LETTER TO THE SECRETARY OF WAR. 
27 
Reserving to a subsequent portion of this report some account of Lieutenant Saxton’s admira¬ 
ble reconnaissance, one made under many difficulties, it will be sufficient for me to state that 
our mutual congratulations were of the most cordial character. He left Washington in April 
with instructions to organize a supply train on the Columbia, to establish a depot of animals 
and provisions at the St. Mary’s village, and, passing over the Blackfeet trail, to meet me at 
Fort Benton. 
It was in Washington determined to direct our first exploration on this pass. As we 
approached it from this side of the mountains, we called it Cadotte’s Pass, from Cadotte, one of 
our guides, who passed over it two years since. My first thought, on reaching Fort Benton, was 
to send forward Lieutenant Grover to ascertain whether he had reached St. Mary’s, or was on 
his way to this point. I point to the circumstance of their actual meeting within three miles 
of the dividing ridge, as some evidence of the goodness of the pass, and how well it was under¬ 
stood in the first instructions. 
Cadotte’s Pass is, by the barometer measurements of Lieutenant Saxton, nearly 3,000 feet 
below the South Pass, and is a much better route both in summer and in winter. It presents 
not the slightest difficulty to the jiassage of a railroad. 
A copy of my Order No. 18, published on Lieutenant Saxton’s arrival, shows the apprecia¬ 
tion which we have of his labors. 
I learned from Lieutenant Saxton that the passes in the Bitter Root and Cascade ranges were 
more difficult than those in the Rocky mountains; that they could not be crossed later than 
October, and that the greatest despatch must be used to reach the Pacific before the setting in 
of winter. I also learned that Captain McClellan was probably still struggling in the passes 
of the Cascade range, north of the Columbia, to ascertain the most practicable one, and that 
he could not be expected to push his line east of the Columbia the present season. 
My previous arrangements had been based on the winter not setting in till the middle or last 
of November, and on having before me at least a working season of eight weeks. I found it 
to be reduced, at the very outside, to six, and as regards the Bitter Root range, where snows 
fall on the 20th, and sometimes as early as the 10th of October, to five weeks. The plateau 
between the Milk and the Missouri rivers rises gently, and is, in almost every direction, prac¬ 
ticable for a railroad. 
The St. Mary’s valley connects with other valleys running both north and south at the base 
of the mountains, an aggregate distance of one hundred and fifty miles. Thus Cadotte’s Pass 
connects all the railroad lines north of the Missouri with all the lines from the Columbia to 
Puget sound. Accordingly I determined to leave my wagons at this point, to resort entirely 
to packs to send my whole force through Cadotte’s Pass with the greatest despatch, and direct 
them on several routes westward through the Bitter Root and Cascade ranges to ascertain the 
best pass, and to connect with Captain McClellan’s work, and thus endeavor to collect the 
present season the data to establish the practicability of a railroad from the headwaters of the 
Mississippi to Puget sound. 
The survey of the Marias Pass was deferred, and Mr. Lander, under orders for this service, 
was directed to report to Lieutenant Donelson, who was, by my orders of the 14th instant, a 
copy of which I herewith enclose, continued in charge of the main party operating in Cadotte’s 
Pass. It was with great reluctance I abandoned the survey of the Marias Pass. I am sanguine 
that it will prove the best pass, and it more naturally connects with the line of Clark’s fork of 
the Columbia river. The great obstacle to the survey of all these passes, and especially the 
Marias Pass, is in the immense forests which in all directions obstruct the way. The super¬ 
abundance of nature has to be done away with in a measure before the full measure of her gifts 
can be known. The Indians pursue the best trails they can find; but they have not axes to hew 
their way, nor, finding one pass practicable, have they the patience to search for better ones. 
To reach the valley of Clark’s fork, a road from Cadotte’s Pass must make a considerable 
deflection to the north, and it is believed that in no other direction can a road be run to the 
