David fought in the Colonial Army during the Revolutionary War. His powder horn, said to have been used by him in 1775 or 1776, was still in the family at Cassville, NY, in 1912. His brother Nathan joined the Loyalist forces.
David was the son of Nathan and Rebecca Lockwood Barnum. He married Anna Tower in New Fairfield, CT on 13 July 1756. They had at least two children, Nathan and David B. Anna died after 1758. David married Jemimah/Jemima Stevens on 22 March 1768. She was buried in the same cemetery. David and Jemima had at least six children: Samuel Towner, Sarajah Beardsley (buried in the same cemetery), Mehetebel and Ebenezer who were twins (Ebenezer was buried in the same cemetery), Jemima and Thaddeus (buried in the same cemetery). Jemima was the daughter of Ebenezer and Mehitable Peck Stevens.
The Beaver Bog Cemetery, which is located at the intersection of Bigelow Road, Beaver Bog Road and Route 37, was originally part of the Methodist Church. The present church was built in 1835 and was called the Methodist Episcopal Church. The building was built by Jesse and Isaac Scudder, Archibald Campbell, Hezekiah Wildman and Amos Stevens. Several of the early families buried at this cemetery belonged to the church. The cemetery separated from the church in 1935, since most of the original church members were then deceased. At this time it became the Beaver Bog Cemetery. An association was formed in later years to cover the maintenance. The oldest legible stone in the Beaver Bog Cemetery is that of Zebulon Plat, who died in 1809. This burial ground was recorded in 1915 and again in 1934. After comparing those records with the actual tombstones left in 1982, there were found to be 24 stones missing, destroyed or totally illegible. In 1908 a monument was erected there to honor the Revolutionary War soldiers buried at Beaver Bog Cemetery.