LINE OF THE MARIAS PASS. 
279 
An interval of only about thirty-three miles lies between the broken, volcanic country resting 
on the Missouri and the summit of the pass by which I crossed the Rocky Mountain divide, 
entering the valley of a fork of Hell Gate river—termed by Lieutenant Mullan Little Blackfoot 
river. We were little troubled either with snow or cold after getting within forty miles of the 
summit of the mountains, the thermometer never ranging lower than 20° above zero, and generally 
much higher. The exact configuration of the pass I have given in my general railroad report. On 
the 10th of November I passed over, in company with a large troop of Pend d’Oreille Indians 
returning from the buffalo hunt. The ridge which constitutes the divide is a mere hill, up which, 
on the eastern side, loaded wagons can be drawn without serious difficulty; and the descent on 
the western slope is very gradual, and, for a wagon-road, all that is desirable. An inch or two of 
snow lay on the ground on the eastern side of the hill, and what little was on the summit was 
whirled into small heaps and drifts. 
Following down the valley to its junction with Blackfoot river, as I estimated, about ninety- 
five miles from the summit, (much too small an estimate, according to Lieutenant Mullan’s 
odometer measurement,) the valley is unusually favorable either for a wagon route or a railway. 
From the running water at the foot of the divide to Hell Gate, the valley, according to my 
estimated distances, has an average descent of twenty-two and a half feet per mile, (undoubtedly 
greater than the actual fall by several feet per mile,) is generally wider than Blackfoot River 
valley, is generally unobstructed by the woods; and, although the present trail in several 
instances for a few miles is steep and difficult when forced to the hill-side by'the river, all these 
difficulties could be removed with a small amount of labor, or apparently avoided without 
labor sometimes, by taking the bed of the river for a short distance, (the river has a general 
depth of near three feet,) or by making river crossings. 
The greater portion of this valley is a desirable region for settlement. The soil is often 
gravelly, as is the soil in St. Mary’s valley, but it is fertile, and there are many agreeable and 
promising locations for farming, where a good soil, plenty of good wood sufficiently near for 
lumbering or fuel, pure cool water, good grazing, an agreeable and healthy climate, and a 
pleasing prospect, are inducements not often found united, and are sufficiently attractive to 
throng these mountain valleys at no distant day with a central population of vast importance, 
making in the heart of the mountains, and midway between the Missouri and Columbia, a central 
depot of supplies, a distributing point of labor and materials, and finally a region productive of 
valuable exports. I do not think there will be any essential increase of distance over the route 
by way of Blackfoot river from Fort Benton to St. Mary’s. 
I reached Hell Gate, near the river of Hell Gate, and Blackfoot river, on the 15th of Novem¬ 
ber. In descending the valley the weather was generally mild, but still colder than what we 
experienced for nearly a month following. The mercury in one case descended as low as 12° 
above zero, but this was an exceptional case. We had several short squalls of damp snow, 
lodging for only a short time on the ground, and some little rain. 
Turning up the St. Mary’s valley, on November 17th I rested at Lieutenant Mullan’s winter 
establishment, in St. Mary’s valley, fourteen miles above Fort Owen; the weather mild and 
pleasant, and, during my stay there, occasionally rainy ; the grass good, and the animals of the 
expedition, with the multitude of horses and cattle owned by the Indians and half-breeds, in 
the most thriving condition. 
On November 20th, with a fresh band of animals, and renewed outfit of provision, &c., I was 
in camp, halting on the Sabbath, some nine or ten miles from Lieutenant Mullan, up the valley 
of St. Mary’s river—a mild moist day, raining gently most of the day, with a temperature rising 
to near 50° above zero. About twenty-six miles from Lieutenant Mullan’s winter post, and 
some sixty miles above Hell Gate, the St. Mary’s forks to the southeast and southwest. Here 
we left the fine open valley characterizing the St. Mary’s river, and tracing up the western 
fork, the wooded hills immediately closed in upon the stream ; the valley narrowed until it was 
