I may have been wrong about "nobody" mentioning field hollers in the 19th century. There is at least one mention of something like them, in Northerner Frederick Law Olmsted's "A Journey in the Seaboard Slave States" (1856). Several blues historians quote it:

"At midnight I was awakened by loud laughter, and, looking out [of my railroad car], saw that the loading gang of negroes had made a fire, and were enjoying a right merry repast. Suddenly, one raised such a sound as I never heard before; a long, loud, musical shout, rising, and falling, and breaking into falsetto, his voice ringing through the woods in the clear, frosty night air, like a bugle-call. As he finished, the melody was caught up by another, and then, another, and then, by several in chorus."

Olmsted describes the practice as "Negro jodling." He mentions hearing it in South Carolina in 1853. If he heard it anywhere else, he says nothing about it.