as it is pushed upward, represents the log; the river, which is
stationary, represents the saw.

One might look a long way to find the wealth created by this muddy
torrent. But the wealth is there, though it is certainly a long way from
the canyon; moreover, the rock waste itself is the wealth, and great
wealth it is. The water of the river is very muddy. Dip up a bucket
filled to the brim and allow it to stand for ten or twelve hours. There
is an inch or two of clear water at the top, while at the bottom there
is a thick, muddy paste of sand, clay, and red earth. All this rock
waste the current is sweeping along to the Gulf of California.

Every overflow along the banks of its lower course spreads this rich,
nutritious rock waste over the flood plain. Imperial Valley is filled
with it; and this, together with the flood plain above and below,
constitutes an area of productive land about as large as the State of
Illinois. Moreover, the area is constantly increasing, because of the
enormous amount of rock waste which the river daily bears to the Gulf
of California. In time, a long time as years are measured, the gulf will
be entirely filled--and what a valley of prairie land there will be.

CHAPTER III

YELLOWSTONE PARK

In the northwestern part of Wyoming, at the summit of the continent, is
a tract of land containing more than three thousand square miles. It is
a region which attracts thousands of sightseers every year; yet
inconceivable as it may now seem, this marvellous region was unknown to
the world until 1870. Being difficult of access, because flanked by high
mountains on all sides, and possessing no mineral deposits of value,
there was but little inducement for any one but a hunter or a trapper to
penetrate it.

John Coulter, a frontiersman, was probably the first white man to set
foot within its territory. He was a member of the Lewis and Clark
Expedition and, having observed that there were many beavers in the
headwaters of the Missouri River, desired to try trapping there. Having
obtained permission to leave the expedition before its return to St.
Louis, he forthwith set out to hunt and trap in that region. This was in
1807.

While following his favorite employment he met with many strange and
exciting adventures with both Indians and wild beasts. And during his
wanderings he beheld sights so marvellous as to tax the credulity of
even his own senses; among them a glass mountain, geysers sendin