An article by Phil and Vivian Williams, "Lewis and Clark Corps
of Discovery Quotes About Fiddling and Dancing"

https://www.voyagerrecords.com/arlc.htm

collects information about fiddling and dancing done during
the Lewis and Clark expedition. The Williamses write:

While fiddling and dancing appear many times in the
journals, none of the titles of the tunes played are
mentioned. The tunes would have been dance tunes extant in
1804 and familiar in the U.S.

We also know very little about the dancing that was done.
Other than the rather vague account of York’s dancing on
January 1, 1805, the only description we have of the dancing
comes from the oral history of the Nez Perce Indians. In
1936, Chief Many Wounds (Sam Lott), the great grandson of Red
Bear, a Nez Perce chief who helped Lewis and Clark, included
stories handed down in his family about Lewis and Clark in
his typewritten manuscript Historic Sketches of the Nez
Perces: Personal Incidents in the Lives of the Famous Chiefs
of the Nez Perce. He said “first time Nez Perces see fiddle
one man he play and sing and all others mans dance different
kind dance than Indians war dance and negro York he do lots
dance with feet and looks funny, all people laugh every body
was happy.” And “One white man named Potts ... he boss other
mans how to do funny dance and sing songs, and all laugh and
Lewis paint faces of Nez Perces with red paint.” This
indicates to us that York was step dancing, and that
Sergeant Potts was calling a cotillion (an early form of
square dance) or a longways set dance.

The account doesn't state explicitly whether Potts only "bossed"
the others before the music started or whether he actually
prompted the figures while the dance was in progress. I lean
toward the latter interpretation, but perhaps I'm being biased
by my experience of dance calling as currently practiced.

--Jim