Missouri River bottoms, Knife River area (North Dakota)
25th December Christmass Tuesday [1804]
"I was awakened before Day by a discharge of 3 platoons from the Party and the french, the men merrily Disposed, I give them all a little Taffia [rum or spirits] and permited 3 Cannon fired, at raising Our flag, Some men went out to hunt & the Others to Danceing and Continued untill 9 oClock P,M, when the frolick ended &c."
William Clark
Here "platoon" is used in its old sense of volleys, or a group of men firing in unison.
The above quote is taken directly from the Gary Moulton, University of Nebraska version of the Lewis and Clark Journals.