A nice piece on Pemmican with Lewis & Clark and a band of Souix on the
afternoon of 26 Sep 1804, found at:
http://lewisandclarktrail.com/section2/sdcities/pierre/history1.htm  :

"after Captain Lewis had been on shore about 3 hours I became uneasy for
fear of Deception & sent a Serjeant to See him and know his treatment
which he reported was friendly & they were prepareing for a Dance this
evening. ."

Later in the afternoon, Lewis & Clark at Council  House: " under this
shelter about 70 men Set forming a Circle in front of the Chiefs  a plac
of 6 feet Diameter was clear and the pipe of the peace raised on sticks
under which there was Swans down scattered, on each Side of the Circle
two pipes, The flags of Spain 2 & the Flag we gave them in front of the
Grand Chief.  A large fire was near in which provisions were cooking in
the Center about 400 lbs. of excellent Buffalo Beef as a present for
us -  an old man rose and spoke approveing what we had done & informing
us of their situation and take pity on them .... The Great Chief then
rose with great state to the Same purpote as far as we Could learn &
then rose  with Great Solemnity  took up the pipe of the peace he took
one hand some of the most delicate parts of the Dog which was prepared
for the feist & made a sacrifice to the flag & after pointing it to the
heavens, the 4 quarters and the earth , lit it and prosist presented the
Stem to us to Smoke, after a Smoke had taken place, & a short Harange to
his people, we were requested to take the meal.  ( put before us the dog
which they had been cooking & Pemitigon* & ground potatoe in Several
platters.) All in good spirits this evening."   Clark

Pemitigon*  - Pemmican was meat dried and pulverized, mixed with melted
fat and stored in sealed leather satchels; various kinds of berries
might be added to improve the flavor.  Other kinds of meat than buffalo
might be used.  Best results were obtained in a sunny, dry climate like
that of the Great Plains.  Pemmican was a basic travel ration with
Indians and fur traders.  The Northwest and Hudson's Bay companies
carried on a considerable trade with the northern Plains tribes to
obtain pemmican for their employees in the sub-artic.  Pemmican come
from the Cree word pimikan," manufactured grease".