I am trying to find information on a Lmb family from Arkansas (mainly from Sebastian county)

Nathan Lamb b.abt 1793 married Rebecca Simpson then eliza Simpson
Nathan was the farther of 11 children

John W Lamb (son of Nathan) b.abt 1835 married Martha J Patterson
John was the farther of 12 children, two died at young ages

William Nathan Lamb (son of John W) b.Jan 1861 married Mary Lula Stewart
William was the farther of 11 children, one died at young age

Uel Lawrence Lamb (son of William Nathan) B. Nov 1906 married Mabel Leona Nickelson
Uel was the farther of 2 children

I have the names and information on all other children and spouses. My search hits a brick wall before Nathan Lamb marries Rebecca Simpson. Any help????