Southern Bancorp of Arkadelphia, Ark. is buying Bank of Bolivar County, a small $15.9 million-asset Mississippi Delta bank. Bank of Bolivar County has two locations: one full-service office and one limited service branch. These will build on Southern Bancorp Bank's presence in Bolivar County, where it currently operates one branch. The acquisition marks a step forward for Southern Bancorp's efforts to increase the availability of capital to Mississippi residents; the bank is also in the process of adding its third branch in Hot Springs, Miss.