e conclude that the Missouri itself enters the Rocky mountains
to the north of 45 degrees. In writing to the president from our winter
quarters, we had already taken the liberty of advancing the southern
extremity of Mr. Fidler's discoveries about a degree to the northward,
and this from Indian information as to the bearing of the point at which
the Missouri enters the mountain; but we think actual observation will
place it one degree still further to the northward. This information of
Mr. Fidler however, incorrect as it is, affords an additional reason for
not pursuing Maria's river; for if he came as low even as 47 degrees and
saw only small streams coming down from the mountains, it is to be
presumed that these rivulets do not penetrate the Rocky mountains so far
as to approach any navigable branch of the Columbia, and they are most
probably the remote waters of some northern branch of the Missouri. In
short, being already in latitude 47 degrees 24' we cannot reasonably
hope by going farther to the northward to find between this place and
the Saskashawan any stream which can, as the Indians assure us the
Missouri does, possess a navigable current for some distance in the
Rocky mountains: the Indians had assured us also that the water of the
Missouri was nearly transparent at the falls; this is the case with the
southern branch; that the falls lay a little to the south of sunset
from them; this too is in favour of the southern fork, for it bears
considerably south of this place which is only a few minutes to the
northward of fort Mandan; that the falls are below the Rocky mountains
and near the northern termination of one range of those mountains: now
there is a ridge of mountains which appear behind the South mountains
and terminates to the southwest of us, at a sufficient distance from the
unbroken chain of the Rocky mountains to allow space for several falls,
indeed we fear for too many of them. If too the Indians had ever passed
any stream as large as this southern fork on their way up the Missouri,
they would have mentioned it; so that their silence seems to prove that
this branch must be the Missouri. The body of water also which it
discharges must have been acquired from a considerable distance in the
mountains, for it could not have been collected in the parched plains
between the Yellowstone and the Rocky mountains, since that country
could not supply nourishment for the dry channels which we passed on the
sout