"Mississippi" is most likely a misprint for "Missinippi", i.e.
Churchill river.
17.

Original had "McKenzie's"; changed to "Mackenzie's" to be consistent with other occurrences in the text.
18.

Original had "dependant"; changed to "dependent".
19.

Original had "agreeble"; corrected to "agreeable".
20.

Original had "oxycocoos"; corrected to "oxycoccos".
21.