ss prominent in these cave men
than in those who fought the great reindeer and the mammoth farther
north.

In later times men of higher intelligence formed tribes, tamed the wild
horse, the ox, and the sheep, and made friends with the dog. Great heaps
of shells along the shores show where the tribes assembled at certain
times to feast on oysters and clams. Bones of animals used as food, and
tools, are found in these heaps, called "kitchen-middens." These are
especially numerous in Northern Europe. The stone implements used by
these tribes were smoothly polished. A higher intelligence expressed
itself also by the making of utensils out of clay. This pottery has been
found in shell heaps. So the rude cave man, who was scarcely less a wild
beast than the animals which competed with him for a living and a
shelter from storms and cold, was succeeded by a higher man who brought
the brutes into subjection by force of will and not by physical
strength.

The lake-dwellers, men of the Bronze Age, built houses on piles in the
lakes of Central Europe. About sixty years ago the water was low, and
these relics of a vanished race were first discovered. The lake bottoms
were scraped for further evidences of their life. Tools of polished
stone and of bronze were taken up in considerable numbers. Stored
grains and dried fruits of several kinds were found. Ornamental
trinkets, weapons of hunters and warriors, and agricultural tools tell
how the people lived. Their houses were probably built over the water as
a means of safety from attack of beasts or hostile men.

In our country the mound-builders have left the story of their manners
of life in the spacious, many-roomed tribal houses, built underground,
and left with a great variety of relics to the explorers of modern
times. These people worked the copper mines, and hammered and polished
lumps of pure metal into implements for many uses. With these are tools
of polished stone. Stores of corn were found in many mounds scattered in
the Mississippi Valley.

The cliff-dwellers of the mesas of Arizona and New Mexico had habits
like those of the mound-builders, and the Aztecs, a vanished race in the
Southwest, at whose wealth and high civilization the invading Spaniards
under Cortez marvelled. The plastered stone houses of the cliff-dwelling
Indians had many stories and rooms, each built to house a tribe, not
merely a family.

The Pueblo, the Moqui, and the Zuni Indians build similar dwe