158 
GENERAL REMARKS. 
These examinations, therefore, become of great consequence: first, from the Bois des Sioux 
across the Missouri, through the Black Hills to the general region between the Yellowstone and 
Missouri, and thence to the best of the Hell Gate passes, (one is known to be practicable for a 
railroad;) and second, from the western frontier of Iowa and Missouri, through the Sioux hills, 
and uniting with the route from the Bois des Sioux and entering the pass together. 
The Black Hills are not as formidable as they are represented on the map ; on the contrary, quite 
an extensive region examined by Dr. Evans, the geologist of the expedition, south of the Mis¬ 
souri and Yellowstone, showed that the region was an elevated prairie ; and information has been 
received from reliable sources that the country is almost exclusively prairie in a straight line from 
the Hell Gate passes to Council Bluffs. 
Lieutenant Mullan writes me from the St. Mary’s valley that this is the opinion of his inter¬ 
preter, Gabriel, and that he has received similar information from a trapper who was familiar 
with the country. Major Ebbels, of San Francisco, a very intelligent gentleman, and who was in 
the employ of the Fur Company for many years, assures me that the hills are inconsiderable, 
and would not be an obstacle. 
From the results of Dr. Evans’ survey, I feel disposed to give much weight to the information 
thus derived from Lieutenant Mullan and Major Ebbels, and will therefore propose, in the event 
of the continuance of the survey, that these routes be explored. 
Should they prove practicable, the northern route to the head of navigation of the Mississippi, 
and to the Great Lakes, will be abridged about one hundred miles. The whole road, assuming St. 
Paul and the Fond du Lac of Lake Superior as the starting points, will be between the 45th and 
48th degrees of latitude. The distance from Seattle by the Snoqualme Pass, to Fond du Lac, to 
St. Paul and to Chicago, will be reduced from 1,905, 1,892, 2,215, to 1,805, 1,792, and 2,115 
miles, respectively. 
The route to Council Bluffs, to Chicago, and generally to the roads of Iowa and Missouri, will 
be reduced some 200 miles on that by the South Pass, and making the distances from Seattle to 
Council Bluffs and to Chicago 1,670, and 2,128 miles by the Hell Gate passes, and 1,992 and 
2,450 miles by the South Pass. 
So much for the importance of these two examinations coming within the scope of that clause 
of my instructions authorizing me to despatch the force not required west of the Rocky mountains 
homeward by new routes. At Fort Benton, if there had been animals to spare, I should have 
despatched a party to the Platte to examine one of the routes. My attention had been drawn 
to it before leaving Washington city. 
Besides which, there should be an exploration of the Snake river and its western tributaries, 
and of the Rocky mountains, from the South Pass to the 49th parallel, so far as may not be com¬ 
pleted by the labors of Lieutenant Mullan. The relations of the Salt Lake settlement with the 
region north of the Rocky mountains should be thoroughly established. 
The country should be explored from the Columbia lakes to the waters of San Francisco 
bay, to determine the best connexion between a road having its terminus in the Columbia valley 
and Puget sound, and roads having their terminus on the waters of San Francisco bay. It is a 
question whether this connexion can best be made west of the Cascades from the valley of the 
Willamette to that of thq Sacramento, or east of the Cascades. I will propose an exploration 
to determine the practicability of connecting, by a railroad, the two great valleys of the Willa¬ 
mette and the Sacramento. 
The relations of the Great Salt Lake region, both with the waters of San Francisco bay and 
the Columbia valley, should be ascertained. 
I will also recommend, most earnestly, an instrumental survey of the two routes, by the Co¬ 
lumbia valley and the Snoqualme Pass, to the sound, of the pass or passes in the Rocky mount¬ 
ains aiving the best connexion with the Great Lakes and the head of navigation of the Missis- 
sippi, and the roads now running through Iowa and Missouri, of different intermediate parts, and 
