Thanks for your thoughtful reply. This would be "my" Archibald. He died in 1885 in Jamison, Mo. I did learn that his first wife was Margaret J Dunn, and Margaret's parents were Samuel Dunn and Sarah R Campbell. I found a Samuel Dunn in Jefferson County, Ky in 1820 and an Archibald Allen in Jefferson County Ky in 1810, but I don't know whether these are the parents of my great great grandparents or not, because I haven't been able to trace them any further, either forward or backward.
If you're a distant cousin, it's nice to "meet" you, and either way, thanks for your help!
Janice in Indiana