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

ROCKY MOUNTAIN PASSES.
other side, the tributary of Marias river descends near 1,200 feet in sixteen miles. There are,
probably, passages of the mountains connecting other branches of the Marias river with other
tributaries of Flathead river, and giving, perhaps, opportunities for passing the divide with more
ease than by the way explored; and should a line in this direction be thought desirable, it should
be remembered that the field has been very partially explored. The mountains here have, however, a very different character from what they have farther south, being higher and forbidding,
their sharp, gray peaks stripped of all vegetation, in every direction towering above the mass of
wooded mountains and valleys below them.
A route through this pass can be preferable only as connecting with a route to the north of
Flathead river. To follow down the valley of Flathead river after arriving at Flathead lake,
will make it greater in length, in addition to its other disadvantages. The reconnaissance did
not show that it was impossible to proceed westwardly in a more direct line, but the only two
places in the valley containing Flathead lake and river, which were not bounded by high hills or
mountains on the western border, are at the north and south extremities of Flathead lake. These
were the only places where there appeared any possibility of breaking through the mountains.
At the south extremity of Flathead lake is a small break in the hills, running in a nearly west
direction, but this small valley has no stream of any importance in it, and there is nothing to
show that it extends farther than can be seen from thelake, a half dozen miles. Atthe upper
end of the lake the hills on the west side of the valley appear to cease for a while. There is a
prairie here of considerable extent, the eastern edge of which was followed by Mr. Tinkham, and
it may be practicable upon this prairie to proceed westwardly direct, without following Flathead river to Clark's fork. It is a matter for future examination. Of the route actually examined, Flathead river, from Jocko river to Marias Pass, and from Marias Pass to Fort Benton
across the prairie, the most difficult portion has already been noticed, the section of thirty-five
miles, including the summit. West of this, for about twenty miles the valley continues narrow,
closed in by high, precipitous, wooded mountains, and a railway here must be made with very
heavy and expensive work, rock cutting, culvert and bridge work, and sustaining masonry, with
some short curves, but without high grades. The valley then opens and closes again but once,
and then only for a very short distance, and until reaching Flathead lake the route is very
promising in its grades, curves, and the small amount of grading required; but little rock exeavation will be necessary. The western shore of Flathead lake crooks abruptly and often, following
the base of the wooded and rocky hills which border it. The construction of the road here
involves short curves, expensive rock cutting and masonry. The eastern shore appears more
promising, but has not been examined. From Flathead lake to Jocko river, following the
valley of Flathead river, the route is favorable, generally unwooded, without heavy grading or
masonry. East of the mountains a nearly straight line can be obtained from the point where the
railway line leaves Milk river to the plains near the base of the mountains, sixteen miles from
the divide. This is all dry prairie country, without wood, and with but little water on the
surface during the dry season.
The six passes next mentioned above debouche into the valley of the Bitter Root. The routes
of Lewis and Clark's Pass and Cadotte's Pass meet in the valley of the Big Blackfoot river, thirteen and a half miles west of the dividing ridge, (Cadotte's Divide.) Those by the two branches
of the Little Blackfdot meet and continue for some distance in its valley, which finally connects
with Hell Gate fork, in the valley of the Hell Gate river, and the five routes, thus becoming two,
follow down these two rivers and enter the Bitter Root valley at Hell Gate. They will be called
the Big Blackfoot, Little Blackfoot, and Hell Gate trails; each-of the twco former being easily
reached from the east by two passes over the dividing ridge, and the latter having likewise-several connexions, through the mountains, with the regions to the east.
These passes are probably all practicable for a railroad; but the pass from Wisdom river is
9ut of direction, and the Hell Gate and southern Little Blackfoot passes are approached with some
.98