,
or bighorn."

Two days later they were high up among the mountains, although the
ascent was not very steep. At that height they found the weather very
cool, so much so that on the morning of the sixth of July, after a cold
night, they had a heavy white frost on the ground. Setting out on that
day, Captain Clark crossed a ridge which proved to be the dividing line
between the Pacific and the Atlantic watershed. At the same time he
passed from what is now Missoula County, Montana, into the present
county of Beaver Head, in that State. "Beaver Head," the reader will
recollect, comes from a natural elevation in that region resembling the
head of a beaver. These points will serve to fix in one's mind the
route of the first exploring party that ever ventured into those wilds;
descending the ridge on its eastern slope, the explorers struck Glade
Creek, one of the sources of the stream then named Wisdom River, a
branch of the Jefferson; and the Jefferson is one of the tributaries of
the mighty Missouri. Next day the journal has this entry:--

"In the morning our horses were so much scattered that, although we sent
out hunters in every direction to range the country for six or eight
miles, nine of them could not be recovered. They were the most valuable
of all our horses, and so much attached to some of their companions that
it was difficult to separate them in the daytime. We therefore presumed
that they must have been stolen by some roving Indians; and accordingly
left a party of five men to continue the pursuit, while the rest went
on to the spot where the canoes had been deposited. We set out at ten
o'clock and pursued a course S. 56'0 E. across the valley, which we
found to be watered by four large creeks, with extensive low and
miry bottoms; and then reached (and crossed) Wisdom River, along the
northeast side of which we continued, till at the distance of sixteen
miles we came to its three branches. Near that place we stopped for
dinner at a hot spring situated in the open plain. The bed of the spring
is about fifteen yards in circumference, and composed of loose, hard,
gritty stones, through which the water boils in great quantities. It is
slightly impregnated with sulphur, and so hot that a piece of meat about
the size of three fingers was completely done in twenty-five minutes."

Next day, July 8, the party reached the forks of the Jefferson River,
where they had cached their goods in August, 1805; they had now
tr