I hope this message gets to you, so many years after your initial posting.
I am very intrigued by your query.My husband is a descendant of Harrison H. Nixon, brother of the Samuel Nixon that both Mary Jane Higgins and her younger sister, Sarah E. Higgins were married to.
In your posting you mention that you have seen the grave of Newton Higgins.Where is it??Do you have a photo??
I know Dicy is buried at Bethel Methodist in Senoia, Coweta Co., Georgia.Mary Jane is buried on the old Nixon family grounds (abandoned) off Gordon Road, near the Meriwether Co. border in Coweta Co., as well as Samuel and thier parents and most likely Sarah.Only Samuel's grave is marked.
I would love to exchange info with you that you may be interested in regarding the Nixon line.
Valerie Freeman Tustin, California e-mail: firstname.lastname@example.org