Sentence:  Bailly , after leaving Fort Snelling in August 1821 , was forced to leave some of the cattle at the Hudson's Bay Company's post on Lake Traverse `` in the Sieux Country '' and reached Fort Garry , as the Selkirk <WSD>Hudson's</WSD> Bay Company center was now called , late in the fall . 
Meaning of the word marked with <WSD> tags:  any number of entities (members) considered as a unit