I really never researched much on the DuVALL linebut noticed your postings and wanted to help out.
1907- David Chapman and Edna D DuVall married 14 Sep 1907 Hannibal,Marion,MO by Allen E. Dent, J.P. 1910- CHAPMAN DAVID JR 20 M W IL IL ADAMS 1-WD QUINCY-ADAMS COUNTY 1910 Series: T624Roll: 229Page: 44 1920- CHAPMAN DAVID B 30 M W IL IL ADAMS URSA-ADAMS COUNTY 1920 Series: T625Roll: 296Page: 10 1930- David B and Edna D DuVall Chapman moved to Davenport,Scott,IA. David died there in 1930 but his little family is listed on the 1930 IA Census.
I have the Adams County,IL cemetery,etc books if you need more just holler.
Gary Maize does obits, etc in Marion / Lewis,MO counties. E-Mail:email@example.com