Tuesday, 17th. Traveled about 16 miles; saw a large smoke rising out of the mountains before us. It had probably been raised by the Indians, as a telegraph, to warn the tribe that their land was visited by strangers. We were unable to procure any fuel this evening; we therefore slept without fire. The Indians found in this region are Shoshonees; they are friendly.
Indian smoke signals may be a tired trope of old Hollywood westerns, but smoke is a good way to send a simple message over a long distance and Indians did use this method of communication. Smoke signals were used not only by Native Americans of the Plains and Southwest, but also the Chinese, the Greeks, and other ancient cultures.
They are definitely in Shoshone country. The Shoshone tribe was spread across the Great Basin from southern Idaho to northern Utah and from Nevada to eastern Wyoming. At this time (1841) the Shoshone were friendly and peaceful, but increasing white encroachment would result in conflicts in the coming decades.