n. Where this has been tried the results have been very
satisfactory. The children, because they feel the responsibility, are
stimulated to their best thought. The pleasure they take in the play
leads them to a far more careful study of the book than they would
make without this stimulus. In addition to this, it leads them to be
alert in making use of various sources of knowledge.

_Lesson XXX._ Hunting peoples, because they live a hand-to-mouth life,
have either a feast or a famine. Game was so plentiful during the late
Pleistocene period that we may suppose that the Cave-men usually had
plenty of food. The time when a famine was most likely to occur was
early spring, before the grass furnished food for the herds which came
a little later. When food supplies begin to fail, the clan breaks up
into smaller groups, and, in case of great scarcity, each of these
groups subdivides so that food may be found.

The worship of the bear and other large animals can be traced back to
a very ancient period. It undoubtedly originated in the Pleistocene
period when man first stood in fear of these animals and tried to win
their favor by offering gifts.

_Lesson XXXI._ In Central France, the region from which the greater
part of the data used in this book is derived, small glaciers were to
be found in the upper portions of the mountain valleys, but they did
not extend far down the river valleys. In other places, however,
glaciers extended far down into the lowlands.

While this is not the place for a thorough study of the glacier, it is
possible for the children of primary grades to understand certain
phases of the subject. The teacher who attempts to make clear the
formation of the glacier may find the following quotation from Prof.
Shaler helpful: "When a glacial period comes upon a country, the
sheets of ice are first imposed upon the mountain tops, and then the
ice creeps down the torrent and river beds far below the snow line,
in a manner now seen in Switzerland and Norway. As long as the ice
streams follow the torrent-channels, they act in something like the
fashions of the flowing waters--to gouge out the rocks and deepen the
valleys; but as the glacial period advances and the ice sheet spreads
beyond the mountains enveloping the plains as well, when the glacier
attains the thickness of thousands of feet, it disregards the valleys
in its movements and sweeps on in majestic march across the surface of
the country. As long as