I looked in my notebook. Actually, Daniel Green Calhoun and John Caldwell Calhoun (m. Louisa Caroline Scholars) were brothers.
Their parents were Dugald and Nancy McArthur Calhoun who came to Louisiana in 1858 and donated the land for the church in northern Louisiana that you can read about on Rootsweb.com and other places online. Their children were: Archibald Evander, John Caldwell (m. Scholars), Selina, Daniel Green (m. Dixon, Davis), Daniel Blue, Edward, Francis, Angus, Charles Holman, Mary Emmaline, Darius.
Too much to put here, but Daniel Green Calhoun named one of his sons John Caldwell who married Olga Josephine O'Neal. That's where I got mixed up before! And my great grandfather Dougal G. Calhoun was named for his grandfather Dugald above. My grandfather was Howard Dougal Calhoun.
Dugald Calhoun's parents were Archibald and Isobel Colquhoun. Archibald was one of the 6 or 7 siblings who came to Cape Fear, SC in 1790..I think. If you just google Calhoun or Colquhoun, you will find your ancestors. ALL Calhouns are kin. I posted on this site the 17th century portrait of Sir James Colquhoun of Luss. Not our direct line, but interesting. There is a lot of info out there and even the castle where they might have lived in Scotland.