EXTRACTS FROM TINKHAM’S REPORT. 87 
cost. The great valley of Milk river affords remarkable facilities for construction, as regards 
grading and the immediate use of the rail. Vicinity to the Missouri aids transportation of tim- 
ber from the mountains by rafting. 
An embankment road-bed must be resorted to in the valley of Milk river, to guard against rise 
of water upon the bottom land over which the line will pass. 
2. Extracts from Mr. Tinkham’s report.—From the Mississippi a vast prairie stretches westward 
to the base of the Rocky mountains, 1,136 miles; and a breadth of 402 miles of wooded and 
mountain country lies between the prairies and the great Columbia river plains. These prai- 
ries reach down to the bottom lands of the Columbia, whose valley, including that of its trib ‘tary, 
the Cowlitz, is traced to the shores of Puget sound—a third portion of 507 miles.  'Lhese 
are the measured distances of the railway route hereafter defined, and are changed by adopting 
for portions of the line other practicable or probably practicable routes. 
From the Mississippi to the bottom levels of the Missouri are certain prominent and unusual 
features, the knowledge of which is of great service in directing the location of the line of rail- 
way, the easiest and cheapest line between the headwaters of the Mississippi and the great 
northern bend which the Missouri makes near the mouth of the Yellowstone. It may nevertheless 
be observed, with reference to the region lying between the Mississippi and Missouri, that so far 
destitute is it of serious obstacles, that the great selection of a railway route uniting the two rivers 
may be determined by the commercial relation rather than by the physical features of the coun- 
try traversed. 
The section of Minnesota east of the Mississippi, passed over by the exploration, presents few 
difficulties to the building of a railroad. Obstructed by no mountain ranges, and diversified by 
lightly-wooded lands, the fertile belt of prairie bordering on the river affords a good location. 
Farther interior, on the east, and to the north and northwest, are the wooded and lumber sec- 
tions. 
Bordering on the Missouri, and running parallel with it, is the Plateau du Coteau du Missouri— 
a high rolling plateau, having an average breadth of some 60 to 80 miles, rising from 400 to 
800 feet above the bed of the river. This plateau, remarkable for its uniformity and extent 
from below the latitude 44°, stretches north and west into the British possessions, and probably 
here retains its characteristic features as the dividing ridge between the waters of the Sascat- 
chawan and the Missouri, until absorbed in the bolder elevations of the eastern slope of the 
Rocky mountains. 
The passage of the plateau by a railway will by no means be impracticable with a careful 
selection of route; but it can rarely be done without a loss of grade greater than 400 feet. 
East of the plateau and parallel with it, at distances of from 20 to 50 miles from its eastern 
edge. flows Riviére a Jacques, or James river, finding its source near the headwaters of the 
Shayenne, and having with that river, for some 100 miles, nearly the same general southeasterly 
course. 
The general surface of the high plains through which these two streams find their descent—the 
one fo the Red river of the North, the other to discharge its waters into the Missouri—is here 
400 to 600 feet lower than the plateau. Of this summit-ground, distributing and dividing the 
waters to their northern or southern slopes, the extensive flat or prairie through which flows the 
Bois des Sioux river is the eastern limit. The connexion between this prairie and the Mississippi 
is along the sources of the tributaries to the Minnesota river. Crossing these streams in their 
infancy, and before the crossing of the several valleys, is objectionable. 
Carrying the line northwardly to the great bend of the Missouri, we avoid a difficult and ob- 
jectionable river-crossing, and, what is of more importance, head what is represented as the 
extensive, broken, and tumultuous region of country south and west of the Missouri and ex- 
tending to the Platte, and known as the Black Hills. 
The railroad route from St. Paul keeps up the left bank of the Mississippi, crosses at Little 
