re
carried from the mountains out over the prairie by the ice and left
there when it melted.

Around most of these great boulders the buffalo used to walk from
time to time, rubbing against the rough surface of the rock to
scratch themselves, as a cow rubs itself against a post or as a
horse rolls on the ground--for the pleasant feeling that the rubbing
of the skin gives it.

As the buffalo walked around these boulders their hoofs loosened the
soil, and this loosened soil--the dust--was blown away by the
constant winds of summer. So, around most of these boulders, much of
the soil is gone, leaving a deep trench, at the bottom of which are
stones and gravel, too large to be moved by the wind.

This story explains how these rocks came to be like that:

Once Old Man was crossing a river and the stream was deep, so that
he was carried away by the current, and lost his bow and arrows and
other weapons. When he got to the shore he began to look about for
something to use in making a bow and arrows, for he was hungry and
wanted to kill some food.

He took the first wood he could find and made a bow and arrows and a
handle for his knife. When he had finished these things he started
on his way.

Presently, as he looked over a hill he saw down below him a bear
digging roots. Old Man thought he would have some fun with the bear,
and he called out aloud, "He has no tail." Then he dodged back out
of sight. The bear looked all about, but saw no one, and again began
to dig roots. Then Old Man again peeped over the hill and saw the
bear at work, and again called out, "He has no tail." This time the
bear looked up more quickly, but Old Man dodged down, and the bear
did not see him, and pretty soon went on with his digging.

Four times Old Man did this, calling the bear names, but the fourth
time the bear was on the watch and saw Old Man, and started after
him.

Old Man ran away as hard as he could, but the bear followed fast.
Presently, Old Man tried to shoot the bear with his arrows, but they
were made of bad wood and would not fly well, and if they hit the
bear, they just broke off. All his weapons failed him, and now the
bear was close to him. Just in front was a great rock, and when Old
Man came to that, he dodged behind it and ran around to the other
side, and the bear followed him. They kept running around the rock
for a long time and wore a deep trail about it, and because Old Man
could turn more quickly, he kept just