Complex sentence: He was one of the founders of the first Bank of Buffalo in 1831, and president of the Commercial bank in 1835 or 1836; in 1838 or 1840 he was president of the United States Bank at Buffalo.
Split into simpler sentences: He was one of the founders of the first Bank of Buffalo in 1831, and president of the Commercial bank in 1835 or 1836. And in 1838 or 1840 he was president of the United States Bank at Buffalo.