NAVIGABILITY OF THE MISSOURI. 247 
miles to the south of the Coteau, it appeared like a ‘‘ distant shore,” which sloped at an angle of 
about 30°, and whose height was about one hundred feet; but the ascent of it was so gradual, 
that when we were passing from the foot to the summit, we could not perceive that we were 
ascending. 
All the streams which have been mentioned are very small, and can never be of any value for 
navigation. They are liable, particularly the White Earth, to very high freshets. 
Connecting with the bluffs which limit the valley of the Missouri at Fort Union is a low ridge, 
which pursues a north-northwesterly course to about the parallel of 48° 38’, and thence runs to 
the northeast, and becomes merged into the Grand Coteau. 
This ridge divides the waters which flow into the Missouri above Fort Union from those which 
enter below. Where it turns to the northeast, there is a wide valley, through which flows a 
small stream connecting a series of ponds, marshes, and lake. This valley, from having been 
parallel to the ridge, turns to the west and continues in a direction towards the Big Muddy river, 
About thirty-two miles north-northwest of Fort Union is a chain of sand-hills, covered with 
a thick growth of small willow. These very much resemble what are called ‘‘moraines.” I 
noticed near the head of the Miry river an extensive outcrop of lignite, similar to that seen on 
the Missouri. 
I have to transmit herewith an itinerary of the country we passed over, a copy of the meteoro- 
logical observations, and a profile of the Missouri. 
The map which I wish to accompany this repo t is principally made up of Nicollet’s map 
below Fort Pierre, and of Lewis and Clark’s above that point, with some of our own observa- 
tions added to them. 
Of the collections made by the party on the Missouri and in the vicinity of Fort Union, those 
in the department of geology were directed to Dr. Evans, and sent to St. Louis, and those in the 
departments of natural history and botany to Professor Baird, and sent to Washington. 
I am, sir, very respectfully, your most obedient servant, 
; A. J. DONELSON, 
Second Lieutenant of Engincers. 
Gov. Isaac I. STEVENS, 
Chief of the Northern Pacific Railroad Survey. 
15. Report oF LIEUTENANT C. GROVER, U. S. A., OF HIS SURVEY OF THE UPPER MISSOURI, FROM 
THE GREAT FALLS TO CONNECT WITH THE SURVEY OF LIEUTENANT DONELSON. 
Str: I have the honor to submit the following as results of my survey of a portion of the 
Missouri river, made pursuant to your directions, in the latter part of September and the first part 
of October, 1853. 
The Missouri, from the Great Falls to near the mouth of the Muscle Shell, is a clear, rapid 
stream, of no great depth, and with a gravel bottom. Its general width, which for some miles 
below the falls is about two hundred yards, gradually increases as it flows on receiving its tribu- 
taries. As to its channel, it is quite variable, and its course is checked by many bars of gravel 
across its bed, causing rapids. At present I shall notice only those of the most importance as limit- 
ing the height to which boats can ascend, and the draught to which they must be confined to make 
the ascent. From the falls a succession of wild and impassable rapids extend some ten miles 
down, when they become less frequent, to the mouth of the High Wood creek, a small tributary 
which empties itself into the river on the right-hand side, and about fifieen miles below the falls. 
Immediately below the mouth of this tributary the river assumes the character which it retains 
as long as it flows over a gravelly bottom. The next rapid of importance is one that becomes so 
from the shallowness of the water, there being only fifteen inches on the bar. This rapid is 
