
are also bits of rude pottery, which show that these men knew a little
more than the cave men; they knew how to bake clay. They were ahead of
the cave men also in having one tamed animal--the dog. No bones were
found of any tamed animal except the dog, and this seems to show that
it was the earliest animal tamed by man.

Mounds like those in Denmark are found in many other countries: in our
own land where the red men lived; in Africa, the land of the black man;
and in Asia, where the brown man lives. Wherever man has led a
wandering life, eating fish and leaving their bones behind him, these
heaps are found; and they are always by the sea or by a river.

CHAPTER XVII

HOW THE EARTH LOOKED WHEN THE SHELL MEN AND THE CAVE MEN LIVED

At the time when the cave men and the shell men lived, the earth looked
much as it looks now, as far as hills and rivers and trees and grass
could make it. The earth had its seasons--its spring and summer, its
autumn and winter. Then, as now, the forests dropped their leaves in
autumn. Many leaves of oak, maple, poplar, and hickory fell upon
clayey soil and left their imprints; and the clay afterwards turned to
stone, and the imprints show us that the forests of the cave men were
like our own.

The insects, too, were the same as those of our own fields. We know
this because the gum flowed down the pine trees then as now; and ants,
crickets, butterflies, grasshoppers, and spiders visiting the tree were
held and covered. The gum turned to stone and made the amber of a
later time and kept the insects within it unchanged, and there within
the amber we see the insects that the cave men knew.

The animals, also, were much the same as those o