NAVIGABILITY OF THE MISSOURI. 239 
on the river, to the east and west at once, the destruction of the bank at any point succeeding, 
and being a consequence of that at a point above. And then, again, these supposed lines across 
the river are constantly shiftiag their position and direction, so that the difficulty of arriving at any 
general conclusions is manifest. I will mention one or two facts bearing on the subject: Lewis 
and Clark remarked that Blackbird’s hill was the first point above Council Bluff where the hills 
of the right bank touched the river. At present it is Wood’s hill. Nicollet mentions that the great 
bend opposite New Council Blufts had disappeared subsequently to his voyage, and that the river, 
which then flowed at the foot of the bluffs, had removed several miles to the east of them; now 
the bend has reappeared, and the river having returned to the bluffs, has again commenced 
moving to the east.” And, for aught I know, this change may have taken place more than once 
since Nicollet’s voyage. 
After passing several more rapids we reached Sergeant’s hill. The spot is noted as the burial 
place of Sergeant Floyd, who died there during Lewis and Clark’s exploration. Not far above 
is Floyd’s river, a stream with clear water, well-wooded banks, and whose width was about forty- 
five yards. 
After leaving the high bluffs on the left bank we passed the Big Sioux. It is about one hundred 
yards wide at its mouth, and navigable for steamboats to the rapids, and might be made so for 
a considerable distance by the expenditure of a small sum for its improvement. 
Above the Sioux the current was so rapid that we were several hours in going a few miles. 
The channel of the Missouri has, near here, changed within the last few years several miles 
from south to north. 
Coming to another rapid near a prairie on the right bank, resort was ‘made to the expedient, 
novel for a steamboat, of cordelling ; the crew cordelled the boat for about half a mile. 
On the 9th we were alongside of Hutan Kupey prairie, which extends up the river, on the left 
bank, from the Big Sioux to the Vermilion. On the right bank the bluffs were nearly all day 
close to the river. 
Near Dixon’s bluff commences the “‘cretaceous formation” described by Nicollet. 
With reference to the phenomenon of the hills, emitting smoke as if their interior was burning, 
which sometimes takes place in this vicinity, I will quote here the observations of Mr. Nicollet : 
“T believe * * that these pseudo volcanic phenomena may be compared with those described 
as occurring in other portions of the globe, under the name of terrains ardens ; although they are 
not here accompanied by the emission of flames. They are evidently due to the decomposition 
by the percolation of atmospheric waters to them, of beds of pyrites, which, reacting on the com- 
bustible materials, such as lignites, and other substances of a vegetable nature in their vicinity, 
give rise to spontaneous combustion; whilst further reactions (well understood by the chemist) 
upon the lime contained in the clay bed, produce the masses and crystals of selenite that 
are observed in the lower portions of this interesting deposit.” I was informed that a hill was 
seen emitting smoke in 1852 about eight miles above the Vermilion. 
The first lignite seen by us in ascending was on the left bank, not far above Vermilion river. 
From here it was occasionally met with as far as the mouth of the Poplar; but it was more 
fully developed between Fort Clark and Fort Berthold than elsewhere on the river. 
Hills which appear to have been subjected to the influence of fire, either combustion in their 
interior, or the burning of the vegetable substances on their surface, are occasionally to be 
observed on both banks, from near Dixon’s bluff to the mouth of the Poplar; but they are par- 
ticularly to be noticed on the right bank for some miles below the “Great Bend.” ‘Their soil 
has an ashy appearance, and they are almost destitute of vegetation. They are called by the 
traders ‘“ Les cotes brulées.”” The crystals of selenite to be found on their slopes, reflecting very 
strongly the rays of the sun immediately after rainy weather, have caused them to be called 
the “Shining Hills.’ These crystals were found by us, in greater abundance than elsewhere, 
on the hills on the right bank below the mouth of White river. In the vicinity of the same place 
