Wednesday, September 7.--Last night when all but the guards were asleep,
we were startled by a mountain lion's shrill scream, sounding so like
the human voice that for a moment I was deceived by it into believing
that some traveler in distress was hailing our camp. The stream near the
bank of which our camp lay, flows into the southeast arm of Yellowstone
lake, and for which the name "Upper Yellowstone" has been suggested by
some of our party; but Lieutenant Doane says that he thinks he has seen
on an old map the name "Bridger" given to some body of water near the
Yellowstone. We tried to cross the river near its mouth, but found the
mud in the bed of the stream and in the bottom lands adjoining too deep;
our horses miring down to their bellies. In accordance with plans agreed
upon last night, General Washburn and a few of the party started out
this morning in advance of the others to search for a practicable
crossing of the river and marshes, leaving the pack train in camp.

In company with Lieutenant Doane I went out upon a reconnaissance for
the purpose of determining the elevation of the mountains opposite our
camp, as well as the shape of the lake as far as we could see the
shore, and also to determine as far as possible our locality and the
best line of travel to follow in passing around the lake. There is just
enough excitement attending these scouting expeditions to make them a
real pleasure, overbalancing the labor attendant upon them. There is
very little probability that any large band of Indians will be met with
on this side of the lake, owing to the superstitions which originate in
the volcanic forces here found.

We followed along the high bank adjacent to the bottom through which the
river runs in a direction a little south of east for the distance of