ek_.

Here Captains Lewis and Clarke agreed to separate, for the purpose of
taking a more comprehensive survey of the country in their journey
homeward. It was considered desirable to acquire a further knowledge of
the Yellow-stone, a large river which flows from the south-west, more
than one thousand miles before it reaches the Missouri; and it was of
importance to ascertain, more accurately than they had hitherto done,
the course of Maria's river.

The separation took place on the 3d of July; and Captain Lewis, holding
on an eastern course, crossed a large stream which flowed towards the
Columbia, and which had already been named _Clarke's river_. On the 18th
of July he came to _Maria's river_, the object of his search; and he
continued for several days, his route along its northern bank. After
having ascertained the course of this river, he again set out on his
journey homeward, that he might not lose the opportunity of returning
before the winter.

He and his companions were only four in number; and, in one part of
their journey, they had an alarming intercourse with a party of Indians.
Not very long after this they embarked on the _Missouri_; and, with the
aid of their oars and the current, they proceeded at the rate of between
sixty and eighty miles a day. On the 7th of August they reached the
mouth of the _Yellow-stone river_, the place of rendezvous, appointed
with Captain Clarke. Here, by a note stuck upon a pole, they were
informed that he had accomplished his voyage along that river, and would
wait for them lower down the Missouri.

Captain Clarke, on quitting the central encampment at _Traveller's Rest
Creek_, had marched in a southerly direction, and had traversed a
distance of one hundred and sixty-four miles, to the head of
_Jefferson's river_. This journey was performed, on horseback, and in
six days, over a country by no means difficult; so that, in future, the
passage of this elevated region will be divested of a considerable
portion of its terrors. He also discovered that the communication
between the _Upper Missouri_ and the _Yellow-stone river_, was attended
with little trouble; for Gallatin's river, one of the tributary streams
of the Missouri, approaches within eighteen miles of the Yellow-stone,
and, at a place, where the latter is completely navigable.

Being unable to find wood of sufficient magnitude for the formation of
canoes, Captain Clarke and his men were obliged to proceed on horseb