206 NARRATIVE OF 1855. 
St. Regis de Borgia I found that a railroad or wagon road down that stream should take its 
right or southern bank, and thence cross the Bitter Root. The banks of the Bitter Root, on 
both sides, are exceedingly favorable to such a crossing. They are only six feet above the 
present water level on the left bank, and eight feet on the right bank. The highest water is 
five feet above the present level, and the lowest water is about three feet below; so the greatest 
rise and fall of this stream at the mouth of the St. Regis de Borgia is eight feet. The river is 
150 yards wide, which width is preserved throughout to-day's route. The regimen of the 
river is very uniform, the banks not abraded in the slightest, and, with one exception, here- 
after to be noticed, no shelving of the banks has occurred. I noticed particularly the growth 
of forest trees on the side hills throughout to-day's and every day's march on my present 
journey, and from their appearance I saw that for at least one hundred years there had not 
been a shelving on the route. The Bitter Root river, like all mountain streams, has a some- 
what sinuous course; yet the smallest curve required in a railroad line through its'valley to 
the mouth of the St. Regis de Borgia has a radius of 2,000 feet. 
It may be well to give the details of to-day's journey with some little particularity. From 
opposite the mouth of the St. Regis de Borgia, for a mile and a half the road follows a plateau 
some eight to twelve feet above the present water level; then for three-quarters of a mile it runs 
along side hills, generally low, not requiring much excavation and embankment, and with 
gentle curvatures. I observed at this point that the engineer had the choice of routes; he 
could either follow along the river bank, or lay his course somewhat inland, and it is only 
by careful location that the relative advantages of the two could be determined. Then for 
three-eighths of a mile you pass through a prairie with gentle curves; one-eighth of a mile 
side hill work again, but very slight; at the end of this distance there is a point of land 
running to the river, which must be cut through. For one mile and seven-eighths the route is 
on a plateau slightly undulating, to the extent that it is sometimes ten and again it is forty feet 
above the river level, but excavations and embankments slight. The curves are so gentle 
that for this portion of the distance the line is equivalent to a straight line. At this point 
there is a good crossing of the river, but it is not essential to make the crossing; on the 
contrary, the road should keep along the present bank. For one mile and three-quarters 
more we follow a plateau from ten to twenty feet above the water level. At the end of this 
distance are two spurs which come near to the river, affording room, however, for a road, with 
very moderate excavations and embankments. For one mile more we come on a plateau 
twenty feet above the river level, very uniform in its character and in a gentle re-entering. 
The excavations and embankments are very moderate here. For one mile further still we keep 
on the bank of the river. Hills come down near the river, but there is no rock excavation, 
and earth excavation and embankment are both moderate. For three-quarters of a mile more 
we still keep on the river bank, when we come to the only difficulty on the road. Very high, 
steep bluffs stretch along the river for 350 yards. No trees grow on the sides of the bluffs. 
It is impossible to lay along this bluff either a wagon road or a railroad by excavations of earth. 
The route must make this portion of the river by a peculiar construction hereafter to be 
described, or you must lay the course well back. From what I could see of the country I 
thought there would be no difficulty in doing so, but I cannot speak positively as to that. At 
the end of these river bluffs, that is, at 350 yards, I observed that the banks were very firmly 
fixed, both from the appearance of the grass and from here and there a tree growing. No 
change could have occurred in them for many years, probably not for a hundred years, and 
the structure to be resorted to is the following : There will be no difficulty in building heavy 
