REPORT AND ESTIMATE. 339 
and for the next 500 feet from 122.6 to 38.8 in depth; then in 100 feet the cut reduces to 
31.4 in depth, and in 1,000 feet further to 20.8 feet in depth, and it runs out in 200 feet further. 
To resume the line down the Blackfoot from Cadotte’s Pass. From the summit level, at the 
entrance to the tunnel, the line continues down the valley for six and twenty-eight-thousandths 
miles, when it is joined by the line from Lewis and Clark’s Pass. Three-fourths of a mile 
before reaching this point it crosses the stream flowing from the pass. Continuing for four and 
one-fourth miles further, it crosses Lander’s Fork. A considerable bridge will be required 
here, consisting of a single arch of two hundred feet; excavations and embankments will average 
from fifteen to sixteen feet. It then continues down the valley, which has been gradually widening 
from the pass for nine miles, when it reaches what is known as the Сайоп. In this distance two 
streams are crossed, coming from the north. This distance is in the prairie known as the Belly. 
The work here will be very moderate, the excavations and embankments small. The Caiion is 
a low open valley, in no case less than one-third of a mile in width, and widening out two or three 
miles. Excavations and embankments are moderate. The country is mostly wooded. Seven 
miles from the entrance to the Cafion we come to a prairie of one thousand acres, which is over- 
flowed at high water, and against which special precautions will have to be made. Only one 
stream of any consequence is crossed, about three miles before issuing from the Сайоп. Leaving 
the Canon we come into the large prairie which has been particularly described in the 
narrative. At this point the Blackfoot will have to be crossed twice in a distance of a mile and 
a half. Тһе distance across the prairie is thirty-four and six-tenth miles, and the line can be 
laid in nearly a straight course by adapting the grade to the ground, at the expense of heavy 
excavations and embankments. In about eight and a half miles Salmon Trout creek is crossed, 
requiring a bridge and careful adjustment of the line. In ten and a half miles further another 
large stream is crossed, and in the remaining distance two or three small streams will have to 
be bridged; and seven miles before reaching the end of the prairie a cut must be made through 
a low ridge. 
We have now come to the lower сайоп of the Big Blackfoot. This сайоп is nineteen miles 
long, and is perfectly practicable. The river must be crossed frequently, not, probably, less 
than thirteen times, and, to avoid short curvatures, there must be heavy excavations, mostly in 
rock. Embankments will be moderate. There will be no difficulty in wasting earth. Осса- 
sionally sustaining walls must be resorted to. Іп the narrative reference has been made to the 
prairies opposite projecting points, and in locating the railroad line care must be taken to pass 
from prairie to prairie. 
In six miles further we come out of the valley of Hell-Gate into the general valley of the 
Bitter Root, at a place known as the Hell-Gate Ronde. Неге a trail crosses the Hell-Gate to 
Fort Owen. This point, in the estimate, has been called the crossing of Hell-Gate. i 
In this section of ninety-one and sixty-eight hundredths miles from the tunnel there will be 
onstruction of all kinds; timber for all purposes of construction inexhaustible; 
nd sand are found at convenient points. There are many 
Slate is to be found at the mouth of Salmon Trout creek, and 
ample materials for с 
ample supplies of water, gravel, a 
localities of good building stone. 
limestone, suitable for walls of all kinds, in the lower cafion. 
The whole descent in this distance is 1,735.8 feet, or an average grade of 18.94 feet to the 
mile. The several grades as shown on the profile, on the supposition of uniform grades for 
the several distances will vary from 63 feet to 3.1 feet to the mile. But it will be found 
advisable, to diminish excavations and embankments, not to use as low grades as three and 
