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 <WSD>Sieux</WSD> Country '' and reached Fort Garry , as the Selkirk Hudson's Bay Company center was now called , late in the fall . 
Meaning of the word marked with <WSD> tags:  a point or extent in space