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 Hudson's Bay Company center was now called , late in the <WSD>fall</WSD> . 
Meaning of the word marked with <WSD> tags:  the season when the leaves fall from the trees