Helen, there is some discussion of the Dungan family in posts 628-31 on this forum in relation to the TN family of Nathan Dungan.
In 1850 in the Madison Co TN census, Nathan's brother Allen has some of the children of Nathan living with him.I find Mary A. E.,age 20,Joseph H.(Hall) Dungan,age 16.Martha F.V.B., age 10,and Thomas M. age 18.
In the 1850 census of Dallas Co AL, Burnsville Beat, I find John B. (Bell) Dungan age 21 living with David Hamilton.
Other children of Nathan Dungan and Lilias Hamilton were listed in the Williamson County TN Archives at Franklin Library, and they were listed as follows: (Actually, that reference has some errors...my research shows:) John Bell Mary Martha Louise (m Milton Permenter) in 1880 census Joseph Hall m Sara Frances McLeod/McCloud (note: killed Jackson MS, Confederate Army) Sally (Sarah?) Udorah Parthenia Lulu Eleanor David Hamilton Dungan b 11 Mar 1839.
Second marriage of Nathan Dungan to Rebecca Berry Allen Gray Dungan 1852 Isaac Hill Dungan Willet Nathan 1858 (Wiley?) Fanny elizabeth 1860