s
belong in this grouping. Four national parks of to-day were then in the
making, Mount Rainier in Washington, Crater Lake in Oregon, Lassen
Volcanic in California, and the Yellowstone in Wyoming. Subterranean
heat, remaining from those days of volcanic activity, to-day boils the
water which the geysers hurl in air.

In the northeastern part of the Yellowstone a large central crater was
surrounded by smaller volcanoes. You can easily trace the conformation
from Mount Washburn which stood upon its southeastern rim, heaped there,
doubtless, by some explosion of more than common violence. This volcanic
period was of long duration, perhaps hundreds of thousands of years. In
the northeastern part of the park the erosion of a hill has exposed the
petrified remains of thirteen large forests in layers one on top of the
other, the deep intervening spaces filled with thick deposits of ashes.
Thirteen consecutive times were great forests here smothered in the
products of eruption. Thirteen times did years enough elapse between
eruptions for soil to make and forests to grow again, each perhaps of
many generations of great trees.

Yellowstone's mountains, then, are decayed volcanoes, its rock is lava,
its soil is ash and disintegrated lava. The resulting outline is soft
and waving, with a tendency to levels. There are no pinnacled heights,
no stratified, minareted walls, no precipiced cirques and
glacier-shrouded peaks. Yet glaciers visited the region. The large
granite boulder brought from afar and left near the west rim of the
Grand Canyon with thousands of feet of rhyolite and other products of
volcanism beneath it is alone sufficient proof of that.

Between the periods from volcano to glacier and from glacier to to-day,
stream erosion has performed its miracles. The volcanoes have been
rounded and flattened, the plateaus have been built up and levelled, and
the canyons of the Yellowstone, Gibbon, and Madison Rivers have been
dug. Vigorous as its landscape still remains, it has thus become the
natural playground for a multitude of people unaccustomed to the rigors
of a powerfully accented mountain country.

The fact is that, in spite of its poverty of peaks and precipices, the
Yellowstone country is one of the most varied and beautiful wildernesses
in the world. Among national parks it gains rather than loses by its
difference. While easily penetrated, it is wild in the extreme, hinting
of the prairies in its broad opens, pas