Thank you so much for your posting. I think you are onto something that has not been looked at before.
I too believed Sarah Jane Maxwell was married to someone else named Joel "Josiah" Williams, but after looking at your research I think that Sarah was a different person. In the 1880 census, that Sarah is listed as "Sarah A", obviously not the Sarah Jane Maxwell that was married to Thomas B. Coats.
I had previously believed that Thomas B. Coats died in the early 1860s, but your findings erase that mistake.
I found a reference to (2) marriage records for Thomas B. Coats and Mary S. Taylor. They were dated, 11/8/1878 and 3/22/1879, both records are found in Pope Co., IL marriage records.
Given that, I believe the following children belong to Sarah Jane and Thomas: Mary, Lucy, Sarah, Pauline, Charles, Amanda, and Ida.
In the 1880 census of Hamilton Co., TN, Thomas and Mary have a child born in August 1879, named James. I assume this is theirs since they were married prior to his birth.
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