Thomas Rainey of Chester SC married first ? Humphries and had at least ten children (this number is based on my interpretation of census data below) and then married Sarah Ussery Brown ( - before 1844) in Chester County South Carolina. This is contrary to most Thomas Rainey data. But Sarah (Brown) Ussery is having children with John Brown from the 1790s into the 1800s in Virginia and the same time Thomas Rainey's children are being born in Chester SC. Further, the name Charles and Bennett which enters most of the Rainey children families is apparently from the Humphries family -- Charles Humphries and wife Mary Bennett.
http://www.bauer.uh.edu/parks/genealogy/rainey.htm