GEOGRAPHICAL MEMOIR. 235 
creek, which flows into it from the south 15 miles below the Great Falls. The Highwood has a 
large extent of fine arable land suitable for a military post, and is probably about the head of 
navigation. About five miles below the fort there is a rapid having but fifteen inches of water— 
this is the shallowest point—the next being twenty inches deep, and varying from this to 
twenty-six inches. Two or three points occur where there are large movable rocks, until the 
mouth of the Muscle Shell is passed. 
This is especially the case at Dauphin’s rapids, 16 miles below the mouth of Dog river, 
where, in addition, there is a current of 4} miles per hour. The current is stronger here than 
at any other point on the river. This refers to the river between the 20th and 30th September; 
earlier in the season, when the tributaries are supplied from the melting of the snow in the 
mountains, its depth is much greater; in the month of June it has three feet more water; from 
the first of August to the middle of ‘September it falls very gradually; and upon the first of 
September its depth is about one foot greater. This rise and fall of the river is very regular, 
and it is but little affected by the accidents of the 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 further 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. From the Muscle Shell downward towards the mouth of the Yellowstone the 
river changes. The water gradually becomes muddy from the washing away of the banks; the 
channel is constantly shifting its position; the forests of cottonwood with which the banks are 
lined, falling into the river, causes numerous snags and sawyers. Below the Yellowstone the 
Missouri assumes the same character it manifests to its mouth, it becomes thick and muddy 
with the alluvial deposit it is ceaselessly bearing on to the Gulf of Mexico. The bed of the 
river is much broader; the waters separate into many different channels, forming numerous 
sand islands, sometimes covered with forests of cottonwood. Referring to the navigation of 
ihe Missouri, it may be observed that, as regards the shallowest rapids, owing to the peculiar 
nature of the bottom, it being a mixture in many places of quicksand and fine gravel, it would 
give way very readily to the action of the paddle wheels, and admit of the passage of a boat 
drawing a greater amount of water than is actually found upon the bar. In order to take 
advantage of the rise of the water, the service should be so organized as to have two lines of 
steamers, one running from St. Louis to the mouth of the Yellowstone, and the other from that 
point to Fort Benton. The steamers which navigate the first portion of the river draw from 
three to four feet of water, and carry some five or six hundred tons of freight, and have ascended 
as high up as the mouth of Milk river. The navigability of the rapids could be so far improved, 
by removing the boulders and stones now obstructing the stream at the points referred to, that 
steamers drawing two feet of water and carrying from 200 to 250 tons could reach Fort Benton 
at the lowest stage of the river. This improvement would consist altogether in the removal of 
detached masses of rock, and could be easily done at low water and at small expense. The 
kind of steamers best adapted for the river are side-wheel steamers, with two separate, discon- 
nected engines, as such boats will more easily turn the sudden curves than any other kind. 
The river from St. Louis ta Fort Union has many snags in it, but during the 25 years the 
