Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean: Vol. 1, Pt. 2

FROM BITTER ROOT VALLEY TO FORT HALL.
everything is still in and around the camp, they descend into the valley, and, in a twinkling,
stampede and-steal off evry animal, leaving the unfortunate sufferers to wend their way homeward on foot. This has been the practice of the Blackfeet for years back, and now they are the
dread and scourge of the mountains.
December 7, 1853.-Commences clear but cool, the thermometer at sunrise being at zero. Last
night also was exceedingly cool, the air being caltn and still; a short time after sunrise, however,
it moderated and became a summer-like day. This great difference in the temperature during
the night and day is somewhat remarkable; during the day the heated air seems to be confined
in the valleys of the mountains, and immediately after sunset it is replaced by a cold current
coming from the mountains, thus producing an almost instantaneous change, which at times is
exceedingly uncomfortable.
Our course during the earlier part of this day (which was 10~ east of south, magnetic) lay
over a series of low sandy ridges, covered with the artemisia, growing from three to four feet high.
This led us to a beautiful prairie valley about ten miles wide, hemmed in on all sides by high
mountains, and through which flows the southwest branch of the Jefferson fork of the Missouri.
This prairie is known by the Indians and half-breeds of the country as "Horse Prairie," a name
given it from the fact that many years ago large bands of wild horses were seen roaming over it.
Our trail crossed the branch referred to, which we found partially clogged with ice; the channel,
however, was open, being about two feet deep, with a very rapid current. Many-small gravelly
islands were to be seen in the river in the distance of two or three miles. To our right, and
about eight miles distant, were to be seen two high buttes coming within a very short distance of
each other, being on different sides of the valley, which at a distance looks like a gate in the
mountains.
Through this gate the southwestern branch of the Jeffersotn fork of the Missouri flows. Beyond
this, to the-west, the prairie, widening on each side, becomes nearly circular, but still hemmed
in by the mountains. Through the range of mountains bounding it are three gaps or passes:
the most northern tends to the Big Hole prairie; the middle one leads to the waters of the Salmon
river; the most southern one leading to the waters of the Snake river, or southern fork of Lewis
river. This middle gap is the one followed by Lewis and Clark, in their expedition to the Pacific
in 1804 and 1805, and which they found impracticable for their route to the Pacific. This southwestern fork of the Jefferson river is the one followed by Messrs. Lewis and Clark, with canoes,
during the expedition referred to. Our trail crossing this branch, or fork, led across its valley till
we struck the valley of the southwestern branch, which we found to be the larger of the two.
This branch flows through a valley about six or eight miles wide. The stream is about sixty feet
wide and two feet deep, with a rapid current, and pebbly or gravelly bed. It, like the southwestern branch, is perfectly destitute of timber, save a few cotton-wood trees, growing in clumps
of four or five, and at least twenty miles apart. The grass in both valleys is exceedingly fine,
and which at night our animals, after travelling twenty-five miles, duly appreciated.
At this junction of the mountain valleys is a high ridge of brownish colored stone, about four hundred feet high, which has been worn by the weather into every possible fantastic shape. Arch,
dome, steeple, cave, each has its place in this singular formation. Its upper portion seems to
be tenanted by the feathered tribe, while that near the base seems to be formed into numerous
caves, where the bear and wolf has each its lodging. Game to-day we saw none, save a few
large prairie-hen or heath-cock, and a few white hares with red ears; these latter being much
larger th'an the ordinary rabbit of the East. This place is generally a favorite resort for game;
but, unfortunately for us, it seemed to be most scarce when the necessity for it was the greatest.
[ should mention, however, that we did kill one prairie chicken, which at night, with a cup of
tea and hard bread, made us an ample repast. At our camp of this night we found a few cottonwood trees, which afforded us an abundance of tuel, being to us a pleasant change from the last
few nights, when our fuel consisted of wild sage bushes and willows.
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