She was born in 1798 in Craven, South Carolina. She married William B. Fussell in September of 1821 in Louisiana. She moved around a lot because in 1840, they were living in Rankin, Mississippi.
The first five children were born in Louisiana and the other eight were born in Mississippi. They lived in Mississippi until at least the 1850 census but in 1876, when she died at the age of 78, they were living in Woodville, Texas.
There is a write up in a book about the family that mentions that she was the wife of William B. Fussell. That's an encouraging tidbit because it verifies the marriage record.
Even more exciting, while I was writing this, I got my DNA results back from Ancestry.com. I find several 3rd and 4th cousins with a DNA match who are also related to Mary Morris and they have some sources I have not seen. Tells me I am on the right track.
With that, I am moving to Charlotte "Lottie" Warner, the next in line to the Mayflower.