What writer BESIDES Samual Clemens used the pen name Mark Twain (and this other person used it first)?

Who was born c. 1802 in Iredell County, N.C. and died Mar. 6, 1864, and was buried in St. Louis, MO.
He was a pioneer steamboat pilot who lived and died on the Mississippi.

http://showcase.netins.net/web/sellerfamily/isaiah.htm