I suppose it has always been known that there were Confederate soldiers buried at this cemetery so it was the natural assumption that a battle took place there. Since the cemetery is on the Middle Boggy in the Choctaw Nation, it seems natural to assume this was the battle Phillips said occurred on Middle Boggy in the Choctaw Nation.
Of the graves that have been identified at this cemetery, they were members of Dawson's 19th Ark who died during a measles outbreak. There are unidentified graves and there were graves destroyed, it is said, when the MK&T Railroad came through.
Do you know where her collection is located? Does OHS in OKC have it? I'm wondering if she did any specific research on the site -- being a Choctaw whose family lived at Boggy Depot, she may have collected much information on the area.