10G 
GEOGRAPHICAL DESCRIPTION OP THE ROCKY MOUNTAINS REGION. 
The general character of the Hell Gate river, its valley, and the adjacent mountain slopes, has 
been stated. Two routes leading from this river to Fort Benton were examined by Lieutenant 
Mullan in the month of March, 1S54: one along the Little Blackfoot and its south fork, across 
the mountains to the Missouri, and thence along the bluffs or the banks of that river to Fort Ben¬ 
ton; and the other leading up the north fork of the Little Blackfoot and to Fort Benton, north 
of the Missouri, and on the prairies between that stream and the route pursued by the main party 
of the exploration in September, 1853. At the forks of the Little Blackfoot, Lieutenant Mullan 
found the snow in March ten inches deep. The bluffs on the banks of the Missouri, alluded to 
above, may be considered as extending from a point thirty miles above the falls to near the three 
forks of that river. They may be described as formidable mountain spurs, extending along the 
Missouri for about one hundred and fifty miles, and being fifteen miles wide, the principal form¬ 
ations consisting of granite, the growth being an abundance of the large species of pine; and 
these characteristics, together with the fact that it was exceedingly difficult for a pack train to pass 
through these spurs, indicated that here a route from east to west, either for a rail or wagon 
road, must be sought at a greater distance from the Missouri. This river flows through these spurs 
in what is called by Lewis and Clark the “Gate of the Mountains.” It has here a rapid current, 
and is, in places, very deep and narrow. Lieutenant Mullan arrived at Fort Benton on the morn¬ 
ing of the 14th, and started on his return to the Bitter Root valley on that of the 17th of March, 
carrying with him a wagon drawn by four mules. Fie arrived at the St. Mary’s village on the 
30th of March. The principal facts of the geography of the country which were developed by 
Lieutenant Mullan during this tour are as fallows: First, as to the climate, he crossed those 
mountains at a time when it has been hitherto thought impracticable to travel; found, in the begin¬ 
ning of March, ten inches of snow at the forks of the Little Blackfoot; no snow east of the mount¬ 
ains ; and on his return, in the latter part of March, found no snow at all on the route; and he had 
good grass throughout the journey for his animals. Second, as to the facility of communication, 
he found plenty of wood and water, but an indifferent route even for a pack-train in going to 
Fort Benton, and in returning he passed over a country which was favorable for a wagon road, 
and which presented a very fine approach to the mountains for a railroad ; and the divide, where 
he crossed it, being a low ridge, with an almost imperceptible ascent and descent. All these 
facts will give this one a favorable place, when considered in competition for a railroad route 
with the others examined. 
For detailed information in regard to the general character of the mountain region, I will refer 
you to the sub-reports of Lieutenant Mullan, G No. 23, G No. 24, G No. 25; of Lieutenant 
Donelson, F No. 18; of Mr. Tinkham, F No. 19; of Dr. John Evans, F No. 20. 
