These deep cuts, through which the river runs, are called canyons.  The longest of them is called the Grand Canyon (see frontispiece).  It is about two hundred miles long.  In some places it is more than a mile and a quarter deep.  The river runs at the bottom of this deep ravine.  It rushes over rapids, and plunges over falls.  Sometimes there is a little strip of rock like a shelf at the edge of the river.  In many places the walls of rock rise straight from the water, and there is no place where a man can put his feet.

Major Powell resolved to go through this canyon in boats.  No boat had ever gone down this deep, dark channel.  Two men, running away from Indians, had once gone into it on a raft.  The raft was dashed over rapids and waterfalls.  The provisions of the men were washed overboard.  One of the men was drowned, and the other at last floated out at the lower end of the canyon more dead than alive.

Being a man of science, Major Powell wanted to find out about the Grand Canyon.  He knew that it would be a fearful journey.  He and his men might all be lost, but they made up their minds to try to go through.

They did not know how long the canyon was.  They had already passed through the other canyons above, and had suffered many hardships.  They knew how wild and dangerous such places are, but whether they could ever get through this great and awful gorge they did not know.  But they got into their boats, and started down the long passage.  The sun shines down into this narrow gorge only for a short time each day.  Most of the way the walls are too steep to climb.

The boats shot swiftly down the river.  Sometimes they ran over wild rapids.  The men had many narrow escapes.  The boats bumped against the rocks, and some of the oars were broken.  New oars had to be made, and, to do this, the men had to find logs that had drifted down the river.  Sometimes Major Powell and his men had to have pitch to stop the leaks in their boats.  To get this, they had to climb up thousands of feet of rock to where some little pine trees grew.

They could not see far ahead, because the river was not straight, and the side walls of the narrow gorge shut out the view.  Sometimes they would hear a loud roaring of water ahead.  Then they knew they were coming to a waterfall.  If there was any room to walk, they would carry and drag their boat round the falls.  If there was no shelf or shore on which to carry the boats, they had to let them float down over the falls, the men on the rocks above holding ropes tied to the boats.  Sometimes they could not even do this.  Then they had to get into the boats and plunge over the falls among the rocks.  They had hard work to keep off the rocks.

More than once a boat got full of water.  The men had to let the boat run till they got to a wider place, where they could get the water out.

Their flour was spoiled by getting wet.  Their bacon became bad.  Much of their food was lost overboard.  They usually slept out on the rocks by the side of the river.  Sometimes they slept in caves.  Once they sat up all night on a shelf of rock in a pouring rain.