Re: Wm Arnold, MS - TX
Checkout the Arnold family from Bedford Co., Tennessee. Members of that Arnold family settled in what is now Marshall, Union, Itawamba, and Tippah Co., MS at that same time period.
Darling Duke Arnold (son of Robert P. Arnold) was born 1796 NC and died 1863 Cooke Co., TX. He and his family moved from Bedford Co., TN into that part of Mississippi right after the 1840 Census was taken.
Darling Duke Arnold had five brothers according to the census records and I expect that some of their families left Tennessee with Darling Duke and settled in Mississippi. Seems like these families all migrated together.
Let me know what you find out!