8 ROUTE NEAR THE FORTY-SEVENTH AND FORTY-NINTH PARALLELS. 
parties were to determine the direction and intensity of the magnetic foree. They were to 
make a geological survey of the lines; to collect information upon, and specimens of, the botany 
and zoology of the country; and to obtain statistics of the Indian tribes which are found in the 
regions traversed. Thus would be obtained all the information for the general consideration of 
the question, as well as the data upon which the cost of construction and working a railroad 
depend. 
If the results of the explorations made under these instructions do not furnish the data requi- 
site to solve every question satisfactorily, they at least give a large amount of valuable in- 
formation, and place the question in a tolerably clear light. We see now, with some precision, 
the nature and extent of the difficulties to be encountered, and, at the same time, the means of 
surmounting them, 
As the readiest mode of communicating the nature and extent of the information contained 
in.the reports herewith submitted, a brief description of each route, its characteristic features, 
facilities, difficulties, and probable cost of construction, will be given. 
For a long distance west of the Mississippi, the enterprise of private companies, acting 
under State charters, has explored the country, and has projected or is constructing railroads, 
stretching towards the Pacific. As the examinations made under these auspices, and our 
general knowledge of that part of the country, afford the information necessary to determine 
all questions bearing upon the practicability of a railroad, it has been deemed unnecessary to 
incur the expense and delay of continuing the explorations directed by the act, eastward of 
the points reached, to which railroads are already projected, and consequently but one of the 
routes, the most northern, has its starting-point on the Mississippi. The connexion of the 
others with that river, as well as with the seaports of Atlantic and Gulf States, is shown by a 
table (B) hereto annexed, compiled from the best railroad maps. j 
ROUTE NEAR THE FORTY-SEVENTH AND FORTY-NINTH PARALLELS OF NORTH LATITUDE. 
Taking the routes in their geographical order, that near the 47th parallel, the general 
direction of the exploration of which was intrusted to Governor Stevens, of Washington 
Territory, will be the first discussed. 
The route was to cross the Rocky mountains at the sources of the tributaries of the Missouri 
and Columbia rivers, and, in approaching and leaving the mountains, to follow as far as prac- 
ticable the valleys of these rivers and their tributaries. 
The general direction of the Missouri from the Rocky mountains to the Great Bend, in lati- 
tude 48° 30’, is from west to east, and thence to latitude 43° 30’ southeast. The point where 
the direction changes is reached from St. Paul,.on the Mississippi, by a line passimg up on 
the east side of that river to Little Falls, 109 miles, and there crossing it; thence gaining the 
divide between the waters of Hudson’s bay and those of the Missouri, keeping on this divide, 
and approaching, in longitude 103°, within a few miles of the 49th parallel; then passing 
southerly, between the 104th and 105th meridians, and entering the valley of the Missouri river. 
The route then follows this valley to the mouth of Milk river. The ground near the Missouri 
here becoming rough and broken, the route is obliged to leave it and follow the valley of Milk 
river 187 miles; then entering the prairies, which near the mountains are more favorable 
for location than near the Missouri river, it continues in a line nearly parallel to the 
river, across its tributaries, the Marias, Teton, and Sun rivers, and enters either Clark’s 
or Cadotte’s Pass. 
As far as the crossing of Sun river, 1,093 miles from St. Paul, the route is over river bottom 
or prairie, the usual expense of construction over such ground being increased by the necessity 
of guarding against freshets by embankment on the river bottoms, of ballasting in the soft, 
sticky soil of Milk river, of providing supplies of water during the dry season, over certain 
portions of the route, by reservoirs and aqueducts, estimated to cost, with planting trees for 
supply of fuel, $3,000,000, and of transporting ties and lumber for distances of from 100 to 
