scientific explorers.
The first attempt to reach the region of the Yellowstone was
made in 1856, but failed, and it was not until 1869 that an
exploring party entered this marvellous valley. A second party
reached the Yellowstone region in 1870, and Mr. N. P. Langford
wrote a glowing account of the wonders observed. The first
detailed description of the locality was made by Dr. Hayden,
chief of the Geological Survey of the Territories, in 1871.
From this extended and highly interesting account we can only
quote a few passages, selecting those which relate to the hot
springs and geysers of the wonderful Fire-Hole River region.]

Early in the morning of August 30 the valley was literally filled with
columns of steam, ascending from more than a thousand vents. I can
compare the view to nothing but that of some manufacturing city like
Pittsburg, as seen from a high point, except that instead of the black
coal smoke there are here the white delicate clouds of steam. Small
groups or solitary springs that are scattered everywhere in the woods
upon the mountain-sides, and which would otherwise have escaped
observation, are detected by the columns of steam. It is evident that
some of these groups of springs have changed their base of operations
within a comparatively recent period; for about midway on the east side
of the lower basin there is a large area covered with a thick,
apparently modern, deposit of the silica, as white as snow, while
standing quite thickly all around are the dead pines, which appear to
have been destroyed by the excessive overflow of the water and the
increased deposition. These dry trees have a most desolate look; many of
them have fallen down and are incrusted with the silica, while portions
that have fallen into the boiling springs have been reduced to a pulp.

This seems to be one of the conditions of silicification, for when these
pulpy masses of wood are permitted to dry by the cessation of the
springs, the most perfect specimens of petrified wood are the result. In
one instance a green pine-tree had fallen so as to immerse its thick top
in a large hot basin, and leaves, twigs, and cones had become completely
incrusted with the white silica, and a portion had entered into the
cellular structure, so that when removed from the water and dried in the
sun, very fair specimens were obtained. Members of my party obtained
specimens of pine-cones that w