Saturday, 9th. Crossed Mary’s river where it led from the swamp into a lake beyond; our pilot led us south on the trail of Capt. B. Crossed a plain which is covered with water the greater part of the year — then came into sand hills, among which traveling was very laborious. Saw to the W. of us a lake, presenting a sheet of water 20 or 30 miles in extent. Encamped by another swamp, in which the water was very nauseous. Distance 28 miles.
They are traveling through an utter wasteland — no trees, no grass, no good water — just sand hills punctuated by swampy pools of nasty water. They try to follow in the tracks of Bartleson’s men, but the trail was easily lost in the arid soil. In his 1877 Dictation Bidwell says:
Thrown entirely upon our own resources to find our way as best we could through this region and into California, Benjamin Kelsey proved to be our best leader.
So we could call this the Kelsey-Bidwell Party. In the map below, the Humboldt River and Sink are at the upper right. From there the Kelsey-Bidwell Party were guided by the Indian guide southward to Carson Lake, and then westward to the Walker River. This was the river they would follow up into the Sierra Nevada.