From: Saving An Old Flag, Gus Norwood, http://www.fvhscc.org/1999history/flag.htm
The flag illustrates English heraldry which flourished in the 14th and 15th centuries. When Charles II granted the Hudson's Bay Company charter to his cousin Prince Rupert and 17 gentlemen in 1670, the sovereign visted the HBC area, he should receive as a tribute the furs of one fox, two elk and four beavers. These seven animals make up the heraldic design.
Under the shield with its red cross of St. George is the gold-lettered motto PRO BEEL CUTEM meaning "fair value in exchange for pelts." The HBC began using such a flag in 1767 both on its ships and its forts.
Dov Gutterman, 30 August 2000
In the book, Picturesque Canada the country as it was an and is (George M. Grant, Toronto: Belden, circa 1882), there is the following as he describes Warren's Landing (one of the HBC's posts) which is a supply point for Norway House:
Meantime, canoes and "York boats" are constantly arriving from the post, the steamer having been expected. One of the latter, bearing a great white flag with the arms and motto (PRO PELLE CUTEM) of the Hudson's Bay Company, brings the factor in charge of the district.