Jayna, I found the marriage of David H. Barnett and Elizabeth Gould listed in two places, with two different dates: IGI at FamilySearch [LDS site] David H. Barnett to Elizabeth Gould 19 May 1881 Clay Co. IL and at Ancestry.com Family Trees: 19 May 1880 Clay County, IL
The Illinois Marriage Index at the State Archives site, does not show this marriage; I would go to the Clay County, Illinois GenWeb page and request free lookup to verify: http://www.rootsweb.com/~ilclay/http://www.rootsweb.com/~ilclay/
Volunteers will also check cemetery records, death records etc. so maybe you can find burial information for David and Elizabeth. You might want to contact Craig Beeman at firstname.lastname@example.org, who had the tree at Ancestry.com with David and Elizabeth's marriage. He does show that Elizabeth died 14 June 1890 in Clay County, IL, and he has information on her parents and backward; nothing further on David except the marriage date. He has your grandfather, Verla, shown as their son; born 30 August 1892 in Clay County and died about 1951, with burial in Camargo, Douglas County, IL.
1880 Bible Grove, Clay County, ILED 146/page 1511 June4/4 Gould, Loren42farmerb. ILfather: NYmother: VA Delia E. 38ILOHOH LIZZIE H. 17 daughterILILIL Zina P.14sonILILIL Ezra O.10sonILILIL Ella R.7daughter ILILIL Hettie C.1daughter ILILIL
Elizabeth Hannah Gould, daughter of Loren Gould, b. 11 May 1838 in Salem Pct. Edwards County, IL and Adelia Elizabeth Stanleyb. 24 January 1842, also in Salem Pct. Edwards County, IL[per Craig]
Hope this is helpful; I am not related, just a volunteer. Regards, Barbara