248 NAVIGABILITY OP THE MISSOURI. 



about five miles below Fort Benton. Immediately above the site of the old Fort McKey another 

 rapid occurs, twenty inches water on the bar; and one opposite Burnt island, about twelve miles 

 below Fort Benton, with twenty-two inches on the bar. There is no other obstacle upon either 

 of these bars than want of water. A rapid known as &quot;Publieus,&quot; a few miles below, had 

 twenty-three inches of water on the bar, but a clear channel. Another without a name, a few 

 miles below this again, had two feet on the bar, but this season had several large rocks near the 

 channel. But the worst point in the whole river, with the exception 1 perhaps of the one first men 

 tioned, is one which goes by the name of &quot;Dauphine s&quot; rapid, about sixteen miles below the 

 mouth of Dry river. Here a gravel bar extends across the whole river, and a small gravel island 

 near the middle divides the stream into two branches, of nearly the same depth, and causes 

 a bend in the channel of both ; in addition to this, boulders of a ton weight are frequently 

 found in and near the channel. The depth of water in the channel was twenty inches; 

 its rate did not exceed four and a half miles per hour. The current is stronger here than 

 at any other point on the river. There were several other rapids below this, but of no con 

 sequence as compared to it. From this point, which is about sixty miles above the mouth of 

 the Muscle Shell, the river-sand begins to alternate with the gravel of the bottom, and the rapids 

 and shallows become less frequent and the channel better; and, as we approach the mouth of 

 the Muscle Shell, the river begins to assume the characteristic appearance of the Missouri in every 

 respect; and below its mouth all obstacles to navigation for small boats may be considered at an 

 end. Its width gradually increases, and near the mouth of the Milk river its general width is 

 about four hundred yards. 



The above statements refer to the river between the 20th and 30th September. Earlier in the 

 season, when its tributaries are supplied from the melting of the snows in the mountains, its 

 depth is much greater. In the month of June it has about three feet more water; from the first 

 of August to the middle of September it falls very gradually, and upon the first of September the 

 depth is about one foot greater. This rise and fall of the river is very regular, and it is but little 

 affected by accidents of weather. During the high water the current is very rapid and severe, 

 and the small rapids are lost sight of. As to the large rocks sometimes found in the channel, 

 they are brought from high up the river by the ice as it goes out when the river breaks up. 

 During the winter they become attached to the under surface of the ice, and in its removal they 

 are taken along till they are rubbed off by some gravel bar or fall down by the melting of the ice; 

 the next season, if on a bar and near the surface, they again become frozen up with the ice and 

 are moved farther down. Thus they are constantly working their way down the river, and a bar 

 that this season is encumbered by them may be free the next. 



Conclusions with regard to Navigation. 



From the above statements it will be seen that the only obstructions to the navigation of the 

 river by steamboats are the shallowness of the water and the large boulders in the channel. But 

 the first does not exist as an obstruction to boats drawing twenty inches, before the middle of 

 September. As to the second obstruction, it can, I think, be obviated by providing a boat with 

 suitable grappling-hooks, with which she can hitch on to a rock in her way, and drop down with 

 it to deeper water, with but very little detention. A boat drawing twenty inches, loaded, can 

 then, I think, navigate the river from the opening of the season till the first of September with 

 perfect safety. Earlier in the season it is quite probable that boats of three feet draught would 

 find no difficulty in ascending, but, in order to be here in time, they would have to winter at Fort 

 Union. This fact, therefore, becomes of no practical advantage at present. As to wood for the 

 use of boats, plenty of it can be found upon the banks. 



A steamer of eighteen inches draught could, in my opinion, ascend the river at any time. 



C. GROVE R, 

 Second Lieutenant Fourth Artillery. 



Governor 1. 1. STEVENS. 



