244 NAVIGABILITY OF THE MISSOURI. 
water of this stream had a deep muddy color, like that of the Missouri. It was about four hun- 
dred yards wide at its mouth, but this contained a large sand-bar. I was informed that the Yel- 
lowstone might be navigable for two hundred miles to rapids, these being susceptible of improve- 
ment, and beyond which no obstruction would occur for a considerable distance. If this were 
found by future examination to be correct, that river might become the means of communication, 
by steamboats, with a large area vf country; more particularly if it be supposed that favorable 
routes exist from the head of that navigation to Fort Laramie, Fort Hall, and the Salt lake, and 
to the valley of the Bitter Root river. 
A short distance below Fort Union the Missouri appeared, so to speak, entirely choked by 
sand-bars. For two or three hours the channel could not be found. But finally we proceeded 
by a narrow and deep slough, between a sand-bar and the left bank. We reached Fort Union 
at about seven p. m. 
The fourth was employed in unloading the boat of such freight as was not to go to Fort Benton. 
Her draught above Fort Union was about two feet. The Fur Company has a farm about eight 
miles below this post. Not much success has attended the attempts at cultivation. The grass- 
hoppers are a source of mich injury to the crops. On the morning of the fifth we proceeded, 
with the intention of going as far as the mouth of Milk river. I left all the party at Fort Union 
except Sergeant Collins and private Wilson, of the sappers. The river was averaged about two 
hundred yards wide, and was not unfavorable tor navigation. The channel was about seven feet 
deep, the river being nearly six feet below high-water mark. The current was not very rapid. 
The Missouri generally flowed through a narrow bottom, with bare, rugged, clay bluffs on each 
side. 
I would remark here that, during our ascent to Fort Clark, the river was generally rising at the 
rate of from two to seven inches during a night. 
At one point above Fort Union I noticed that the soil was rich, and somewhat resembled that 
in the State of Missouri. Some idea may be formed of the retentive nature of the soil above that 
post from the statement of the following fact: Directly afier a profuse rain, and when the rivulets 
were swollen, the rain-water was, for some distance, observed falling from the bank into the river 
in an unbroken sheet. ;, 
On the sixth we passed, in the afternoon, the mouth of the Poplar, a clear stream about sixty 
yards wide at its mouth. Just opposite was the dry bed of a stream about eighty yards wide, and 
now called “ Little Dry” creek. It was, I believe, named by Lewis and Clark “Two Thousand 
Miles” creek. Several extensive prairies are seen in this vicinity, particularly on the right bank, 
which produced nothing but wild sage. 
About seven miles above the mouth of the Poplar, there were encountered difficulties from 
sand-bars similar to those met with at Fort Union. I think they could have been overcome. But 
the managers of the boat thought best to return from this point. ‘They accordingly had carried 
ashore the Fort Benton freight, which was to be conveyed to that post by cordelling a large keel- 
boat. We returned to Fort Union on the ninth. No material obstructions were met with in our 
descent. The steamboat travelled with nearly three times the speed she did when ascending. 
We had an opportunity of verifying the survey of this portion of the river. It was found that 
the courses and features of the country were pretty accurately laid down, while the estimates of 
distances were somewhat erroneous. Wood appeared to be more abundant from Fort Berthold 
to the mouth of the Poplar than on any part of the river above the mouth of the Platte. I noted 
several different kinds of cotton-wood and willow. In travelling over so extensive a region from 
south to north, it was to be expected that changes would take place in the growth. I believe 
most of the trees which grow in southern latitudes disappear from the banks of the river south of 
the northern boundary of Missouri. The last sycamores to be seen in ascending were, I was 
informed, at the first bend above the “Mormon Winter Quarters.” In high water, the greater 
part of the banks of the Missouri may be thus described: They are from two to twenty feet high, 
