Miss Fields, who came to be known as "Stagecoach Mary," stood tall and brawny by even frontier standards, weighing more than 200 pounds. Though she preferred men's clothes to women's, beneath her work apron she sometimes packed a .38 Smith & Wesson revolver. She was the only woman the local mayor permitted to drink in the saloons, where she favored hard liquor, smoked black cigars, and didn't shy from arguments, fistfights, or at least one confirmed duel.
As an EBONY magazine article later described that duel (authored in 1959 by actor Gary Cooper), "No one remembers how it turned out, but Mary was still around when it was over."
Whether out of fear or respect, Indians knew not to mess with Miss Fields' stagecoach. She was likely the first black person - man or woman - they had seen. There were many blacks in the Southwest but few in Montana.
According to The Adventures of the Negro Cowboys, Miss Fields was "perhaps the most remarkable" of the black women in western towns.
JC Reindl has published an interesting story about Stagecoach Mary, including a picture, in the Toledo Blade. You can read the article at http://toledoblade.com/apps/pbcs.dll/article?AID=/20100208/NEWS16/2080304.