Just thought I'd add that his age is 44 on the 1850, and his wife seems to be a widow on the 1860. In case you don't have it,

1860 Census
Lowndes County, MS
pg 51, family 348/362

E.R. Stephenson, 48, female, real estate $6000, personal estate $30000, born SC
R.A. Stephenson, 24, male, born MS
J.A. Stephenson, 16, male, MS
Elizabeth -, 12, MS
Daniel -, 10, MS
Samuel L. Betts, 26, AL

Is this him (died 1853)...

http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GSln=stephenson&GSbyrel=in&GSdyrel=in&GSst=27&GScnty=1555&GScntry=4&GSob=n&GRid=33858024&df=all&

and his wife...

http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GSln=stephenson&GSiman=1&GScid=63373&GRid=33858013&

Click on "Unity Cemetery" and enter the surname Stephenson for a list of others buried there.