NAVIGABILITY OF THE MISSOURI. 247 



miles to the south of the Coteau, it appeared like a &quot; distant shore,&quot; 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 &quot;moraines.&quot; 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 report 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 Engineers. 



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. 



SIR : 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 fifteen 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 



